WorldWideScience
 
 
1

CREEP MODELING FOR INJECTION-MOLDED LONG-FIBER THERMOPLASTICS  

Energy Technology Data Exchange (ETDEWEB)

This paper proposes a model to predict the creep response of injection-molded long-fiber thermoplastics (LFTs). The model accounts for elastic fibers embedded in a thermoplastic resin that exhibits the nonlinear viscoelastic behavior described by the Schapery’s model. It also accounts for fiber length and orientation distributions in the composite formed by the injection-molding process. Fiber length and orientation distributions were measured and used in the analysis that applies the Eshelby’s equivalent inclusion method, the Mori-Tanaka assumption (termed as the Eshelby-Mori-Tanaka approach) and the fiber orientation averaging technique to compute the overall strain increment resulting from an overall constant applied stress during a given time increment. The creep model for LFTs has been implemented in the ABAQUS finite element code via user-subroutines and has been validated against the experimental creep data obtained for long-glass-fiber/polypropylene specimens. The effects of fiber orientation and length distributions on the composite creep response are determined and discussed.

Nguyen, Ba Nghiep; Kunc, Vlastimil; Bapanapalli, Satish K.

2008-06-30

2

From Process Modeling to Elastic Property Prediction for Long-Fiber Injection-Molded Thermoplastics  

International Nuclear Information System (INIS)

This paper presents an experimental-modeling approach to predict the elastic properties of long-fiber injection-molded thermoplastics (LFTs). The approach accounts for fiber length and orientation distributions in LFTs. LFT samples were injection-molded for the study, and fiber length and orientation distributions were measured at different locations for use in the computation of the composite properties. The current fiber orientation model was assessed to determine its capability to predict fiber orientation in LFTs. Predicted fiber orientations for the studied LFT samples were also used in the calculation of the elastic properties of these samples, and the predicted overall moduli were then compared with the experimental results. The elastic property prediction was based on the Eshelby-Mori-Tanaka method combined with the orientation averaging technique. The predictions reasonably agree with the experimental LFT data.

2007-01-01

3

From Process Modeling to Elastic Property Prediction for Long-Fiber Injection-Molded Thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

This paper presents an experimental-modeling approach to predict the elastic properties of long-fiber injection-molded thermoplastics (LFTs). The approach accounts for fiber length and orientation distributions in LFTs. LFT samples were injection-molded for the study, and fiber length and orientation distributions were measured at different locations for use in the computation of the composite properties. The current fiber orientation model was assessed to determine its capability to predict fiber orientation in LFTs. Predicted fiber orientations for the studied LFT samples were also used in the calculation of the elastic properties of these samples, and the predicted overall moduli were then compared with the experimental results. The elastic property prediction was based on the Eshelby-Mori-Tanaka method combined with the orientation averaging technique. The predictions reasonably agree with the experimental LFT data

Nguyen, Ba Nghiep; Kunc, Vlastimil; Frame, Barbara J.; Phelps, Jay; Tucker III, Charles L.; Bapanapalli, Satish K.; Holbery, James D.; Smith, Mark T.

2007-09-13

4

DAMAGE MODELING OF INJECTION-MOLDED SHORT- AND LONG-FIBER THERMOPLASTICS  

Energy Technology Data Exchange (ETDEWEB)

This article applies the recent anisotropic rotary diffusion – reduced strain closure (ARD-RSC) model for predicting fiber orientation and a new damage model for injection-molded long-fiber thermoplastics (LFTs) to analyze progressive damage leading to total failure of injection-molded long-glass-fiber/polypropylene (PP) specimens. The ARD-RSC model was implemented in a research version of the Autodesk Moldflow Plastics Insight (MPI) processing code, and it has been used to simulate injection-molding of a long-glass-fiber/PP plaque. The damage model combines micromechanical modeling with a continuum damage mechanics description to predict the nonlinear behavior due to plasticity coupled with damage in LFTs. This model has been implemented in the ABAQUS finite element code via user-subroutines and has been used in the damage analyses of tensile specimens removed from the injection-molded long-glass-fiber/PP plaques. Experimental characterization and mechanical testing were performed to provide input data to support and validate both process modeling and damage analyses. The predictions are in agreement with the experimental results.

Nguyen, Ba Nghiep; Kunc, Vlastimil; Bapanapalli, Satish K.; Phelps, Jay; Tucker III, Charles L.

2009-10-30

5

An Elastic-Plastic and Strength Prediction Model for Injection-Molded Long-Fiber Thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

This paper applies a recently developed model to predict the elastic-plastic stress/strain response and strength of injection-molded long-fiber thermoplastics (LFTs). The model combines a micro-macro constitutive modeling approach with experimental characterization and modeling of the composite microstructure to determine the composite stress/strain response and strength. Specifically, it accounts for elastic fibers embedded in a thermoplastic resin that exhibits the elastic-plastic behavior obeying the Ramberg-Osgood relation and J-2 deformation theory of plasticity. It also accounts for fiber length, orientation and volume fraction distributions in the composite formed by the injection-molding process. Injection-molded-long-glass-fiber/polypropylene (PP) specimens were prepared for mechanical characterization and testing. Fiber length, orientation, and volume fraction distributions were then measured at some selected locations for use in the computation. Fiber orientations in these specimens were also predicted using an anisotropic rotary diffusion model developed for LFTs. The stress-strain response of the as-formed composite was computed by an incremental procedure that uses the Eshelby’s equivalent inclusion method, the Mori-Tanaka assumption and a fiber orientation averaging technique. The model has been validated against the experimental stress-strain results obtained for these long-glass-fiber/PP specimens.

Nguyen, Ba Nghiep; Kunc, Vlastimil; Phelps, Jay; Tucker III, Charles L.; Bapanapalli, Satish K.

2008-09-01

6

Prediction of the Elastic-Plastic Stress/Strain Response for Injection-Molded Long-Fiber Thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

This paper proposes a model to predict the elastic-plastic response of injection-molded long-fiber thermoplastics (LFTs). The model accounts for elastic fibers embedded in a thermoplastic resin that exhibits the elastic-plastic behavior obeying the Ramberg-Osgood relation and J-2 deformation theory of plasticity. It also accounts for fiber length and orientation distributions in the composite formed by the injection-molding process. Fiber orientation was predicted using the anisotropic rotary diffusion model recently developed by Phelps and Tucker for LFTs. An incremental procedure using the Eshelby’s equivalent inclusion method and the Mori-Tanaka model is proposed to compute the overall stress increment resulting from an overall strain increment for an aligned fiber composite that contains the same fiber volume fraction and length distribution as the actual composite. The incremental response of the later is then obtained from the solution for the aligned fiber composite that is averaged over all possible fiber orientations using the orientation averaging method. Failure during incremental loading is predicted using the Van Hattum-Bernado model. The elastic-plastic and strength prediction model for LFTs was validated against the experimental stress-strain results obtained for long glass fiber/polypropylene specimens.

Nguyen, Ba Nghiep; Bapanapalli, Satish K.; Kunc, Vlastimil; Phelps, Jay; Tucker III, Charles L.

2009-01-26

7

Fiber Length and Orientation in Long-Fiber Injection-Molded Thermoplastics. Part I: Modeling of Microstructure and Elastic Properties  

Energy Technology Data Exchange (ETDEWEB)

This paper investigates the effects of fiber length and orientation distributions on the elastic properties of long-fiber injection-molded thermoplastics (LFTs). The corrected experimental fiber length distribution and the predicted and experimental orientation distributions were used in modeling to compute the elastic properties of the composite. First, from the fiber length distribution (FLD) data in terms of number of fibers versus fiber length, the probability density functions were built and used in the computation. Also, it has been shown that the two-parameter Weibull’s distribution can be used to represent the actual FLD. Next, the Mori-Tanaka model that employs the Eshelby’s equivalent inclusion method was applied to calculate the stiffness matrix of the aligned fiber composite containing the established FLD. The stiffness of the actual as-formed composite was then determined from the stiffness of the computed aligned fiber composite that was averaged over all possible orientations using the orientation averaging method. The methodology to predict the elastic properties of LFTs was validated via experimental verification of the longitudinal and transverse moduli determined for long glass fiber injection-molded polypropylene specimens. Finally, a sensitivity analysis was conducted to determine the effect of a variation of FLD on the composite elastic properties.

Nguyen, Ba Nghiep; Bapanapalli, Satish K.; Holbery, James D.; Smith, Mark T.; Kunc, Vlastimil; Frame, Barbara J.; Phelps, Jay; Tucker III, Charles L.

2008-05-01

8

Assessment of Current Process Modeling Approaches to Determine Their Limitations, Applicability and Developments Needed for Long-Fiber Thermoplastic Injection Molded Composites  

Energy Technology Data Exchange (ETDEWEB)

This report describes the status of the current process modeling approaches to predict the behavior and flow of fiber-filled thermoplastics under injection molding conditions. Previously, models have been developed to simulate the injection molding of short-fiber thermoplastics, and an as-formed composite part or component can then be predicted that contains a microstructure resulting from the constituents’ material properties and characteristics as well as the processing parameters. Our objective is to assess these models in order to determine their capabilities and limitations, and the developments needed for long-fiber injection-molded thermoplastics (LFTs). First, the concentration regimes are summarized to facilitate the understanding of different types of fiber-fiber interaction that can occur for a given fiber volume fraction. After the formulation of the fiber suspension flow problem and the simplification leading to the Hele-Shaw approach, the interaction mechanisms are discussed. Next, the establishment of the rheological constitutive equation is presented that reflects the coupled flow/orientation nature. The decoupled flow/orientation approach is also discussed which constitutes a good simplification for many applications involving flows in thin cavities. Finally, before outlining the necessary developments for LFTs, some applications of the current orientation model and the so-called modified Folgar-Tucker model are illustrated through the fiber orientation predictions for selected LFT samples.

Nguyen, Ba Nghiep; Holbery, Jim; Smith, Mark T.; Kunc, Vlastimil; Norris, Robert E.; Phelps, Jay; Tucker III, Charles L.

2006-11-30

9

Long fiber polymer composite property calculation in injection molding simulation  

Science.gov (United States)

Long fiber filled polymer composite materials have attracted a great attention and usage in recent years. However, the injection and compression molded long fiber composite materials possess complex microstructures that include spatial variations in fiber orientation and length. This paper presents the recent implemented anisotropic rotary diffusion - reduced strain closure (ARD-RSC) model for predicting fiber orientation distribution[1] and a newly developed fiber breakage model[2] for predicting fiber length distribution in injection and compression molding simulation, and Eshelby-Mori-Tanaka model[3,4] with fiber-matrix de-bonding model[5] have been implemented to calculate the long fiber composite property distribution with predicted fiber orientation and fiber length distributions. A validation study on fiber orientation, fiber breakage and mechanical property distributions are given with injection molding process simulation.

Jin, Xiaoshi; Wang, Jin; Han, Sejin

2013-05-01

10

An overview of long fiber reinforced thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

Long fiber reinforced thermoplastics (LFRTP) are a class of injection molding materials that extend the physical property envelope of thermoplastics polymers. These materials are manufactured by pulling continuous fiber tows through a thermoplastic polymer melt in a specialized processing die. The strands are subsequently cooled and chopped into pellets of equal length. LFRTP materials are available in virtually every common thermoplastic resin with glass, aramid, stainless steel, or carbon fiber reinforcement at levels up to 60% by weight. Unlike short fiber reinforced thermoplastics manufactured by conventional screw compounding processes, LFRTP exhibit simultaneous improvements in both flexural modulus and impact resistance. Improvements in load transfer, creep resistance at elevated temperatures, and dimensional stability can also be attributed to the long fiber network formed in the molded part. This unique combination of properties makes LFRTP the material of choice for replacement of metal structural assemblies in many automotive, industrial, consumer and recreational applications.

Bockstedt, R.J.; Skarlupka, R.J. [Polymer Composites Inc., Winona, MN (United States)

1995-12-01

11

Development of step for light duty truck by using injection molding of long-fiber reinforced thermoplastics; Chosen`i kyoka jushi no shashutsu keisei ni yoru truck yo step no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

The new step for light duty truck was developed by injection molding of glass long-fiber reinforced polypropylene. Feature of the step is good surface appearance and no post processings, compared with the conventional one press molded with a glass fiber reinforced polypropylene sheet (Stampable sheet). 3 refs., 14 figs., 6 tabs.

Togo, A.; Yamamura, H.; Yamaguchi, M. [Mitsubishi Motor Corp., Tokyo (Japan); Yoshino, K. [Kawasaki Steel Corp. Tokyo (Japan)

1997-10-01

12

Modeling Fatigue Damage in Long-Fiber Thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

This paper applies a fatigue damage model recently developed for injection-molded long-fiber thermoplastics (LFTs) to predict the modulus reduction and fatigue lifetime of glass/polyamide 6,6 (PA6,6) specimens. The fatigue model uses a multiscale mechanistic approach to describe fatigue damage accumulation in these materials subjected to cyclic loading. Micromechanical modeling using a modified Eshelby-Mori-Tanaka approach combined with averaging techniques for fiber length and orientation distributions is performed to establish the stiffness reduction relation for the composite as a function of the microcrack volume fraction. Next, continuum damage mechanics and a thermodynamic formulation are used to derive the constitutive relations and the damage evolution law. The fatigue damage model has been implemented in the ABAQUS finite element code and has been applied to analyze fatigue of the studied glass/PA6,6 specimens. The predictions agree well with the experimental results.

Nguyen, Ba Nghiep; Kunc, Vlastimil; Bapanapalli, Satish K.

2009-10-30

13

Modeling of the injection of loaded thermoplastic mixtures with application in metal injection molding  

Energy Technology Data Exchange (ETDEWEB)

The study is focussed on the modeling and numerical simulation of the loaded thermoplastic mixtures currently used in metal injection molding. Due to the fact that the mixture is highly concentrated in metallic powders, the models based on the homogenization theory and using an equivalent viscosity are no longer suitable. So a biphasic formulation has been developed to describe the flow of such mixtures. An interaction term between powder and thermoplastic fluid polymer accounts for segregation or debinding effects. In this type of the problem, the solid phase fraction is a key fields variable. The associated equations are solved separately for each phase taking into account interactions and coupling effects. A general solver in 2D and 3D has been developed that account propagation of fluid front by the extension to biphasic cases of the VOF method. For solving the velocity/pressure problem the fractional step method has been extended to the biphasic cases. Numerical simulations have been compared to the experimental results obtained by a using multiple cavity with pressure and temperature sensors. Comparisons between numerical simulation results and experiments show good agreements in terms of pressure and temperature evolutions during molding. It is also demonstrated that the numerical results are accurate and sensitive to variation of the injection molding marameters. (author)

Gelin, J.C.; Barriere, Th. [Univ. de Franche-Compte, Lab. de Mecanique Appliquee R. Chaleat, Besancon (France); Liu, B. [Southwest Jiaotong Univ., Inst. of Engineering Science, Chengdu, Sichuan (China)

2000-07-01

14

Modeling of the injection of loaded thermoplastic mixtures with application in metal injection molding  

International Nuclear Information System (INIS)

The study is focussed on the modeling and numerical simulation of the loaded thermoplastic mixtures currently used in metal injection molding. Due to the fact that the mixture is highly concentrated in metallic powders, the models based on the homogenization theory and using an equivalent viscosity are no longer suitable. So a biphasic formulation has been developed to describe the flow of such mixtures. An interaction term between powder and thermoplastic fluid polymer accounts for segregation or debinding effects. In this type of the problem, the solid phase fraction is a key fields variable. The associated equations are solved separately for each phase taking into account interactions and coupling effects. A general solver in 2D and 3D has been developed that account propagation of fluid front by the extension to biphasic cases of the VOF method. For solving the velocity/pressure problem the fractional step method has been extended to the biphasic cases. Numerical simulations have been compared to the experimental results obtained by a using multiple cavity with pressure and temperature sensors. Comparisons between numerical simulation results and experiments show good agreements in terms of pressure and temperature evolutions during molding. It is also demonstrated that the numerical results are accurate and sensitive to variation of the injection molding marameters. (author)

2000-01-01

15

Shear bond strength of an autopolymerizing repair resin to injection-molded thermoplastic denture base resins.  

Science.gov (United States)

Abstract Objective. This study investigated the shear bond strength of an autopolymerizing repair resin to injection-molded thermoplastic denture base resins. Materials and methods. Four injection-molded thermoplastic resins (two polyamides, a polyethylene terephthalate copolymer and a polycarbonate) were used in this study. The specimens were divided into eight groups according to the type of surface treatment given: (1) no treatment, (2) air abrasion with alumina, (3) dichloromethane, (4) ethyl acetate, (5) 4-META/MMA-TBB resin, (6) alumina and 4-META/MMA-TBB resin, (7) tribochemical silica coating or (8) tribochemical silica coating and 4-META/MMA-TBB resin. Half of the specimens in groups 1, 5, 6 and 8 were thermocycled for 10,000 cycles in water between 5-55°C with a dwell time of 1 min at each temperature. The shear bond strengths were determined. Results. The shear bond strengths to the two polyamides treated with alumina, dichloromethane and ethyl acetate and no treatment were very low. The greatest post-thermocycling bond strengths to polyamides were recorded for the specimens treated with tribochemical silica coating and 4-META/MMA-TBB resin (PA12: 16.4 MPa, PACM12: 17.5 MPa). The greatest post-thermocycling bond strengths to polyethylene terephthalate copolymer and polycarbonate were recorded for the treatment with alumina and 4-META/MMA-TBB resin (22.7 MPa, 20.8 MPa). Conclusion. Polyamide was exceedingly difficult to bond to an autopolymerizing repair resin; the shear bond strength improved using tribochemical silica coating followed by the application of 4-META/MMA-TBB resin. Both polyethylene terephthalate copolymer and polycarbonate were originally easy to bond to an autopolymerizing repair resin. However, with 4-META/MMA-TBB resin, the bond was more secure. PMID:23339746

Hamanaka, Ippei; Shimizu, Hiroshi; Takahashi, Yutaka

2013-01-23

16

Shear bond strength of an autopolymerizing repair resin to injection-molded thermoplastic denture base resins.  

UK PubMed Central (United Kingdom)

OBJECTIVE: This study investigated the shear bond strength of an autopolymerizing repair resin to injection-molded thermoplastic denture base resins. MATERIALS AND METHODS: Four injection-molded thermoplastic resins (two polyamides, a polyethylene terephthalate copolymer and a polycarbonate) were used in this study. The specimens were divided into eight groups according to the type of surface treatment given: (1) no treatment, (2) air abrasion with alumina, (3) dichloromethane, (4) ethyl acetate, (5) 4-META/MMA-TBB resin, (6) alumina and 4-META/MMA-TBB resin, (7) tribochemical silica coating or (8) tribochemical silica coating and 4-META/MMA-TBB resin. Half of the specimens in groups 1, 5, 6 and 8 were thermocycled for 10,000 cycles in water between 5-55°C with a dwell time of 1 min at each temperature. The shear bond strengths were determined. RESULTS: The shear bond strengths to the two polyamides treated with alumina, dichloromethane and ethyl acetate and no treatment were very low. The greatest post-thermocycling bond strengths to polyamides were recorded for the specimens treated with tribochemical silica coating and 4-META/MMA-TBB resin (PA12: 16.4 MPa, PACM12: 17.5 MPa). The greatest post-thermocycling bond strengths to polyethylene terephthalate copolymer and polycarbonate were recorded for the treatment with alumina and 4-META/MMA-TBB resin (22.7 MPa, 20.8 MPa). CONCLUSION: Polyamide was exceedingly difficult to bond to an autopolymerizing repair resin; the shear bond strength improved using tribochemical silica coating followed by the application of 4-META/MMA-TBB resin. Both polyethylene terephthalate copolymer and polycarbonate were originally easy to bond to an autopolymerizing repair resin. However, with 4-META/MMA-TBB resin, the bond was more secure.

Hamanaka I; Shimizu H; Takahashi Y

2013-09-01

17

An Elastic-Plastic Damage Model for Long-Fiber Thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

This article proposes an elastic-plastic damage model that combines micromechanical modeling with continuum damage mechanics to predict the stress-strain response of injection-molded long-fiber thermoplastics. The model accounts for distributions of orientation and length of elastic fibers embedded in a thermoplastic matrix whose behavior is elastic-plastic and damageable. The elastic-plastic damage behavior of the matrix is described by the modified Ramberg-Osgood relation and the three-dimensional damage model in deformation assuming isotropic hardening. Fiber/matrix debonding is accounted for using a parameter that governs the fiber/matrix interface compliance. A linear relationship between this parameter and the matrix damage variable is assumed. First, the elastic-plastic damage behavior of the reference aligned-fiber composite containing the same fiber volume fraction and length distribution as the actual composite is computed using an incremental Eshelby-Mori-Tanaka mean field approach. The incremental response of the latter is then obtained from the solution for the aligned-fiber composite by averaging over all fiber orientations. The model is validated against the experimental stress-strain results obtained for long-glass-fiber/polypropylene specimens.

Nguyen, Ba Nghiep; Kunc, Vlastimil

2009-08-11

18

Highly conductive thermoplastic composite blends suitable for injection molding of bipolar plates  

International Nuclear Information System (INIS)

This study aimed at developing highly conductive, lightweight, and low-cost bipolar plates for use in proton exchange membranes (PEM) fuel cells. Injection and compression molding of highly filled polypropylene, PP, and polyphenylene sulfide, PPS, based blends were used as a mean for mass production of bipolar plates. Loadings up to 60-wt% in the form of graphite, conductive carbon black and carbon fibers were investigated. The developed formulations have a combination of properties and processability suitable for bipolar plate manufacturing, such as good chemical resistance, sufficient fluidity, and good electrical and thermal conductivity. Electrical resistivities around 0.15 and 0.09 Ohm-cm were respectively achieved for the PP and PPS-based blends, respectively. Two bipolar plate designs were successfully fabricated by molding the gas flow channels over aluminum plates to form a metallic/polymer composite plate, or simply by direct injection molding of the conductive polymer composite. For the first design, overall plate resistivities of 0.2 and 0.1 Ohm-cm were respectively attained using PP and PPS based blends as conductive skin. A lower volume resistivity of around 0.06 Ohm-cm was attained for the second injected plate design with PPS based blend. (author)

2003-01-01

19

Characterization of thermoplastic polyurethane/polylactic acid (TPU/PLA) tissue engineering scaffolds fabricated by microcellular injection molding.  

UK PubMed Central (United Kingdom)

Polylactic acid (PLA) and thermoplastic polyurethane (TPU) are two kinds of biocompatible and biodegradable polymers that can be used in biomedical applications. PLA has rigid mechanical properties while TPU possesses flexible mechanical properties. Blended TPU/PLA tissue engineering scaffolds at different ratios for tunable properties were fabricated via twin screw extrusion and microcellular injection molding techniques for the first time. Multiple test methods were used to characterize these materials. Fourier transform infrared spectroscopy (FTIR) confirmed the existence of the two components in the blends; differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) confirmed the immiscibility between the TPU and PLA. Scanning electron microscopy (SEM) images verified that, at the composition ratios studied, PLA was dispersed as spheres or islands inside the TPU matrix and that this phase morphology further influenced the scaffold's microstructure and surface roughness. The blends exhibited a large range of mechanical properties that covered several human tissue requirements. 3T3 fibroblast cell culture showed that the scaffolds supported cell proliferation and migration properly. Most importantly, this study demonstrated the feasibility of mass producing biocompatible PLA/TPU scaffolds with tunable microstructures, surface roughnesses, and mechanical properties that have the potential to be used as artificial scaffolds in multiple tissue engineering applications.

Mi HY; Salick MR; Jing X; Jacques BR; Crone WC; Peng XF; Turng LS

2013-12-01

20

Characterization of thermoplastic polyurethane/polylactic acid (TPU/PLA) tissue engineering scaffolds fabricated by microcellular injection molding.  

Science.gov (United States)

Polylactic acid (PLA) and thermoplastic polyurethane (TPU) are two kinds of biocompatible and biodegradable polymers that can be used in biomedical applications. PLA has rigid mechanical properties while TPU possesses flexible mechanical properties. Blended TPU/PLA tissue engineering scaffolds at different ratios for tunable properties were fabricated via twin screw extrusion and microcellular injection molding techniques for the first time. Multiple test methods were used to characterize these materials. Fourier transform infrared spectroscopy (FTIR) confirmed the existence of the two components in the blends; differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) confirmed the immiscibility between the TPU and PLA. Scanning electron microscopy (SEM) images verified that, at the composition ratios studied, PLA was dispersed as spheres or islands inside the TPU matrix and that this phase morphology further influenced the scaffold's microstructure and surface roughness. The blends exhibited a large range of mechanical properties that covered several human tissue requirements. 3T3 fibroblast cell culture showed that the scaffolds supported cell proliferation and migration properly. Most importantly, this study demonstrated the feasibility of mass producing biocompatible PLA/TPU scaffolds with tunable microstructures, surface roughnesses, and mechanical properties that have the potential to be used as artificial scaffolds in multiple tissue engineering applications. PMID:24094186

Mi, Hao-Yang; Salick, Max R; Jing, Xin; Jacques, Brianna R; Crone, Wendy C; Peng, Xiang-Fang; Turng, Lih-Sheng

2013-08-02

 
 
 
 
21

Characteristics of thermoplastics containing electrically conducting asymmetric particles - anisotropic electrical conductivity of injection molded parts and extrusion behavior  

Energy Technology Data Exchange (ETDEWEB)

The characteristics of compounds of acrylonitrile-butadiene-styrene and high impact polystyrene resins filled with carbon fibers, steel fibers, carbon black, and aluminum flakes have been investigated with special emphasis on electrical conductivity and flow behavior in a capillary rheometer. Compression- and injection-molded compounds were found to be highly electrically anisotropic. The components of the electrical conductivity tensor, were measured. Generally, kappa-11, the flow direction conductivity, has the highest value and the thickness direction, and kappa-33 has the lowest. The injection-molded parts were usually electrically heterogeneous, with the conductivities highest at the greatest distances from the gate. The flow of these compounds through dies was investigated. Examination of material from the die entrance indicated streamline flow without entrance vortices. Extrudates were found to contain oriented particles. 25 references.

Martinsson, J.; White, J.L.

1986-10-01

22

Relationship between fiber degradation and residence time distribution in the processing of long fiber reinforced thermoplastics  

Directory of Open Access Journals (Sweden)

Full Text Available Long fiber reinforced thermoplastics (LFT) were processed by in-line compounding equipment with a modified single screw extruder. A pulse stimulus response technique using PET spheres as the tracer was adopted to obtain residence time distribution (RTD) of extrusion compounding. RTD curves were fitted by the model based on the supposition that extrusion compounding was the combination of plug flow and mixed flow. Characteristic parameters of RTD model including P the fraction of plug flow reactor (PFR) and d the fraction of dead volume of continuous stirred tank reactor (CSTR) were used to associate with fiber degradation presented by fiber length and dispersion. The effects of screw speed, mixing length and channel depth on RTD curves, and characteristic parameters of RTD models as well as their effects on the fiber degradation were investigated. The influence of shear force with different screw speeds and variable channel depth on fiber degradation was studied and the main impetus of fiber degradation was also presented. The optimal process for obtaining the balance of fiber length and dispersion was presented.

2008-01-01

23

Computer-aided injection molding system  

Science.gov (United States)

Achievements are reported in cavity-filling simulation, modeling viscoelastic effects, measuring and predicting frozen-in birefringence in molded parts, measuring residual stresses and associated mechanical properties of molded parts, and developing an interactive mold-assembly design program and an automatic NC maching data generation and verification program. The Cornell Injection Molding Program (CIMP) consortium is discussed as are computer user manuals that have been published by the consortium. Major tasks which should be addressed in future efforts are listed, including: (1) predict and experimentally determine the post-fillin behavior of thermoplastics; (2) simulate and experimentally investigate the injection molding of thermosets and filled materials; and (3) further investigate residual stresses, orientation and mechanical properties.

Wang, K. K.; Shen, S. F.; Cohen, C.; Hieber, C. A.; Isayev, A. I.

1982-10-01

24

Low-pressure injection molding  

Energy Technology Data Exchange (ETDEWEB)

Ceramic injection molding experienced a revival in the 1970s and 1980s with the application of ceramics for gas turbine components. Concurrently, techniques were being developed for the injection molding of powdered metal compositions into complex shaped articles. The impetus for the development of injection molding as a ceramic fabrication process lay in the potential to produce complex-shaped components to near-net shape. In the ceramic injection molding process, ceramic powders are processed to obtain the desired particle size, distribution and morphology and blended to obtain a homogeneous distribution. These powders are then mixed with the organic binders, generally in a heated, highshear mixer at temperatures above the melting point of the organic binders. The injection molding mix is pelletized, cooled and fed into an injection molding machine. The molding mix is reheated to a fluid state and injected under high pressure (7--70 MPa) into a die cavity. The molded part is removed from the tooling after the molding mix has solidified in the die. The organic binders are then removed from the component at temperatures up to 400 C, generally by some combination of wicking and thermal decomposition. Finally, the component is sintered to obtain its final ceramic properties, using conventional ceramic processes.

Mangels, J.A. (Ceradyne Inc., Costa Mesa, CA (United States))

1994-05-01

25

Injection-molded PZT actuators  

Science.gov (United States)

Ceramics injection molding technology is being adapted for the fabrication of net shape piezoelectric actuators of lead zirconate titanate (PZT) and lead magnesium niobate (PMN). INjection molding offers low cost, high quality actuator components with a high degree of part-of-part reproducibility. Configurations under investigation include a proprietary high displacement linear element, air acoustic actuators, tube array actuators, benders, and various multilayer designs. Applications include conformable unidirectional patches for active noise and vibration control, high displacement bender actuators for active vortex generators and synthetic jets, high force-high displacement actuators for rotorblade flaps, and air acoustic actuators for active noise reduction.

Near, Craig D.; Schmidt, Gerald; McNeal, Kelley; Gentilman, Richard L.

1998-06-01

26

The use of variable speed drives to retrofit hydraulic injection molding machines  

Energy Technology Data Exchange (ETDEWEB)

Injection molding is a common method of plastic processing in which thermoplastic materials can be molded into arbitrary complex shapes. Most injection molding machines use complicated hydraulic systems to perform the necessary work of the process. Hydraulic system flow and pressure requirements vary throughout the cycle and in many cases, excess fluid that is not required by the process is throttled back to the reservoir, wasting motor energy and producing additional thermal load on the cooling system. Variable speed drives can be used to allow injection molding machine hydraulic systems to vary the amount of fluid being pumped and thus reduce the amount of fluid that is throttled reducing the amount of wasted energy. This article discusses injection molding machine processes and develops a protocol for assessing the efficacy of variable speed drive retrofits for hydraulic injection molding machines.

Ambs, L.; Frerker, M.M. [Univ. of Massachusetts, Amherst, MA (United States)

1998-06-01

27

Gastroresistant capsular device prepared by injection molding.  

Science.gov (United States)

In the present work, the possibility of manufacturing by injection molding (IM) a gastro-resistant capsular device based on hydroxypropyl methyl cellulose acetate succinate (HPMCAS) was investigated. By performing as an enteric soluble container, such a device may provide a basis for the development of advantageous alternatives to coated dosage forms. Preliminarily, the processability of the selected thermoplastic polymer was evaluated, and the need for a plasticizer (polyethylene glycol 1500) in order to counterbalance the glassy nature of the molded items was assessed. However, some critical issues related to the physical/mechanical stability (shrinkage and warpage) and opening time of the device after the pH change were highlighted. Accordingly, an in-depth formulation study was carried out taking into account differing release modifiers potentially useful for enhancing the dissolution/disintegration rate of the capsular device at intestinal pH values. Capsule prototypes with thickness of 600 and 900 ?m containing Kollicoat(®) IR and/or Explotab(®) CLV could be manufactured, and a promising performance was achieved with appropriate gastric resistance in pH 1.2 medium and break-up in pH 6.8 within 1h. These results would support the design of a dedicated mold for the development of a scalable manufacturing process. PMID:22683648

Zema, Lucia; Loreti, Giulia; Melocchi, Alice; Maroni, Alessandra; Palugan, Luca; Gazzaniga, Andrea

2012-06-05

28

Gastroresistant capsular device prepared by injection molding.  

UK PubMed Central (United Kingdom)

In the present work, the possibility of manufacturing by injection molding (IM) a gastro-resistant capsular device based on hydroxypropyl methyl cellulose acetate succinate (HPMCAS) was investigated. By performing as an enteric soluble container, such a device may provide a basis for the development of advantageous alternatives to coated dosage forms. Preliminarily, the processability of the selected thermoplastic polymer was evaluated, and the need for a plasticizer (polyethylene glycol 1500) in order to counterbalance the glassy nature of the molded items was assessed. However, some critical issues related to the physical/mechanical stability (shrinkage and warpage) and opening time of the device after the pH change were highlighted. Accordingly, an in-depth formulation study was carried out taking into account differing release modifiers potentially useful for enhancing the dissolution/disintegration rate of the capsular device at intestinal pH values. Capsule prototypes with thickness of 600 and 900 ?m containing Kollicoat(®) IR and/or Explotab(®) CLV could be manufactured, and a promising performance was achieved with appropriate gastric resistance in pH 1.2 medium and break-up in pH 6.8 within 1h. These results would support the design of a dedicated mold for the development of a scalable manufacturing process.

Zema L; Loreti G; Melocchi A; Maroni A; Palugan L; Gazzaniga A

2013-01-01

29

Injection Molding of Plastics from Agricultural Materials  

Energy Technology Data Exchange (ETDEWEB)

The objective of this research was to conduct a systematic study to relate injection molding parameters to properties of blends of starch and synthetic polymer. From this study, we wished to develop a thorough understanding of the injection molding process and gain significant insight into designing molds and aiding in developing products cheaply and efficiently.

Bhattacharya, M.; Ruan, R.

2001-02-22

30

Injection Molding of High Aspect Ratio Nanostructures  

DEFF Research Database (Denmark)

We present a process for injection molding of 40 nm wide and >100 nm high pillars (pitch: 200 nm). We explored the effects of mold coatings and injection molding conditions on the replication quality of nanostructures in cyclic olefin copolymer. We found that optimization of molding parameters using native nickel molds only lead to slight improvements in replication quality. In contrast, a fluorocarbon based antistiction coating (FDTS) was found to improve the replication quality significantly.

Matschuk, Maria; Larsen, Niels Bent

31

Feed stock preparation and achievement of shape complexity using powder injection molding (PIM)  

International Nuclear Information System (INIS)

Powder injection molding is one of the near net shape processing (NNSP) techniques used to produce geometrically complex shapes that need very little or no machining. This study presents the comparative study of feedstock preparation for Metal and Ceramic Injection Molding from the view point of achievement of shape complexity. Different variables of feedstock are studied, such as the role of binder, processing temperature, role of additives and the starting powder attributes on shape complexity. In this study, different binder systems; paraffin wax, polyethylene glycol, stearic acid, several thermoplastic resins and powders Fe and Al/sub 2/O/sub 3/ are studied. The differences between metal injection molding and ceramic injection molding are clearly emphasized. A major focus of this study is to attain the requisite engineering properties by a control of microstructure using different dies with increasing shape complexity. Powder is mixed with the binder system, the mix is injection molded into the desired shape cavity, the molded part is de-bound and after debinding it is sintered to produce high density products. (author)

2007-01-01

32

Injection molded polymer chip for electrochemical and electrophysiological recordings from single cells  

DEFF Research Database (Denmark)

We present a novel method to fabricate an all in polymer injection molded chip for electrochemical cell recordings and lateral cell trapping. The complete device is molded in thermoplastic polymer and it results from assembling two halves. We tested spin-coated conductive polymer poly(3,4-ethylenedioxythiopene) and showed that it can be used as an electrode material for detecting neurotransmitters electrochemically in biosensors.

Tanzi, Simone; Larsen, Simon Tylsgaard

33

Progress in Titanium Metal Powder Injection Molding  

Directory of Open Access Journals (Sweden)

Full Text Available Metal powder injection molding is a shaping technology that has achieved solid scientific underpinnings. It is from this science base that recent progress has occurred in titanium powder injection molding. Much of the progress awaited development of the required particles with specific characteristics of particle size, particle shape, and purity. The production of titanium components by injection molding is stabilized by a good understanding of how each process variable impacts density and impurity level. As summarized here, recent research has isolated the four critical success factors in titanium metal powder injection molding (Ti-MIM) that must be simultaneously satisfied—density, purity, alloying, and microstructure. The critical role of density and impurities, and the inability to remove impurities with sintering, compels attention to starting Ti-MIM with high quality alloy powders. This article addresses the four critical success factors to rationalize Ti-MIM processing conditions to the requirements for demanding applications in aerospace and medical fields. Based on extensive research, a baseline process is identified and reported here with attention to linking mechanical properties to the four critical success factors.

Randall M. German

2013-01-01

34

Surface microstructure replication in injection molding  

DEFF Research Database (Denmark)

In recent years, polymer components with surface microstructures have been in rising demand for applications such as lab-on-a-chip and optical components. Injection molding has proven to be a feasible and efficient way to manufacture such components. In injection molding, the mold surface topography is transcribed onto the plastic part through complex mechanisms. This replication, however, is not perfect, and the replication quality depends on the plastic material properties, the topography itself, and the process conditions. This paper describes and discusses an investigation of injection molding of surface microstructures. The fundamental problem of surface microstructure replication has been studied. The research is based on specific microstructures as found in lab-on-a-chip products and on rough surfaces generated from EDM (electro discharge machining) mold cavities. Emphasis is put on the ability to replicate surface microstructures under normal injection-molding conditions, i.e., with commodity materials within typical process windows. It was found that within typical process windows the replication quality depends significantly on several process parameters, and especially the mold temperature. For the specific microstructures, evidence suggests that step-height replication quality depends linearly on structure width in a certain range

Theilade, Uffe ArlØ; Hansen, Hans NØrgaard

2006-01-01

35

All-in-polymer injection molded device for single cell capture using multilevel silicon master fabrication  

DEFF Research Database (Denmark)

This work demonstrates a novel all-in-polymer device for single cell capture applicable for biological recordings. The chip is injection molded and comprises a "cornered" (non planar) aperture. It has been demonstrated how cornered apertures are straightforward to mold in PDMS [1,2]. In this study we demonstrate cornered apertures made in a thermoplastic polymer. One of the advantages of cornered apertures is the ease of microscopy under a standard inverted optical microscope, when using transparent materials. After the part is injection molded, the sealing of the chip is performed by thermal bonding to a polymer foil, so the complete device results from only two parts. It differs from similar devices in the novel material and fabrication platform that enables high reproducibility and inexpensive mass production. Optimization of the fabrication scheme has been carried out in order to avoid defects during demolding. Capturing of single PC12 cells has been demonstrated.

Tanzi, S.; Larsen, S.T.

2012-01-01

36

Effect of cross sectional geometry on PDMS micro peristaltic pump performance: comparison of SU-8 replica molding vs. micro injection molding.  

Science.gov (United States)

Two different fabrication methods were employed to fabricate micropumps with different cross-sectional channel geometries. The first was to fabricate rectangular cross-sectional microchannel geometries using the well known fabrication method of replica molding (REM). The second, and far less utilized fabrication technique, was to create microchannel molds using an in-house fabricated handheld micro injection molding apparatus. The injection mold apparatus was designed for use with elastomeric room temperature vulcanization (RTV) polymers, as opposed to most other injection molding machines, which are designed for use with thermoplastic polymers. The injection mold's bottom plate was used as a microchannel molding template. The molding template was created by threading a small-diameter wire (150 ?m or less) through the injection mold's bottom plate, with subsequent adhesion and smoothing of a thin piece of aluminum foil over the wire-raised injection mold template. When molded against, the template produced a rounded/Gaussian-shaped PDMS microchannel. The design of the injection mold will be presented, along with a direct comparison for micropump performance metrics such as flow rate, valving characteristics, and maximum backpressures attainable for each of the respective micropump channel geometries. PMID:23917263

Graf, Neil J; Bowser, Michael T

2013-08-27

37

Effect of cross sectional geometry on PDMS micro peristaltic pump performance: comparison of SU-8 replica molding vs. micro injection molding.  

UK PubMed Central (United Kingdom)

Two different fabrication methods were employed to fabricate micropumps with different cross-sectional channel geometries. The first was to fabricate rectangular cross-sectional microchannel geometries using the well known fabrication method of replica molding (REM). The second, and far less utilized fabrication technique, was to create microchannel molds using an in-house fabricated handheld micro injection molding apparatus. The injection mold apparatus was designed for use with elastomeric room temperature vulcanization (RTV) polymers, as opposed to most other injection molding machines, which are designed for use with thermoplastic polymers. The injection mold's bottom plate was used as a microchannel molding template. The molding template was created by threading a small-diameter wire (150 ?m or less) through the injection mold's bottom plate, with subsequent adhesion and smoothing of a thin piece of aluminum foil over the wire-raised injection mold template. When molded against, the template produced a rounded/Gaussian-shaped PDMS microchannel. The design of the injection mold will be presented, along with a direct comparison for micropump performance metrics such as flow rate, valving characteristics, and maximum backpressures attainable for each of the respective micropump channel geometries.

Graf NJ; Bowser MT

2013-08-01

38

Binder Removal from Powder Injection Molded 316L Stainless Steel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study reports the results of preparation of 316L stainless steel polymer based injection molded feed stock, rheology of feed stock and injection molding. The plastic binder was extracted from molded samples. The binder extraction was carried out in two steps: by solvent and thermal techniques. ...

Muhammad Rafi Raza; Faiz Ahmad; M.A. Omar; R.M. German

39

Dynamic Feed Control For Injection Molding  

Energy Technology Data Exchange (ETDEWEB)

The invention provides methods and apparatus in which mold material flows through a gate into a mold cavity that defines the shape of a desired part. An adjustable valve is provided that is operable to change dynamically the effective size of the gate to control the flow of mold material through the gate. The valve is adjustable while the mold material is flowing through the gate into the mold cavity. A sensor is provided for sensing a process condition while the part is being molded. During molding, the valve is adjusted based at least in part on information from the sensor. In the preferred embodiment, the adjustable valve is controlled by a digital computer, which includes circuitry for acquiring data from the sensor, processing circuitry for computing a desired position of the valve based on the data from the sensor and a control data file containing target process conditions, and control circuitry for generating signals to control a valve driver to adjust the position of the valve. More complex embodiments include a plurality of gates, sensors, and controllable valves. Each valve is individually controllable so that process conditions corresponding to each gate can be adjusted independently. This allows for great flexibility in the control of injection molding to produce complex, high-quality parts.

Kazmer, David O. (San Francisco, CA)

1996-09-17

40

Injection molding of bushes made of tribological PEEK composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Polyetheretherketone (PEEK) composites have been extensively studied because of the excellent tribological behavior among plastics. However, laboratory specimens and tests are generally discussed, whereas application studies on industrial components are infrequent. In this paper, an injection molded...

 
 
 
 
41

Binder Removal from Powder Injection Molded 316L Stainless Steel  

Directory of Open Access Journals (Sweden)

Full Text Available This study reports the results of preparation of 316L stainless steel polymer based injection molded feed stock, rheology of feed stock and injection molding. The plastic binder was extracted from molded samples. The binder extraction was carried out in two steps: by solvent and thermal techniques. The results showed that feed stock prepared was suitable for injection molding and this was confirmed by rheology data measured by using capillary rheometer. The test samples were injection molded without physical defects. Paraffin Wax (major binder) was extracted by using solvent extraction for 300 min. The thermal debinding was performed four different heating rates rage 1-7C min-1. The SEM results showed that the PW was completely extracted from the test samples after 300 min.

Muhammad Rafi Raza; Faiz Ahmad; M.A. Omar; R.M. German

2011-01-01

42

Modelling and monitoring in injection molding  

DEFF Research Database (Denmark)

This thesis is concerned with the application of statistical methods in quality improvement of injection molded parts. The methods described are illustrated with data from the manufacturing of parts for a medical device. The emphasis has been on the variation between cavities in multi-cavity molds. >From analysis of quality measurements from a longer period of manufacturing, it was found that differences in cavities was that source of variation with greatest influence on the lenght of the molded parts. The other large contribution to the lenght varation was the different machine settings. Samples taken within the same machine set-point did not cause great variation compared to the two preceding sources of variation. A simple graphical approach is suggested for finding patterns in the cavity differences. Applying this method to data from a 16 cavity mold, a clear connection was found between a parts lenght and the producing cavitys position in the mold. In a designed expriment it was possible to isolate the machine parameters contributing to the variation beteeen cavities. Thus, with a proper choice of levels for the machine variables, it was possible to reduce the varation between cavities substantially. Also an alternative model for the shrinkage of parts from a multi-cavity mold is suggested. From applying the model to data from a shringage study, it seemed that the observed part differences were not only due to differences in cavity dimensions. A model for the in-control varation for a multi-cavity molding process was suggested. Based on this model, control charting proceures have been suggested for monitoring the quality of the molded parts. Moreover, a capability index for multi-cavity molds has been suggested. Furthermore an alternative method for in-line quality charting is suggested. The method is for continuous control by attributes, and it is an alternative to the batch oriented approach mostly used. The procedure is especially efficient for quality requirements of very low proportion non-conformities. For the proposed charts the ARL function is derived. It is shown that in the case where a non-conforning unit is only expected very rarely during sampling, a moving sum chart and a CUSUM chart are equivalent. Finally, the correlation structure of 21 process variables has been studied prior to monitoring the process. Is is illustrated how the process can be analysed with multivariate techniques. It was found that two principal components reflected changes in machine set-points. Thus, there seems to be great potential in monitoring the process variables using a multivariate approach.

Thyregod, Peter

2001-01-01

43

Study on heat flux from resin to mold in injection molding process  

Energy Technology Data Exchange (ETDEWEB)

Recently, an injection molding of thermoplastic is widely used in many industries, because this manufacturing method is very suitable for mass production. For injection molding processes, a number of software packages for simulating an injection molding process have been developed. It is assumed in these software packages that the heat transfer coefficient between the resin and the mold surface is constant at the filling or cooling stages. In general, when melted resin flows into the mold, heat is generated in the flowing resin because of the high viscosity at the filling stage. Moreover at the cooling stage, a separation of the molded part from the mold surface generally occurs because of shrinkage of the molded material. Therefore, the heat transfer coefficient has not been accurately obtained yet at these stages. In this paper, the temperature near the surface of the mold cavity has been experimentally measured, so the heat flux that flows from the resin to the mold has been able to be analytically estimated by an inverse conduction method. On the other hand, the separating behavior of the resin from the mold surface has been measured using an ultrasonic transducer attached to the outer surface of the stationary mold. The heat flux that flows from the resin to the mold has been analytically estimated. The apparent heat transfer coefficient can be obtained from the heat flux and the representative temperature difference, which is measured by an ultrasonic technique. It was discovered that the heat flux and the apparent heat transfer coefficient are hardly influenced by the separation.

Nishiwaki, Nobuhiko; Hori, Sankei

1999-07-01

44

The effects of process parameters on injection-molded PZT ceramics part fabrication- compounding process rheology.  

Energy Technology Data Exchange (ETDEWEB)

Solid solutions of lead-based perovskites are the backbone materials of the piezoelectric components for transducer, actuator, and resonator applications. These components, typically small in size, are fabricated from large sintered ceramic slugs using grinding and lapping processes. These operations increase manufacturing costs and produce a large hazardous waste stream, especially when component size decreases. To reduce costs and hazardous wastes associated with the production of these components, an injection molding technique is being investigated to replace the machining processes. The first step in the new technique is to compound an organic carrier with a ceramic powder. The organic carrier is a thermoplastic based system composed of a main carrier, a binder, and a surfactant. Understanding the rheology of the compounded material is necessary to minimize the creation of defects such as voids or cavities during the injection-molding process. An experiment was performed to model the effects of changes in the composition and processing of the material on the rheological behavior. Factors studied included: the surfactant of the organic carrier system, the solid loading of the compounded material, and compounding time. The effects of these factors on the viscosity of the material were investigated.

Halbleib, Laura L.; Yang, Pin; Mondy, Lisa Ann; Burns, George Robert

2005-05-01

45

Injection-molded nanocomposites and materials based on wheat gluten.  

UK PubMed Central (United Kingdom)

This is, to our knowledge, the first study of the injection molding of materials where wheat gluten (WG) is the main component. In addition to a plasticizer (glycerol), 5 wt.% natural montmorillonite clay was added. X-ray indicated intercalated clay and transmission electron microscopy indicated locally good clay platelet dispersion. Prior to feeding into the injection molder, the material was first compression molded into plates and pelletized. The filling of the circular mold via the central gate was characterized by a divergent flow yielding, in general, a stronger and stiffer material in the circumferential direction. It was observed that 20-30 wt.% glycerol yielded the best combination of processability and mechanical properties. The clay yielded improved processability, plate homogeneity and tensile stiffness. IR spectroscopy and protein solubility indicated that the injection molding process yielded a highly aggregated structure. The overall conclusion was that injection molding is a very promising method for producing WG objects.

Cho SW; Gällstedt M; Johansson E; Hedenqvist MS

2011-01-01

46

The manufactoring of a two–layered injection mold by welding  

Directory of Open Access Journals (Sweden)

Full Text Available The article presents the technology of deposit cladding different materials, using the injection molds for thermoplastic as a case study. The aim of the study is to surface weld to the working surface of the mold a different material with corresponding physical properties. Steel (1.1141) and a copper alloy were used as the base, onto which different materials were surface-welded. Tungsten inert gas (TIG) welding was employed to make molds inserts. An analysis of cross-sectioned specimens was made by optical microscopy, and chemical and hardness profiles were measured too. The thermal conductivity of base and cladded layer was also tested. Finally, a thermal fatigue test was employed to investigate the thermal fatigue properties of such surfaces.

A. Košnik; J. Tušek; L. Kosec; T. Muhi?

2011-01-01

47

CENTRAL CONVEYING & AUTO FEEDING SYSTEMS FOR AN INJECTION MOLDING SHOP  

Directory of Open Access Journals (Sweden)

Full Text Available Nowadays injection molding is probably the most important method of Processing of consumer and industrial goods, and is performed everywhere in the world. The developing of injection molding becomes a competition from day to day. This Process now integrated with computer control make the production better in quality and Better quantity. The trends of producing a plastics product in injection molding industries are recently changing from traditional method to using the FEA analysis. For injection molding industries, time and cost is very important aspects to consider because these two aspectswill directly related to the profits at a company. The next issue toconsider, to get the best parameter for the injection molding process, plastics has been waste. Through the experiment, operator will use large amount of plastics material to get the possibly parameters to setup the machine.To produce the parts with better quality and quantity these molding defects are the major obstacles in achieving the targets with quality & quantity. Various defects like Short shot, colour streaks and low productivity rates are associated with the material mixing and feeding as molded plastics are often a blend of two or more materials. Colors (master batch) and other additives are often mixed (blended) with the raw plastic material prior to the molding process in molding plants. So it is very necessary to work out auto blending and auto feeding of plasticgranules to the machine hopper. This paper will cover the studyof automatic blending unit & central conveying system for plasticgranule feeding to machine & will help in optimizing the injection molding process.

Sanjeev Kumar; Ashu Yadav; Prof. Mohd. Parvez

2011-01-01

48

Two component micro injection molding for MID fabrication  

DEFF Research Database (Denmark)

Molded Interconnect Devices (MIDs) are plastic substrates with electrical infrastructure. The fabrication of MIDs is usually based on injection molding and different process chains may be identified from this starting point. The use of MIDs has been driven primarily by the automotive sector, but recently the medical sector seems more and more interested. In particular the possibility of miniaturization of 3D components with electrical infrastructure is attractive. The paper describes possible manufacturing routes and challenges of miniaturized MIDs based on two component micro injection molding and subsequent metallization. The technology will be demonstrated by an industrial component.

Islam, Mohammad Aminul; Hansen, Hans NØrgaard

2009-01-01

49

Process and part filling control in micro injection molding  

DEFF Research Database (Denmark)

The influence of process parameters on ?-injection molding (?IM) and on ?-injection molded parts has been investigated using Design of Experiments. A mold with a sensor applied at injection location was used to monitor actual injection pressure and to determine the cavity filling time. Flow markers position was measured on the polymer ?-parts to evaluate filling behavior of the polymer melt flowing through ?-features. Experimental results obtained under different processing conditions were evaluated to correlate the process parameter levels influence on the selected responses. Results showed that the injection speed in one of the most influencing process parameters on the ?IM process and on the ?-parts filling.

Tosello, Guido; Hansen, Hans NØrgaard

2008-01-01

50

Dynamic of taking out molding parts at injection molding  

Directory of Open Access Journals (Sweden)

Full Text Available Most plastic parts used in automobile production are manufactured by injection molding. Their quality depends also on taking out molding and on the manipulators for it. Task of this contribution is to theoretically describe a transport of molding at taking out after injection molding in relation on its regulation. The following quantities are derived at it: the transition characteristic of the taking out system, the blocking diagram of taking out molding regulation, the amplitude and phase characteristic and the transition characteristic of action quantity at taking out molding regulation.

E. Ragan; J. Dobránsky; P. Baron; M. Ko?iško; J. Svetlík

2012-01-01

51

PHYSICAL PROPERTIES OF EXTRUDED AND INJECTION MOLDED CORN GLUTEN MEAL  

Science.gov (United States)

This study was performed to investigate the compounding of corn gluten meal (CGM) and decanoic acid and to evaluate their mechanical properties. The mixture of CGM and 30% decanoic acid was compounded in a twin screw extruder, followed by injection molding. Scanning electron microscopy (SEM), tens...

52

Fast prototyping of injection molded polymer microfluidic chips  

DEFF Research Database (Denmark)

We present fast prototyping of injection molding tools by the definition of microfluidic structures in a light-curable epoxy (SU-8) directly on planar nickel mold inserts. Optimized prototype mold structures could withstand injection molding of more than 300 replicas in cyclic olefin copolymer (COC) without any signs of failure or release. The key parameters to avoid mold failure are maximum adhesion strength of the epoxy to the nickel insert and minimum interfacial energy of the epoxy pattern to the molded polymer. Optimal molding of microstructures with vertical sidewalls was found for nickel inserts pre-coated by silicon oxide before applying the structured epoxy, followed by coating of the epoxy by a fluorocarbon layer prior to injection molding. Further improvements in the mold stability were observed after homogeneous coating of the patterned epoxy by a second reflowed layer of epoxy, likely due to the resulting reduction in sidewall steepness. We employed the latter method for injection molding bondable polymer microfluidic chips with integrated conducting polymer electrode arrays that permitted the culture and on-chip analysis of cell spreading by impedance spectroscopy.

Hansen, Thomas Steen; Selmeczi, David

2010-01-01

53

Microcellular injection-molding of polylactide with chain-extender  

International Nuclear Information System (INIS)

The effects of adding an epoxy-based chain-extender (CE) on the properties of injection-molded solid and microcellular polylactide (PLA) were studied. PLA and PLA with 8 wt.% CE (PLA-CE) were melt-compounded using a twin-screw extruder. Solid and microcellular specimens were produced via a conventional and microcellular injection-molding process, respectively. Various characterization techniques including gel permeation chromatography, tensile testing and dynamic mechanical analysis, scanning electron microscopy and differential scanning calorimetry were applied to study the molecular weight, static and dynamic mechanical properties, cell morphology, and crystallization behavior, respectively. The addition of CE enhanced the molecular weight but decreased the crystallinity of PLA. The addition of CE also reduced the cell size and increased the cell density. Furthermore, the decomposition temperatures and several tensile properties, including specific strength, specific toughness, and strain-at-break of both solid and microcellular PLA specimens, increased with the addition of CE.

2009-05-05

54

Preparation and Characterization of Copper Feedstock for Metal Injection Molding  

Directory of Open Access Journals (Sweden)

Full Text Available Powder loading is one of the most critical factors which have important influence on metal injection molding processes. In this study, four different loading feedstocks were prepared from gas atomized copper powder with wax-based binders. Mixes of four feedstocks with 2 Vol. % incremental powders loading from 55% to 61 Vol. % were carried out in a Z-blade mixer. The injection molding was carried out at low pressure. A combination of solvent and thermal debinding was used for binder removal from the samples and then the sintering process take place in argon gas at 900°C. It was observed that the feedstock containing 59 Vol. % of copper produce a free defect samples which was selected as the optimum feedstock.

G. Goudah; F. Ahmad; O. Mamat; Mohd. Afian Omar

2010-01-01

55

Packing parameters effect on injection molding of polypropylene nanostructured surfaces  

DEFF Research Database (Denmark)

In today´s industry, applications involving surface patterning of sub-?m to nanometer scale structures have shown a high growth potential. To investigate the injection molding capability of replicating sub-?m surface texture on a large scale area, a 30x80 mm2 tool insert with surface structures having a diameter of 500 nm was employed. The tool insert surface was produced using chemical-based-batch techniques such aluminum anodization and nickel electroplating. During the injection molding process, polypropylene (PP) was employed as material and packing phase parameters (packing time, packing pressure) were investigated. The replicated surface topographies were quantitatively characterized by atomic force microscopy using specific three-dimensional surface parameters and qualitatively inspected by scanning electron microscopy. Results showed that the degree of replication from the tool to the polymer part was mainly influenced by packing pressure level and distance from the gate.

Calaon, Matteo; Tosello, Guido

2012-01-01

56

FPGA-Based Multiprocessor System for Injection Molding Control  

Directory of Open Access Journals (Sweden)

Full Text Available The plastic industry is a very important manufacturing sector and injection molding is a widely used forming method in that industry. The contribution of this work is the development of a strategy to retrofit control of an injection molding machine based on an embedded system microprocessors sensor network on a field programmable gate array (FPGA) device. Six types of embedded processors are included in the system: a smart-sensor processor, a micro fuzzy logic controller, a programmable logic controller, a system manager, an IO processor and a communication processor. Temperature, pressure and position are controlled by the proposed system and experimentation results show its feasibility and robustness. As validation of the present work, a particular sample was successfully injected.

Benigno Muñoz-Barron; Luis Morales-Velazquez; Rene J. Romero-Troncoso; Carlos Rodriguez-Donate; Miguel Trejo-Hernandez; Juan P. Benitez-Rangel; Roque A. Osornio-Rios

2012-01-01

57

FPGA-based multiprocessor system for injection molding control.  

UK PubMed Central (United Kingdom)

The plastic industry is a very important manufacturing sector and injection molding is a widely used forming method in that industry. The contribution of this work is the development of a strategy to retrofit control of an injection molding machine based on an embedded system microprocessors sensor network on a field programmable gate array (FPGA) device. Six types of embedded processors are included in the system: a smart-sensor processor, a micro fuzzy logic controller, a programmable logic controller, a system manager, an IO processor and a communication processor. Temperature, pressure and position are controlled by the proposed system and experimentation results show its feasibility and robustness. As validation of the present work, a particular sample was successfully injected.

Muñoz-Barron B; Morales-Velazquez L; Romero-Troncoso RJ; Rodriguez-Donate C; Trejo-Hernandez M; Benitez-Rangel JP; Osornio-Rios RA

2012-01-01

58

FPGA-based multiprocessor system for injection molding control.  

Science.gov (United States)

The plastic industry is a very important manufacturing sector and injection molding is a widely used forming method in that industry. The contribution of this work is the development of a strategy to retrofit control of an injection molding machine based on an embedded system microprocessors sensor network on a field programmable gate array (FPGA) device. Six types of embedded processors are included in the system: a smart-sensor processor, a micro fuzzy logic controller, a programmable logic controller, a system manager, an IO processor and a communication processor. Temperature, pressure and position are controlled by the proposed system and experimentation results show its feasibility and robustness. As validation of the present work, a particular sample was successfully injected. PMID:23202036

Muñoz-Barron, Benigno; Morales-Velazquez, Luis; Romero-Troncoso, Rene J; Rodriguez-Donate, Carlos; Trejo-Hernandez, Miguel; Benitez-Rangel, Juan P; Osornio-Rios, Roque A

2012-10-18

59

Effects of powder characteristics on injection molding and burnout cracking  

Energy Technology Data Exchange (ETDEWEB)

Silicon nitride particle size and size distributions were varied widely to determine their effects on burnout cracking of injection-molded test parts containing thick and thin sections. Elimination of internal cracking required significant burnout shrinkage, which did not occur by changes of particle size and size distribution. However, isopressing of test parts after burnout provided the dimensional shrinkage necessary for producing crack-free components.

Bandyopadhyay, G.; French, K.W. (GTE Lab. Inc., Waltham, MA (United States))

1994-03-01

60

CAE for Injection Molding - Past, Present and the Future  

Science.gov (United States)

It is well known that injection molding is the most effective process for mass-producing discrete plastic parts of complex shape to the highest precision at the lowest cost. However, due to the complex property of polymeric materials undergoing a transient non-isothermal process, it is equally well recognized that the quality of final products is often difficult to be assured. This is particularly true when a new mold or material is encountered. As a result, injection molding has often been viewed as an art than a science. During the past few decades, numerical simulation of injection molding process based on analytic models has become feasible for practical use as computers became faster and cheaper continually. A research effort was initiated at the Cornell Injection Molding Program (CIMP) in 1974 under a grant from the National Science Foundation. Over a quarter of the century, CIMP has established some scientific bases ranging from materials characterization, flow analysis, to prediction of part quality. Use of such CAE tools has become common place today in industry. Present effort has been primarily aimed at refinements of many aspects of the process. Computational efficiency and user-interface have been main thrusts by commercial software developers. Extension to 3-dimensional flow analysis for certain parts has drawn some attention. Research activities are continuing on molding of fiber-filled materials and reactive polymers. Expanded molding processes such as gas-assisted, co-injection, micro-molding and many others are continually being investigated. In the future, improvements in simulation accuracy and efficiency will continue. This will include in-depth studies on materials characterization. Intelligent on-line process control may draw more attention in order to achieve higher degree of automation. As Internet technology continues to evolve, Web-based CAE tools for design, production, remote process monitoring and control can come to path. The CAE tools will eventually be integrated into an Enterprise Resources Planning (ERP) system as the trend of enterprise globalization continues.

Wang, Kuo K.

2004-06-01

 
 
 
 
61

Injection molding of high aspect ratio sub-100 nm nanostructures  

DEFF Research Database (Denmark)

We have explored the use of mold coatings and optimized processing conditions to injection mold high aspect ratio nanostructures (height-to-width >1) in cyclic olefin copolymer (COC). Optimizing the molding parameters on uncoated nickel molds resulted in slight improvements in replication quality as described by height, width and uniformity of the nanoscopic features. Use of a mold temperature transiently above the polymer glass transition temperature (Tg) was the most important factor in increasing the replication fidelity. Surface coating of the nickel molds with a fluorocarbon-containing thin film (FDTS) greatly enhanced the quality of replicated features, in particular at transient mold temperatures above Tg. Injection molding using the latter mold temperature regime resulted in a bimodal distribution of pillar heights, corresponding to either full or very poor replication of the individual pillars. The poorly replicated structures on nickel molds with or without FDTS coatings all appeared fractured. We investigated the underlying mechanism in a macroscopic model system and found reduced wetting and strongly decreased adhesion of solidified COC droplets on nickel surfaces after coating with FDTS. Reduced adhesion forces are consistent with lowered friction that reduces the risk of fracturing the nanoscopic pillars during demolding. Optimized mold surface chemistry and associated injection molding conditions permitted the fabrication of square arrays of 40 nm wide and 107 nm high (aspect ratio >2.5) pillars on a 200 nm pitch.

Matschuk, Maria; Larsen, Niels B

2013-01-01

62

A Recurrent Neural Network for Warpage Prediction in Injection Molding  

Directory of Open Access Journals (Sweden)

Full Text Available Injection molding is classified as one of the most flexible and economical manufacturing processes with high volumeof plastic molded parts. Causes of variations in the process are related to the vast number of factors acting during aregular production run, which directly impacts the quality of final products. A common quality trouble in finishedproducts is the presence of warpage. Thus, this study aimed to design a system based on recurrent neural networksto predict warpage defects in products manufactured through injection molding. Five process parameters areemployed for being considered to be critical and have a great impact on the warpage of plastic components. Thisstudy used the finite element analysis software Moldflow to simulate the injection molding process to collect data inorder to train and test the recurrent neural network. Recurrent neural networks were used to understand the dynamicsof the process and due to their memorization ability, warpage values might be predicted accurately. Results show thedesigned network works well in prediction tasks, overcoming those predictions generated by feedforward neuralnetworks.

A. Alvarado-Iniesta; D.J. Valles-Rosales; J.L. García-Alcaraz; A. Maldonado-Macias

2012-01-01

63

Injection molding of high aspect ratio sub-100 nm nanostructures  

Science.gov (United States)

We have explored the use of mold coatings and optimized processing conditions to injection mold high aspect ratio nanostructures (height-to-width >1) in cyclic olefin copolymer (COC). Optimizing the molding parameters on uncoated nickel molds resulted in slight improvements in replication quality as described by height, width and uniformity of the nanoscopic features. Use of a mold temperature transiently above the polymer glass transition temperature (Tg) was the most important factor in increasing the replication fidelity. Surface coating of the nickel molds with a fluorocarbon-containing thin film (FDTS) greatly enhanced the quality of replicated features, in particular at transient mold temperatures above Tg. Injection molding using the latter mold temperature regime resulted in a bimodal distribution of pillar heights, corresponding to either full or very poor replication of the individual pillars. The poorly replicated structures on nickel molds with or without FDTS coatings all appeared fractured. We investigated the underlying mechanism in a macroscopic model system and found reduced wetting and strongly decreased adhesion of solidified COC droplets on nickel surfaces after coating with FDTS. Reduced adhesion forces are consistent with lowered friction that reduces the risk of fracturing the nanoscopic pillars during demolding. Optimized mold surface chemistry and associated injection molding conditions permitted the fabrication of square arrays of 40 nm wide and 107 nm high (aspect ratio >2.5) pillars on a 200 nm pitch.

Matschuk, Maria; Larsen, Niels B.

2013-02-01

64

Respiratory symptoms associated with the use of azodicarbonamide foaming agent in a plastics injection molding facility.  

UK PubMed Central (United Kingdom)

Respiratory health variables were studied cross-sectionally in 227 employees of a plastics molding facility where numerous complaints had been apparently associated with the use of azodicarbonamide foaming agent in injection molding. Pre- and postshift respiratory status measures and azodicarbonamide concentrations were also obtained for 17 employees. Cross-sectional pulmonary function differences by injection molding status were not observed. Modest decrements in pulmonary function measures were observed between start and end of shift but with no dose-effect relationship. A strong association was observed for injection molding workers for eye/nose/throat irritation, cough, and wheezing. Additionally, wheezing, chest tightness, and symptoms of chronic bronchitis were strongly associated with work in injection molding during periods in which azodicarbonamide was in use. These results suggest respiratory symptom causation by some combination of azodicarbonamide itself, reaction products of azodicarbonamide formed during injection molding, or other unidentified agents uniquely associated with the process of injection molding with azodicarbonamide foaming agent.

Whitehead LW; Robins TG; Fine LJ; Hansen DJ

1987-01-01

65

Respiratory symptoms associated with the use of azodicarbonamide foaming agent in a plastics injection molding facility.  

Science.gov (United States)

Respiratory health variables were studied cross-sectionally in 227 employees of a plastics molding facility where numerous complaints had been apparently associated with the use of azodicarbonamide foaming agent in injection molding. Pre- and postshift respiratory status measures and azodicarbonamide concentrations were also obtained for 17 employees. Cross-sectional pulmonary function differences by injection molding status were not observed. Modest decrements in pulmonary function measures were observed between start and end of shift but with no dose-effect relationship. A strong association was observed for injection molding workers for eye/nose/throat irritation, cough, and wheezing. Additionally, wheezing, chest tightness, and symptoms of chronic bronchitis were strongly associated with work in injection molding during periods in which azodicarbonamide was in use. These results suggest respiratory symptom causation by some combination of azodicarbonamide itself, reaction products of azodicarbonamide formed during injection molding, or other unidentified agents uniquely associated with the process of injection molding with azodicarbonamide foaming agent. PMID:3812500

Whitehead, L W; Robins, T G; Fine, L J; Hansen, D J

1987-01-01

66

On the Injection Molding of Nanostructured Polymer Surfaces  

DEFF Research Database (Denmark)

Well-defined nano-topographies were prepared by electron-beam lithography and electroplated to form nickelshims. The surface pattern consisted of square pillars repeated equidistantly within the plane of the surface in a perpendicular arrangement. The width and distance between the squares both ranged from 310 to 3100 rim. All the pillars were 220 nm high. The nickel-shim was used as a surface-template during injection molding of polycarbonate. Secondly, a nickel shim, with a surface pattern consisted of a squared sine with a period of 700 nm and amplitude of 450 nm, was mounted on, and it was in good thermal contact with the upper plate in a hot-press. Polycarbonate/polystyrene was melted on the lower plate while the temperature of the shim was kept below the glass transition temperature. The upper plate was lowered until the shim was in contact with the melt. Experiments were carried out with a clean shim and a shim coated with a monolayer of fluorocarbonsilane. As a result of the surface coating, the amplitude of the replicated grating decreased from about 350 nm in polycarbonate and 100 nm in polystyrene to less than 10 nm. The experiments strongly suggest that the possibility to injection mold sub-micrometer surface structures in polymers mainly relates to adhesive energy between polymer and shim.

Pranov, Henrik; Rasmussen, Henrik K.

2006-01-01

67

Stability of FDTS monolayer coating on aluminum injection molding tools  

DEFF Research Database (Denmark)

The injection molding industry often employs prototype molds and mold inserts from melt spun (rapid solidification processing [1,2]) aluminum, especially for applications in optics [3,4], photonics [5] and microfludics. Prototypes are also used for verification of mold filling. The use of aluminum tools has reduced lead time (days instead of weeks) and manufacturing cost (30% of conventional mold). Moreover, for aluminum, a surface roughness (RMS) below 5 nm can be obtained with diamond machining [3,4,6]. Conventional mold coatings add cost and complexity, and coatings with thicknesses of a few microns can obliterate small features. The nanoimprint lithography community extensively uses functional monolayer coatings on silicon/SiO2 lithographic stamps [7–11]. This treatment dramatically reduces stiction, and improves yield and quality of replicated nanostructures. Here we report on a fluorinated trichloro-silane based coating deposited on aluminum or its alloys by molecular vapor deposition. Wehave tested the stability of this coating in challenging conditions of injection molding, an environment with high shear stress from the molten polymer, pressures up to 200 MPa, temperatures up to 250 ?C, and rapid thermal cycling.

Cech, Jiri; Taboryski, Rafael J.

2012-01-01

68

Viscosity and powder dispersion in ceramic injection molding mixtures  

Energy Technology Data Exchange (ETDEWEB)

Particle dispersion in ceramic injection molding mixtures is investigated from the shear viscosity data of the mixtures. The degree of agglomeration of the mixture is examined using the Krieger and Dougherty equation on the viscosity for a concentrated suspension. The number of particles in a single agglomerate is evaluated by the shape factor parameter of suspended particles in the Krieger and Dougherty model with the scaling law of fractal analysis on particle agglomerates. The number of particles per agglomerate predicted are four particles for a zirconia sample, and for a alumina sample the particles are in a well dispersed state. These values of agglomeration in the molding mixtures predicted by the viscometric method are almost consistent with those predicted by the visualized technique. (author)

Okada, K.; Nagase, Y. [Kurashiki Univ. of Science and the Arts, Okayama (Japan). Dept. of Chemical Tech.

2000-02-01

69

Simulation of infrared rapid surface heating for injection molding  

Energy Technology Data Exchange (ETDEWEB)

In this study, a three-dimension ray tracing and transient thermal simulation is developed to evaluate the thermal condition of injection mold surface with infrared surface rapid heating system. Several types of reflectors were applied to study the heating ability of the rapid surface heating system. A commercial available optical analysis program, TracePro, was used to simulate the infrared absorption of the mold surface. The surface temperature of the mold insert was evaluated by 2D and 3D transient thermal analysis with a commercial software, ANSYS. The results from simulation and thermal video measurement system agree well. Besides, the temperature distribution of the mold surface can be better observed via the 3D thermal analysis developed in this article. (author)

Chang, Pei-Chi; Hwang, Sheng-Jye [Room 905, Department of Mechanical Engineering, National Cheng Kung University, No. 1, University Road, Tainan 701 (China)

2006-10-15

70

Improving energy savings on injection molding machines through microcomputers  

Energy Technology Data Exchange (ETDEWEB)

The need for energy efficiency on plastic injection molding machines has generated an increased awareness of the machine hydraulic system's potential energy losses. First, it must be understood how a particular machine is being used. After this evaluation, an energy efficient hydraulic system can be designed by using a microcomputer to analyze the energy usage for a particular molding operation. The modified, energy saving pumping system is a digital flow system which is controlled by a programmable controller interfaced with the original machine controller. The objective is to apply the most desirable hydraulic system while not losing sight of the other important criteria that the molder must have for overall machine productivity -- molding flexibility or utilization of the overall machine range; durability and low maintenance; quiet operation; and economic payback of the hydraulic system employed.

Moorhead, J.R.

1983-12-01

71

Evaluation of stability for monolayer injection molding tools coating  

DEFF Research Database (Denmark)

We tested and characterized molecular coating of Aluminium and Nickel prototype molds and mold inserts for polymer replication via injection molding (IM). X-Ray photoelectron spectroscopy (XPS) data, sessile drop contact angles with multiple fluids, surface energy and roughness data have been collected and used to predict coating lifetimes. Samples have been characterized immediately after coating, after 500+ IM cycles to test durability and after 7 months to test temporal stability. Sessile drop contact angle was measured for multiple fluids, namely water, di-iodomethane and benzylacohol. Detectable coating presence was indicated by an increased angle on all post IM samples. To conclude, we present mold coating evaluation method, which is well suited for ultrathin, controlable, covalently bonded coating, that is reasonably durable, affordable, scalable to production, detectable on surface and especially suitable for rapid prototyping and mold geometry testing.

Cech, Jiri; Taboryski, Rafael J.

2012-01-01

72

Finite Element Analysis of Reciprocating Screw for Injection Molding Machine  

Directory of Open Access Journals (Sweden)

Full Text Available This paper deals with, the solution of problem occurred for reciprocating screw of Injection molding machine. It identifies and solves the problem by using the modeling and simulation techniques. The problem occurred in the reciprocating screw of machine which was wearing of threads due to affect of temperature of mold materials(flow materials) i.e. Nylon, low density polypropylene, polystyrene, PVC etc., The main work was to model the components of machine with dimensions, assemble those components and then simulate the whole assembly for rotation of the screw. The modeling software used is PRO-E wildfire 4.0 for modeling the machine components like body, movable platen, fixed platen, barrel, screw, nozzle, etc. The analysis software ANSYS is used to analyze the reciprocating screws. The objectives involved are:- • To model all the components using modeling software Pro-E 4.0 • To assemble all the components of the machine in the software. • To make the assembly run in Pro-E software.• Analysis of screw of machine using Ansys 11.0 software. • To identify the wearing of threads and to provide the possible solutions.This problem is major for all industrial injection molding machines which the industries are facing and they need the permanent solution, so if the better solution is achieved then the industries will think for implementing it. The industries are having temporary solution but it will affect the life of the screw, because the stresses will be more in machined screw on lathe machine as compared to normal screw. Also if the screw will fail after some years of operation, the new screw available in the market will have the same problem. Also the cost associated with new screw and its mounting is much more as it is the main component of machine.

Nagsen B. Nagrale; Dr.R.N.Baxi

2011-01-01

73

Quality Prediction Model of Injection-Molded Rib Design using Back-Propagation Network  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, an analytical model of a rectangular thermoplastic ABS (Acrylonitrile Butadiene Styrene) plastic cover with rib of a given thickness (2.8 mm) was introduced and the dimensions as well as width of the rib were selected as the control factors for simulation. Additionally, the deflection under a constant force of 150 Newton at the back centre of the cover was defined as quality characteristic. Moreover, the L9(34) orthogonal array for four factors and three levels from Taguchi method was additionally considered to layout the 34 = 81 sets of full simulations. By commencing the BPN (Back-Propagation Network) to learn the selected 45 sets of simulated results. The remaining 36 sets of simulated results are then employed to verify and construct a quality predictor of rib design. Considering the learning rate as 1 and momentum factor as 0.5, the results of 20000 times of BPN training through a hidden layer indicated that the accuracy of deflection prediction reached 95.87%. In this study, the full FEM (Finite Element Method) simulated results from the 81 sets of combinations layout by Taguchi method are learned and verified by BPN for the design of injection-molded rib. It is shown that the quality of a plastic rib can surely be effectively found with the proposed economic and prospective BPN. This study exactly contributes an economical technique to the quality prediction of rib design for plastic injection industry in minimizing the development period of a new product.

Tian-Syung Lan; Ming-Yung Wang

2009-01-01

74

Fabrication of Composite Material Using Gettou Fiber by Injection Molding  

Science.gov (United States)

This study investigated the mechanical properties of composite using gettou (shell ginger) fiber as reinforcement fabricated from injection molding. Gettou fiber is a natural fiber made from gettou, a subtropical plant that is largely abundant in Okinawa, Japan. We used the stem part of gettou plant and made the gettou fiber by crushing the stem. The composite using gettou fiber contributed to low shrinkage ratio, high bending strength and high flexural modulus. The mechanical strength of composite using long gettou fiber showed higher value than composite using short gettou fiber. Next, because gettou is particularly known for its anti-mold characteristic, we investigated the characteristic in gettou plastic composite. The composite was tested against two molds: aspergillius niger and penicillium funiculosum. The 60% gettou fiber plastic composite was found to satisfy the JISZ2801 criterion. Finally, in order to predict the flexural modulus of composite using gettou fiber by Halpin-Tsai equation, the tensile elastic modulus of single gettou fiber was measured. The tendency of the experimental results of composite using gettou fiber was in good agreement with Halpin-Tsai equation.

Setsuda, Roy; Fukumoto, Isao; Kanda, Yasuyuki

75

Three dimensional modeling of metal powder injection molding  

International Nuclear Information System (INIS)

In this work, a three-dimensional transient finite element flow analysis code is used to solve powder injection molding problems. Free surface, non-isothermal flow solutions are obtained by solving the momentum, mass and energy equations. An additional transport equation is solved for the front tracking function indicating the flow front position. The flow of 17-4 stainless steel powder with a water-soluble binder is simulated in a thick three-dimensional part with a diaphragm gate. The compound used is very sensitive to thermal effects because of its high thermal diffusivity and highly sensitive temperature dependence of the viscosity. The simulation predicted several unusual experimentally observed flow patterns: bypass flow (flow external and/or internal to the initial annular flow) and nonuniform flow (nonaxisymmetric flow in a preferred direction through the diaphragm gate). The work considers the effect of filling time, melt/mold temperature, inertia, yield stress, and wall slip on flow patterns, in order to identify the processing conditions that separate regions of uniform and nonuniform flow. (author)

2000-01-01

76

Three dimensional modeling of metal powder injection molding  

Energy Technology Data Exchange (ETDEWEB)

In this work, a three-dimensional transient finite element flow analysis code is used to solve powder injection molding problems. Free surface, non-isothermal flow solutions are obtained by solving the momentum, mass and energy equations. An additional transport equation is solved for the front tracking function indicating the flow front position. The flow of 17-4 stainless steel powder with a water-soluble binder is simulated in a thick three-dimensional part with a diaphragm gate. The compound used is very sensitive to thermal effects because of its high thermal diffusivity and highly sensitive temperature dependence of the viscosity. The simulation predicted several unusual experimentally observed flow patterns: bypass flow (flow external and/or internal to the initial annular flow) and nonuniform flow (nonaxisymmetric flow in a preferred direction through the diaphragm gate). The work considers the effect of filling time, melt/mold temperature, inertia, yield stress, and wall slip on flow patterns, in order to identify the processing conditions that separate regions of uniform and nonuniform flow. (author)

Ilinca, F.; Hetu, J-F.; Derdouri, A. [National Research Council of Canada, Industrial Material Inst., Boucherville, Quebec (Canada); Holmes, B. [Columbia Powder Injection Molding, Surrey, British Columbia (Canada); Scott, C.; Stevenson, J. [Honeywell PowerFlo Technologies, Morristown, New Jersey (United States)

2000-07-01

77

Predictive Engineering Tools for Injection-Molded Long-Carbon-Fiber Thermoplastic Composites  

Energy Technology Data Exchange (ETDEWEB)

This quarterly report summarizes the status for the project planning to complete all the legal and contract documents required for establishing the subcontracts needed and a Cooperative Research and Development Agreement (CRADA) with Autodesk, Inc., Toyota Motor Engineering and Manufacturing North America (Toyota), and Magna Exterior and Interiors Corporation (Magna). During the second quarter (1/1/2013 to 3/31/2013), all the technical and legal documents for the subcontracts to Purdue University, University of Illinois, and PlastiComp, Inc. were completed. The revised CRADA documents were sent to DOE, Autodesk, Toyota, and Magna for technical and legal reviews. PNNL Legal Services contacted project partners’ Legal counterparts for completing legal documents for the project. A non-disclosure agreement was revised and sent to all the parties for reviews.

Nguyen, Ba Nghiep; Simmons, Kevin L.

2013-05-30

78

Predictive Engineering Tools for Injection-Molded Long-Carbon-Fiber Thermoplastic Composites - Quarterly Report  

Energy Technology Data Exchange (ETDEWEB)

This quarterly report summarizes the status for the project planning to initiate all the legal and contract documents required for establishing the subcontracts needed and a Cooperative Research and Development Agreement (CRADA) with Autodesk, Inc., Toyota Motor Engineering and Manufacturing North America (Toyota), and Magna Exterior and Interiors Corporation (Magna). During the first quarter (10/1/2012 to 12/31/2012), the statements of work (SOW) for the subcontracts to Purdue University, University of Illinois, and PlastiComp, Inc. were completed. A draft of the CRADA SOW was sent to Autodesk, Toyota, and Magna for technical and legal reviews. PNNL Legal Services contacted project partners’ Legal counterparts for preparing legal documents for the project. A non-disclosure agreement was drafted and sent to all the parties for reviews.

Nguyen, Ba Nghiep; Simmons, Kevin L.

2013-04-04

79

Powder Injection Molding of Al-(Steel and Magnet) Hybrid Components  

Science.gov (United States)

A powder injection molding (PIM) process was developed to prepare aluminum hybrid components incorporating low carbon steel, AlNiCo, or BaFeO magnetic inserts. The inserts were securely bound within the powder injection molded aluminum due to sintering shrinkage and physical reaction at the interface. The low sintering temperature of the aluminum alloy ensured a minimal level of interfacial reaction and limited the degradation of the properties of the inserts.

Liu, Z. Y.; Kent, D.; Schaffer, G. B.

2009-12-01

80

RECENT METHODS FOR OPTIMIZATION OF PLASTIC INJECTION MOLDING PROCESS –A RETROSPECTIVE AND LITERATURE REVIEW  

Directory of Open Access Journals (Sweden)

Full Text Available Injection molding has been a challenging process for many manufacturers and researchers to produce products meeting requirements at the lowest cost. Faced with global competition in injection molding industry, using the trialand- error approach to determine the process parameters for injection molding is no longer good enough. Factors that affect the quality of a molded part can be classified into four categories: part design, mold design, machineperformance and processing conditions. The part and mold design are assumed as established and fixed. During production, quality characteristics may deviate due to drifting or shifting of processing conditions caused by machine wear, environmental change or operator fatigue. Determining optimal process parameter settings critically influences productivity, quality, and cost of production in the plastic injection molding (PIM) industry. Previously, production engineers used either trial-and-error method or Taguchi’s parameter design method to determine optimal process parameter settings for PIM. However, these methods are unsuitable in present PIM because of the increasing complexity of product design and the requirement of multi-response quality characteristics. This article aims to review the recent research in designing and determining process parameters of injection molding. A number of research works based on various approaches have been performed in the domain of the parameter setting for injection molding. These approaches, including mathematical models, Taguchi method, Artificial Neural Networks (ANN),Fuzzy logic, Case Based Reasoning (CBR), Genetic Algorithms (GA), Finite Element Method(FEM),Non Linear Modeling, Response Surface Methodology, Linear Regression Analysis ,Grey Rational Analysis and Principle Component Analysis (PCA) are described in this article. The strength and theweakness of individual approaches are discussed. It is then followed by conclusions and discussions of the potential research in determining process parameters for injection molding.

P.K. Bharti; M. I. Khan,; Harbinder Singh

2010-01-01

 
 
 
 
81

Simulation and measurement of optical aberrations of injection molded progressive addition lenses.  

UK PubMed Central (United Kingdom)

Injection molding is an important mass-production tool in the optical industry. In this research our aim is to develop a process of combining ultraprecision diamond turning and injection molding to create a unique low-cost manufacturing process for progressive addition lenses (PALs). In industry, it is a well-known fact that refractive index variation and geometric deformation of injection molded lenses due to the rheological properties of polymers will distort their optical performance. To address this problem, we developed a method for determining the optical aberrations of the injection molded PALs. This method involves reconstructing the wavefront pattern in the presence of uneven refractive index distribution and surface warpage using a finite element method. In addition to numerical modeling, a measurement system based on a Shack-Hartmann wavefront sensor was used to verify the modeling results. The measured spherocylindrical powers and aberrations of the PALs were in good agreement with the model. Consequently, the optical aberrations of injection molded PALs were successfully predicted by finite element modeling. In summary, it was demonstrated in this study that numerically based optimization for PAL manufacturing is feasible.

Li L; Raasch TW; Yi AY

2013-08-01

82

Comparative Thermal Analysis of Circular and Profiled Cooling Channels for Injection Mold Tools  

Directory of Open Access Journals (Sweden)

Full Text Available Injection Mold Thermal Management is a critical issue in plastic injection molding process and has major effects on production cycle times that is directly linked with cost and also has effects on part quality. For this reason, cooling system design has great significance for plastic products industry by injection molding. It is crucial not only to reduce molding cycle time but also it considerably affects the productivity and quality of the product. The cooling channels in injection molding have circular cross section due to the conventional manufacturing technique of drilling. In Rapid Prototyping and Tooling techniques of fabricating conformal cooling channels, the channel cross section is again circular. In circular channel, there can be a problem that the distance from the edges of channel to the cavity is not constant and it is variable even for conformal channels. This can give problem of not having even heat dissipation. In this study, injection mold designing and thermal simulations were performed and comparison is presented between molds having cooling channels of circular cross section with mold with profiled cross section channels. Thermal analysis and simulations can effectively predict the performance of circular channels as compared to profiled channels. Some concepts are also presented for the manufacturing of molds with circular and profiled channels with the use of metal filled epoxies.

K. Altaf; V.R. Raghavan; A.M.A. Rani

2011-01-01

83

Injection molded superhydrophobic surfaces based on microlithography and black silicon processing  

DEFF Research Database (Denmark)

This work is concerned with the design, development, and testing of nanostructured polymer surfaces with self-cleaning properties that can be manufactured by injection molding. In particular, the superimposed micro- and nanometer length scales of the so-called Lotus effect were investigated in detail with an engineering perspective on choice of materials and manufacturability by injection molding. Microscope slides with superhydrophobic properties were succesfully fabricated. Preliminary results indicate a contact angle increase from 95° for the unstructured polymer to a maximum 150°. The lowest drop roll off angles observed were in the range 1° to 5°.

SØgaard, Emil; Andersen, Nis Korsgaard

2012-01-01

84

Development of the computer-aided process planning (CAPP) system for polymer injection molds manufacturing  

Directory of Open Access Journals (Sweden)

Full Text Available Beginning of production and selling of polymer products largely depends on mold manufacturing. The costs of mold manufacturing have significant share in the final price of a product. The best way to improve and rationalize polymer injection molds production process is by doing mold design automation and manufacturing process planning automation. This paper reviews development of a dedicated process planning system for manufacturing of the mold for injection molding, which integrates computer-aided design (CAD), computer-aided process planning (CAPP) and computer-aided manufacturing (CAM) technologies.

J. Tepi?; V. Todi?; D. Luki?; M. Miloševi?; S. Borojevi?

2011-01-01

85

Properties of high density polyethylene – Paulownia wood flour composites via injection molding  

Science.gov (United States)

Paulownia wood (PW) flour is evaluated as a bio-based fiber reinforcement. Composites of high density polyethylene (HDPE), 25% by weight of PW, and either 0% or 5% by weight of maleated polyethylene (MAPE) were produced by twin screw compounding followed by injection molding. Molded test composite...

86

Carbon Nanotubes Reinforced Copper Matrix Nanocomposites via Metal Injection Molding Technique  

Directory of Open Access Journals (Sweden)

Full Text Available New thermal management solutions are required to provide cost-effective means of dissipating heat from next generation microelectronic devices. In this paper, fabrication of heat sink nanocomposite made of copper reinforced by multiwalled carbon nanotubes up to 10 Vol. % using metal injection molding technique is presented. A mixture of Cu-MWNTs was compounded using internal mixer machine for homogenous dispersion of the solid powder in the binder. To ensure a flow able feedstock during injection molding process, different binder systems and their Cu-MWNTs feedstocks were examined using capillary rheometer machine. In order to avoid binder degradation, TGA test was carried out. The TGA results showed that the processing temperature such as mixing and injection molding should be lower than 170°C. The injection molding was carried out at low pressure. A combination of solvent and thermal debinding was used for binder removal, and then the samples were isothermally sintered at different sintering temperatures (900-1050°C) in argon atmosphere. The results showed that the sintered samples experienced an isotropic shrinkage around 17% with relatively homogeneous dispersion of MWNTs in the copper matrix which is expected to enhance the physical and mechanical properties of the final product.

Ali S. Muhsan; Faiz Ahmad; Norani M. Mohamed; Putri S.M.BT M. Yusoff; M.R. Raza

2012-01-01

87

Injection molding of Y-TZP powders prepared by colloidal processing  

International Nuclear Information System (INIS)

TZP powders containing 3mol% Y2O3 were prepared from ZrOCl2 solution via an aqueous colloidal suspension of ZrO2. Processing variables were optimized to obtain powders suitable for injection molding. Wettability of powders with binders, fluidity of melting compound, removal of binder from green body, and properties of sintered body were investigated.

1991-05-02

88

Dimensional change in complete dentures fabricated by injection molding and microwave processing.  

UK PubMed Central (United Kingdom)

STATEMENT OF PROBLEM: Acrylic resin complete dentures undergo dimensional changes during polymerization. Techniques with injection molding and polymerization and microwave polymerization are reported to reduce these changes and thereby improve clinical fit. These dimensional changes need to be quantified. PURPOSE: The purpose of this study was to compare differences in dimensional changes of simulated maxillary complete dentures during polymerization and storage in water after injection molding and conventional polymerization, or microwave polymerization against a control of conventionally packed and polymerized simulated maxillary complete dentures. MATERIAL AND METHODS: Forty identical maxillary denture bases were prepared in dental wax with anatomic teeth. They were invested and the wax eliminated from the molds. Ten specimens each were randomly assigned to 1 of 4 groups. Group 1 was compression molded and conventionally polymerized; group 2 was injection molded and conventionally polymerized (Success); group 3 was injection molded and microwave polymerized (Acron MC); and group 4 was injection molded and microwave polymerized (Microbase). Intermolar width and changes in vertical dimension of occlusion, were determined after polymerization and after storage in water for 28 days. Measurements in triplicate were made between points scribed on the second molar teeth with a traveling microscope (accurate to 0.005 mm). Vertical dimension of occlusion was measured between points scribed on the upper and lower members of an articulator by use of an internal micrometer (accurate to 0.05 mm). Data were analyzed by use of a 1-way analysis of variance with Tukey post-hoc contrasts (P <.05). RESULTS: Polymerization contractions (intermolar widths) for each group were: group 1, -0.24%; group 2, -0.27%; group 3, -0.35%; and group 4, -0.37%. The Microbase specimens had greater shrinkage than conventionally polymerized specimens, but there were no significant differences between the groups. All injection methods had less postpolymerization increase in vertical dimension of occlusion (0.63 to 0.41 mm) than the conventional Trevalon control (0.74 mm), but only group 4 was significantly different (P<.004). After storage in water for 28 days, all specimens increased in vertical dimension of occlusion (0.10% to 0.16%) from polymerization techniques, but there were no significant differences between groups. CONCLUSION: Within the limitations of this study, injection molding resulted in a slightly less increase of vertical dimension of occlusion than conventional polymerization techniques, the difference being significant for Microbase compared with the conventional Trevalon control.

Keenan PL; Radford DR; Clark RK

2003-01-01

89

Deflectometric analysis of high volume injection molds for production of occupational eye wear.  

UK PubMed Central (United Kingdom)

PURPOSE: Most of the protective eye wear devices currently on the market are manufactured on simple polycarbonate shields, produced by injection molding techniques. Despite high importance of optical quality, injection molds are rarely inspected for surface quality before or during the manufacturing process. Quality degradation is mainly monitored by optical testing of the molded parts. The purpose of this work was to validate a non-contact deflectometric measurement technique for surface and shape analysis of injection molds to facilitate deterministic surface quality control and to monitor minor conformity of the injection mold with the design data. MATERIAL AND METHODS: The system is based on phase-measuring deflectometry with a operating measurement field of 80×80 mm(2) (±18° slope), a lateral resolution of 60?m and a local sensitivity of some nanometers. The calibration was tested with a calibration normal and a reference sphere. The results were crosschecked against a measurement of the same object with a tactile coordinate measuring machine. Eight injection molds for production of safety goggles with radii of +58mm (convex) and -60mm (concave) were measured in this study. The molds were separated into two groups (cavity 1 and 2 of the tool with different polishing techniques) and measured to test whether the measurement tool could extract differences. The analysis was performed on difference height between the measured surface and the spherical model. RESULTS: The device could derive the surface change due to polishing and discriminate between both polishing techniques, on the basis of the measured data. The concave nozzle sides of the first group (cavity 1) showed good shape conformity. In comparison, the nozzle sides of the second group (cavity 2) showed local deviations from design data up to 14.4?m. Local form variations of about 5?m occurred in the field of view. All convex ejector sides of both groups (cavity 1 and 2) showed rotational symmetric errors and the molds were measured in general flatter than design data. CONCLUSION: We applied a deflectometric system for measuring and evaluating specular reflective injection molding tools to optimize the production process of occupational eye wear. The surface quality could be inline monitored in the production processes for actual spectacle models.

Speck A; Zelzer B; Speich M; Börret R; Langenbucher A; Eppig T

2013-10-01

90

New Design and Injection Molding Analysis of a Low Smoke Zero Halogen Cable Trunk  

Directory of Open Access Journals (Sweden)

Full Text Available The traditional production process of a cable trunk is plastic extrusion with PVC or other halogen containing materials. However, they have many disadvantages such as easy burning, producing toxic gases and smokes. A low smoke zero halogen (LSZH) cable trunk was designed and developed in the present study and the injection molding process was adopted to produce the LSZH cable trunk. Numerical simulations were applied to investigate the effects of the important process parameters on the warpage of the cable trunk. Comparing the simulation results under different process conditions and consideration both of the volumetric shrinkage and the total warpage displacement, it is found that the process parameters, including mold temperature 75°C, melt temperature 265°C, injection pressure 190 MPa, packing pressure 152 MPa, cooling water temperature 50°C and injection time 3 s, are the optimal process conditions for the injection molding process of the new designed cable trunk.

Xiaoxun Zhang; Fang Ma; Xia Li

2012-01-01

91

SAXS studies of the injection molding effects on the nanostructure of polyesters. II: polytrimetylene terephthalate (PTT)  

International Nuclear Information System (INIS)

In this work, the nanoperiodicity of some PTT samples, injection molded at different conditions, was evaluated as a function of the thickness of the samples. From the small angle X-ray scattering (SAXS) results, it was possible to observe that, as expected, there is a gradient of the L and lc values found through the thickness of the PTT samples. It was also found that at the center of the PTT sample injection molded at low injection temperature, Ti, the crystallinity degree evaluated previously by wide angle X-ray diffraction (WAXD) is high and the orientation in this region must be also high, because smaller values of L and lC were found at this region of the sample. The opposite trend was found to PBT.(author)

2005-01-01

92

SAXS studies of the injection molding effects on the nanostructure of polyesters. II: polytrimetylene terephthalate (PTT)  

Energy Technology Data Exchange (ETDEWEB)

In this work, the nanoperiodicity of some PTT samples, injection molded at different conditions, was evaluated as a function of the thickness of the samples. From the small angle X-ray scattering (SAXS) results, it was possible to observe that, as expected, there is a gradient of the L and lc values found through the thickness of the PTT samples. It was also found that at the center of the PTT sample injection molded at low injection temperature, Ti, the crystallinity degree evaluated previously by wide angle X-ray diffraction (WAXD) is high and the orientation in this region must be also high, because smaller values of L and l{sub C} were found at this region of the sample. The opposite trend was found to PBT.(author)

Marinelli, Alessandra L. [Universidade Federal de Sao Carlos (UFSCar), Sao Carlos, SP (Brazil). Centro de Caracterizacao e Desenvolvimento de Materiais]. E-mail: alucas@ccdm.ufscar.br; Farah, Marcelo [Braskem S.A., Sao Paulo, SP (Brazil)]. E-mail: marcelo.farah@braskem.com.br; Plivelic, Tomas; Torriani, Iris [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas (Brazil)]. E-mail: tomas@lnls.br; torriani@lnls.br; Bretas, Rosario E.S. [Universidade Federal de Sao Carlos (UFSCar), Sao Carlos, SP (Brazil). Dept. de Engenharia de Materiais. Nucleo de Reologia e Processamento de Polimeros]. E-mail: bretas@power.ufscar.br

2005-07-01

93

SAXS studies of the injection molding effects on the nanostructure of polyesters. I: polybutylene terephthalate (PBT)  

International Nuclear Information System (INIS)

In this work, the nanoperiodicity of some PBT samples, injection molded at different conditions, was evaluated as a function of the thickness of the samples. From the small angle X-ray scattering (SAXS) results, it was possible to observe that, as expected, there is a gradient of the L and lc values found through the thickness of the samples. It was also found that at the center of the PBT sample injection molded at low injection temperature, Ti, the crystallinity degree evaluated previously by wide angle X-Ray diffraction (WAXD) is high. In a previous study it was pointed out that a high orientation process could be present in the center of this sample, increasing the XC evaluated from WAXD. The SAXS results presented here show that this is not the case, because if orientation is high, the value of L at this region of the sample would be smaller. (author)

2005-01-01

94

Multi-scale filling simulation of micro-injection molding process  

Energy Technology Data Exchange (ETDEWEB)

This work proposes a multi-scale simulation method that can simulate filling during the micro-injection molding process. The multiscale simulation is comprised of two steps. In the first step, the macro-scale flow is analyzed using the conventional method. In the second step, the micro-scale simulation is conducted taking the slip and surface tension into consideration to investigate the filling of microcavity. Moreover, a conservative level set method is employed to accurately track the flow front. First, numerical tests have been done for circular micro-channels. The results show that slip and surface tension play important roles in the micro-regime. Second, to verify the multi-scale method, filling of a thin plate with micro-channel patterns has been simulated. The results show that the proposed multi-scale method is promising for micro-injection molding simulations.

Choi, Sung Joo; Kim, Sun Kyoung [Seoul National University of Science and Technology, Seoul (Korea, Republic of)

2011-01-15

95

Performance of powder-injection-molded W-4.9Ni-2.1Fe components  

Science.gov (United States)

A 93 wt% W heavy alloy was injection molded into standard tensile test specimens and kinetic energy penetrators. Due to the relatively high activation energy of flow (124 kJ/mol), the rheological behavior of the molten feedstock was very susceptible to temperature variation. Using die sets with constant-volume die cavities, the tensile test specimens could be formed within a wide working window, whereas the penetrator could not be molded without defects because of different jetting phenomena during molding. The penetrator could be molded successfully using a die set whose die cavity progressively expanded during molding. The parts thus formed could subsequently be processed into intact components with full density and low carbon contents (<100 ppm). Their mechanical properties were comparable to or better than those of conventionally processed tungsten heavy alloys. Additional penetration test results indicated that powder injection molding was a viable route for processing high-performance tungsten heavy alloys.

Zu, Y. S.; Chiou, Y. H.; Lin, S. T.

1996-10-01

96

Powder Injection Molding of Ceria-Stabilized, Zirconia-Toughened Mullite Parts for UAV Engine Components  

Science.gov (United States)

Powder injection molding (PIM) of ceria-stabilized, zirconia-toughened mullite composites were investigated in the present article with the goal of obtaining performance enhancement in complex geometries for energy and transportation applications. A powder-polymer mixture (feedstock) was developed and characterized to determine its suitability for fabricating complex components using the PIM process. Test specimens were injection molded and subsequently debound and sintered. The sintered properties indicated suitable properties for engine component applications used in unmanned aerial vehicles (UAVs). The measured feedstock properties were used in computer simulations to assess the mold-filling behavior for a miniature turbine stator. The results from the measurements of rheological and thermal properties of the feedstock combined with the sintered properties of the ceria-stabilized, zirconia-toughened mullite strongly indicate the potential for enhancing the performance of complex geometries used in demanding operating conditions in UAV engines.

Martin, Renee; Vick, Michael; Enneti, Ravi K.; Atre, Sundar V.

2013-07-01

97

A Simulation Study of Conformal Cooling Channels in Plastic Injection Molding  

Directory of Open Access Journals (Sweden)

Full Text Available In injection molding process, the cooling channel performance is one of the most crucial factors because it has significant effect on both production rate and the quality of the plastic part. In order to reduce the cycle time, and control the uniform distribution of temperature, it is necessary to create conformal cooling channels, which conform to the shape of the mold cavity and core. This paper presents a simulation study of different types of cooling channels in an injection molded plastic part and compares the performance in terms of time to ejectiontemperature, shrinkage, temperature profile, and part warpage to determine which configuration is more appropriate to provide uniform cooling with minimum cycle time. Autodesk Moldflow Insight (AMI) simulation software is used to examine the results of the cooling channels performance.

Omar A. Mohamed, S.H. Masood, Abul Saifullah

2013-01-01

98

Replication of continuous-relief diffractive optical elements by conventional compact disc injection-molding techniques.  

UK PubMed Central (United Kingdom)

Continuous-relief diffractive optical elements have been replicated by use of conventional compact disc injection-molding techniques. Two continuous-relief microstructures, a blazed grating and a fan-out element, were chosen to evaluate the replication process. Original elements were fabricated by direct-write electron-beam lithography. Optical measurements and atomic force microscopy were used for investigating the replication fidelity.

Nikolajeff F; Jacobsson S; Hård S; Billman A; Lundbladh L; Lindell C

1997-07-01

99

Development and evaluation of injection-molded sustained-release tablets containing ethylcellulose and polyethylene oxide.  

UK PubMed Central (United Kingdom)

PURPOSE: It was the aim of the present study to develop sustained-release matrix tablets by means of injection molding of ethylcellulose (EC) and polyethylene oxide (PEO) mixtures and to evaluate the influence of process temperature, matrix composition, and viscosity grade of EC and PEO on processability and drug release. METHODS: Formulations consisting of metoprolol tartrate (MPT, concentration: 30%), EC plasticized by dibutyl sebacate, and PEO were extruded and consequently injection molded into tablets. The influence of process temperature (120°C and 140°C), matrix composition, viscosity grade of EC (4, 10, 20, 45, and 100 mPa·s) and PEO (7 × 10(6), 1 × 10(6), and 1 × 10(5) Mw) on processability and drug release was determined. RESULTS: Formulations consisting of 70% EC and 30% MPT showed incomplete drug release, whereas drug release was too fast for formulations without EC. Higher PEO concentrations increased drug release. Formulations containing 30% metoprolol, EC, and different concentrations of PEO showed first-order release rates with limited burst release. Drug release from direct compressed tablets showed faster drug release rates compared to injection-molded formulations. There was no clear relationship between the molecular weight of EC and drug release. The melting endotherm (113.9°C) of MPT observed in the differential scanning calorimeter thermogram of the tablets indicated that a solid dispersion was formed which was confirmed by X-ray diffractogram. X-ray tomography demonstrated a difference in pore structure between tablets processed at 120°C and 140°C. CONCLUSION: It was concluded that injection molding can be applied successfully to develop sustained-release PEO/EC matrix tablets.

Quinten T; De Beer T; Almeida A; Vlassenbroeck J; Van Hoorebeke L; Remon JP; Vervaet C

2011-02-01

100

Computing flow-induced stresses of injection molding based on PTT model  

Science.gov (United States)

A numerical approach is introduced to solve the viscoelastic flow problem of filling and post-filling in injection molding. The governing equations are in terms of compressible, non-isothermal fluid, and the constitutive equation is based on the PTT model. By introducing some hypotheses according to the characteristics of injection molding, a quasi-Poisson type equation about pressure is derived with part integration. Besides, an analytical form of flow-induced stress is also generalized by using Undermined Coefficient Method. The conventional Galerkin approach is employed to solve the derived pressure equation, and the 'upwind' difference scheme is used to discrete the energy equation. Coupling is achieved between velocity and stress by Super Relax Iteration Method. The flow in the test mold is investigated by comparing the numerical results and photoelastic photos for polystyrene, showing flow-induced stresses are closely related to melt temperatures. The filling of a two-cavity box is also studied to investigate the viscoelastic effects on real injection molding.

Cao, Wei; Gan, Shufeng; Li, Qian; Shen, Changyu

2010-06-01

 
 
 
 
101

The use of stereolithography rapid tools in the manufacturing of metal powder injection molding parts  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english The utilization of stereolithography molds in the manufacture pre-series for injection molded plastic parts aims to reduce costs throughout the product life-time, but mainly during design and manufacturing phases. The use of this Rapid Tooling technique in powder metal injection molding is evaluated in this work. One of the greatest differences between traditional and stereolithography tools is related to the heat conductivity of the materials employed. For example, steel (more) molds have a heat conductivity coefficient 300 times higher than molds made with the photosensitive resin used in the stereolithography process. The discrepancy regarding the cooling rate of the molded parts during the injection cycle must be compensated with adjustments in the injection molding parameters, such as temperature, pressure and speed. The optimization of these parameters made it possible to eject green parts from the mold without causing defects which would become evident in debinding and sintering stages. The dimensional analysis performed at the end of each case study showed that the shrinking factor of the component after the sintering had the same value obtained for components using traditional metallic molds. Moreover, the dimensional error remains under 2% which can be considered low for a pre-series of components (or prototype series).

Beal, V. E.; Ahrens, C. H.; Wendhausen, P. A.

2004-03-01

102

The use of stereolithography rapid tools in the manufacturing of metal powder injection molding parts  

Directory of Open Access Journals (Sweden)

Full Text Available The utilization of stereolithography molds in the manufacture pre-series for injection molded plastic parts aims to reduce costs throughout the product life-time, but mainly during design and manufacturing phases. The use of this Rapid Tooling technique in powder metal injection molding is evaluated in this work. One of the greatest differences between traditional and stereolithography tools is related to the heat conductivity of the materials employed. For example, steel molds have a heat conductivity coefficient 300 times higher than molds made with the photosensitive resin used in the stereolithography process. The discrepancy regarding the cooling rate of the molded parts during the injection cycle must be compensated with adjustments in the injection molding parameters, such as temperature, pressure and speed. The optimization of these parameters made it possible to eject green parts from the mold without causing defects which would become evident in debinding and sintering stages. The dimensional analysis performed at the end of each case study showed that the shrinking factor of the component after the sintering had the same value obtained for components using traditional metallic molds. Moreover, the dimensional error remains under 2% which can be considered low for a pre-series of components (or prototype series).

Beal V. E.; Ahrens C. H.; Wendhausen P. A.

2004-01-01

103

Minimization of sink mark defects in injection molding process – Taguchi approach  

Directory of Open Access Journals (Sweden)

Full Text Available Optimal setting up of injection molding process variables plays a very important role in controlling the quality of the injection molded products. It is all the most important to control attribute defects like sink marks. Sink marks are basically a “designed in” problem and hence it is to be attended during designs stages. Owing to certain conditions and constraints, sometimes, it is rather ignored during design stages and it is expected to be handled by molders with only instruction to ‘do the best’. Handling of numerous processing variables to control defects is a mammoth task that costs time, effort and money. This paper presents a simple and efficient way to study the influence of injection molding variables on sink marks using Taguchi approach. Using the Taguchi approach, optimal parameter settings and the respective sink depth were arrived. The sink depth based on the validation trials was compared with the predicted sink depth and they are found to be in good agreement. The results demonstrate the ability of this approach to predict sink depth for various combination of processing variables with in the design space.

D. Mathivanan; M. Nouby; R. Vidhya

2010-01-01

104

[Application of microwave for dental technique. 5. Injection molding system for resin base denture].  

Science.gov (United States)

An injector and FRP denture flask were developed for injection molding and the fit of the denture base constructed with this injection molding system was evaluated. In addition, the flow and pressure of the dough, that is polymer-monomer mixture, in the mold space were investigated. The monomer of 10 mg/cm2 in the dough vaporized during the 5 minutes it took for the flash to be removed. When pressure of more than 55 kgf/cm2 was exerted to the dough, the dough was completely packed in the mold space. Fastening of the sprue with a bolt within 2 minutes after injection of the dough made the pressure of the dough increase to about 30 kgf/cm2. The dough in the mold space was maintained at a pressure of above 20 kgf/cm2 for microwave heating time. The adaptability of the resin base denture constructed with a combination of injection molding and microwave polymerization was 2 or 3 times greater than that of the denture constructed with microwave heating from the tissue side of the denture base. PMID:2134815

Kimura, H; Teraoka, F; Sugita, M

1990-01-01

105

Development of magnesium semi-solid injection molding; Magnesium han`yoyu shashutsu seikei gijutsu no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

Magnesium semi-solid injection molding is safety and clean process. We have investigated influence of molding conditions on mechanical properties and dimension accuracy of products by semi-solid injection molding. As a result it was proved that the accuracy of products by this process is superior to die casting. This advantage as well as better mechanical properties can be utilized for net shape molding of some automobile parts. 4 refs., 8 figs., 3 tabs.

Sakamoto, K.; Sakate, N.; Ishida, K.; Yamamoto, Y.; Nishimura, K. [Mazda Motor Corp., Hiroshima (Japan)

1997-10-01

106

Linear and volumetric dimensional changes of injection-molded PMMA denture base resins.  

UK PubMed Central (United Kingdom)

OBJECTIVES: The aim of this study was to evaluate the linear and volumetric dimensional changes of six denture base resins processed by their corresponding injection-molding systems at 3 time intervals of water storage. MATERIALS AND METHODS: Two heat-curing (SR Ivocap Hi Impact and Lucitone 199) and four auto-curing (IvoBase Hybrid, IvoBase Hi Impact, PalaXpress, and Futura Gen) acrylic resins were used with their specific injection-molding technique to fabricate 6 specimens of each material. Linear and volumetric dimensional changes were determined by means of a digital caliper and an electronic hydrostatic balance, respectively, after water storage of 1, 30, or 90 days. Means and standard deviations of linear and volumetric dimensional changes were calculated in percentage (%). Statistical analysis was done using Student's and Welch's t tests with Bonferroni-Holm correction for multiple comparisons (?=0.05). RESULTS: Statistically significant differences in linear dimensional changes between resins were demonstrated at all three time intervals of water immersion (p?0.05), with exception of the following comparisons which showed no significant difference: IvoBase Hi Impact/SR Ivocap Hi Impact and PalaXpress/Lucitone 199 after 1 day, Futura Gen/PalaXpress and PalaXpress/Lucitone 199 after 30 days, and IvoBase Hybrid/IvoBase Hi Impact after 90 days. Also, statistically significant differences in volumetric dimensional changes between resins were found at all three time intervals of water immersion (p?0.05), with exception of the comparison between PalaXpress and Futura Gen. SIGNIFICANCE: Denture base resins (IvoBase Hybrid and IvoBase Hi Impact) processed by the new injection-molding system (IvoBase), revealed superior dimensional precision.

El Bahra S; Ludwig K; Samran A; Freitag-Wolf S; Kern M

2013-08-01

107

Cytocompatibility of titanium metal injection molding with various anodic oxidation post-treatments  

International Nuclear Information System (INIS)

Metal injection molding (MIM) is a near net shape manufacturing method that allows for the production of components of small to moderate size and complex shape. MIM is a cost-effective and flexible manufacturing technique that provides a large innovative potential over existing methods for the industry of implantable devices. Commercially pure titanium (CP-Ti) samples were machined to the same shape as a composite feedstock with titanium and polyoxymethylene, and these metals were injected, debinded and sintered to assess comparative biological properties. Moreover, we treated MIM-Ti parts with BIOCOAT®, BIODIZE® and BIOCER®, three different anodic oxidation techniques that treat titanium using acid, alkaline and anion enriched electrolytes, respectively. Cytocompatibility as well as morphological and chemical features of surfaces was comparatively assessed on each sample, and the results revealed that MIM-Ti compared to CP-Ti demonstrated a specific surface topography with a higher roughness. MIM-Ti and BIOCER® samples significantly enhanced cell proliferation, cell adhesion and cell differentiation compared to CP-Ti. Interestingly, in the anodization post-treatment established in this study, we demonstrated the ability to improve osseointegration through anionic modification treatment. The excellent biological response we observed with MIM parts using the injection molding process represents a promising manufacturing method for the future implantable devices in direct contact with bones. - Highlights: ? Metal injection molding technique gives titanium a specific surface roughness. It enhances the biological response. ? Anodic oxidation method adds Ca, P, and Mg ions on the surface, promoting the cell adhesion. ? Cytocompatibility analyses show an increased cell adhesion and proliferation on MIM-Ti compared to pure titanium.

2012-10-01

108

Forehead Augmentation with a Methyl Methacrylate Onlay Implant Using an Injection-Molding Technique.  

UK PubMed Central (United Kingdom)

BACKGROUND: The forehead, which occupies about one third of the face, is one of the major determinants of a feminine or masculine look. Various methods have been used for the augmentation of the forehead using autologous fat grafts or alloplastic materials. Methylmethacrylate (MMA) is the most appropriate material for augmentation of the forehead, and we have used an injection-molding technique with MMA to achieve satisfactory results. METHODS: Under local anesthesia with intravenous (IV) sedation, an incision was made on the scalp and a meticulous and delicate subperiosteal dissection was then performed. MMA monomers and polymers were mixed, the dough was injected into the space created, and manual molding was performed along with direct inspection. This surgery was indicated for patients who wanted to correct an unattractive appearance by forehead augmentation. Every patient in this study visited our clinics 3 months after surgery to evaluate the results. We judged the postoperative results in terms of re-operation rates caused by the dissatisfaction of the patients and complications. RESULTS: During a 13-year period, 516 patients underwent forehead augmentation with MMA. With the injection-molding technique, the inner surface of the MMA implant is positioned close to the underlying frontal bone, which minimizes the gap between the implant and bone. The borders of the implant should be tapered sufficiently until no longer palpable or visible. Only 28 patients (5.4%) underwent a re-operation due to an undesirable postoperative appearance. CONCLUSIONS: The injection-molding technique using MMA is a simple, safe, and ideal method for the augmentation of the forehead.

Park DK; Song I; Lee JH; You YJ

2013-09-01

109

Forehead Augmentation with a Methyl Methacrylate Onlay Implant Using an Injection-Molding Technique  

Science.gov (United States)

Background The forehead, which occupies about one third of the face, is one of the major determinants of a feminine or masculine look. Various methods have been used for the augmentation of the forehead using autologous fat grafts or alloplastic materials. Methylmethacrylate (MMA) is the most appropriate material for augmentation of the forehead, and we have used an injection-molding technique with MMA to achieve satisfactory results. Methods Under local anesthesia with intravenous (IV) sedation, an incision was made on the scalp and a meticulous and delicate subperiosteal dissection was then performed. MMA monomers and polymers were mixed, the dough was injected into the space created, and manual molding was performed along with direct inspection. This surgery was indicated for patients who wanted to correct an unattractive appearance by forehead augmentation. Every patient in this study visited our clinics 3 months after surgery to evaluate the results. We judged the postoperative results in terms of re-operation rates caused by the dissatisfaction of the patients and complications. Results During a 13-year period, 516 patients underwent forehead augmentation with MMA. With the injection-molding technique, the inner surface of the MMA implant is positioned close to the underlying frontal bone, which minimizes the gap between the implant and bone. The borders of the implant should be tapered sufficiently until no longer palpable or visible. Only 28 patients (5.4%) underwent a re-operation due to an undesirable postoperative appearance. Conclusions The injection-molding technique using MMA is a simple, safe, and ideal method for the augmentation of the forehead.

Park, Dong Kwon; Song, Ingook; Lee, Jin Hyo

2013-01-01

110

Electroforming of Tool Inserts for Injection Molding of Optical or Microfluidic Components  

DEFF Research Database (Denmark)

With a rapidly increasing international interest in “Lab-on-a-chip”-systems as well as affordable polymer optics, the combination of electroforming and injection molding offers an attractive fabrication solution. Miniaturized analysis systems can be used for medical, security (anti terror monitoring) and environmental (waste water monitoring) applications. Optical components in polymer materials can be used for consumer electronics and for sensor systems. The presentation will include the complete fabrication scheme for tool inserts based on machining and electroforming. Electroforming processes for nickel and copper will be disclosed. Processing parameters for the different types of tools as well as quality control measures will be presented.

Tang, Peter Torben; Christensen, Thomas R.

2004-01-01

111

Influência do desempenho térmico de moldes fabricados com compósito epóxi/alumínio nas propriedades de pp moldado por injeção/ Thermal behavior of epoxy/aluminum rapid tooling composite during injection molding of polypropylene  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O surgimento das tecnologias de prototipagem rápida (RP) e de ferramental rápido (RT) tem despertado interesse da indústria de moldes de injeção. O vazamento de termofixos com cargas metálicas possibilita a construção de moldes usando materiais compósitos, os quais apresentam maior resistência que os utilizados por outras técnicas RT. Neste trabalho foi estudado o comportamento térmico de moldes fabricados em epóxi/alumínio durante a injeção de polipropile (more) no através de avaliações da estrutura e de propriedades mecânicas utilizando difração de raio X e ensaios de dureza e de tração. Os corpos-de-prova injetados no molde em compósito epóxi/alumínio apresentaram pequenas diferenças no grau de cristalinidade das superfícies analisadas e propriedades mecânicas semelhantes aos corpos-de-prova injetados em molde de aço. O estudo mostrou um razoável desempenho térmico do molde compósito durante a injeção de polipropileno evidenciando a viabilidade de utilização destes moldes na produção de pequenas séries de protótipos e de produtos neste termoplástico. Abstract in english rapid prototyping (RP) and rapid tooling (RT) technologies are gaining increasing importance in the injection molding industry. Casting of resin/metal composites allows the construction of molds with greater resistance than those manufactured by other RT techniques such as Stereolithography. In this work, the thermal behavior of molds manufactured in epoxy/aluminum during the injection molding of polypropylene specimens was investigated. Structural and mechanical characte (more) rization of the molded specimens included X ray analysis, hardness and tensile testing. The samples presented small differences in the degree of crystallinity and similar mechanical properties in comparison with samples injected into steel molds. This study showed a reasonable thermal performance of the epoxy/aluminum mold during the injection molding of polypropylene, thus demonstrating the viability of using these molds to produce a few number of prototypes or products with this thermoplastic.

Salmoria, Gean V.; Ahrens, Carlos H.; Villamizar, Felix A. Y.; Sabino Netto, Aurélio da C.

2008-09-01

112

Influência do desempenho térmico de moldes fabricados com compósito epóxi/alumínio nas propriedades de pp moldado por injeção Thermal behavior of epoxy/aluminum rapid tooling composite during injection molding of polypropylene  

Directory of Open Access Journals (Sweden)

Full Text Available O surgimento das tecnologias de prototipagem rápida (RP) e de ferramental rápido (RT) tem despertado interesse da indústria de moldes de injeção. O vazamento de termofixos com cargas metálicas possibilita a construção de moldes usando materiais compósitos, os quais apresentam maior resistência que os utilizados por outras técnicas RT. Neste trabalho foi estudado o comportamento térmico de moldes fabricados em epóxi/alumínio durante a injeção de polipropileno através de avaliações da estrutura e de propriedades mecânicas utilizando difração de raio X e ensaios de dureza e de tração. Os corpos-de-prova injetados no molde em compósito epóxi/alumínio apresentaram pequenas diferenças no grau de cristalinidade das superfícies analisadas e propriedades mecânicas semelhantes aos corpos-de-prova injetados em molde de aço. O estudo mostrou um razoável desempenho térmico do molde compósito durante a injeção de polipropileno evidenciando a viabilidade de utilização destes moldes na produção de pequenas séries de protótipos e de produtos neste termoplástico.rapid prototyping (RP) and rapid tooling (RT) technologies are gaining increasing importance in the injection molding industry. Casting of resin/metal composites allows the construction of molds with greater resistance than those manufactured by other RT techniques such as Stereolithography. In this work, the thermal behavior of molds manufactured in epoxy/aluminum during the injection molding of polypropylene specimens was investigated. Structural and mechanical characterization of the molded specimens included X ray analysis, hardness and tensile testing. The samples presented small differences in the degree of crystallinity and similar mechanical properties in comparison with samples injected into steel molds. This study showed a reasonable thermal performance of the epoxy/aluminum mold during the injection molding of polypropylene, thus demonstrating the viability of using these molds to produce a few number of prototypes or products with this thermoplastic.

Gean V. Salmoria; Carlos H. Ahrens; Felix A. Y. Villamizar; Aurélio da C. Sabino Netto

2008-01-01

113

Predictive Engineering Tools for Injection-Molded Long-Carbon-Fiber Thermoplastic Composites - FY13 Third Quarterly Report  

Energy Technology Data Exchange (ETDEWEB)

This quarterly report summarizes the status for the project planning to obtain all the approvals required for a Cooperative Research and Development Agreement (CRADA) with Autodesk, Inc., Toyota Motor Engineering and Manufacturing North America (Toyota), and Magna Exterior and Interiors Corporation (Magna). The CRADA documents have been processed by PNNL Legal Services that is also coordinating the revision effort with the industrial parties to address DOE’s comments.

Nguyen, Ba Nghiep; Simmons, Kevin L.

2013-08-06

114

Results on powder injection molding of Ni[sub 3]Al and application to other intermetallic compositions  

Energy Technology Data Exchange (ETDEWEB)

Net forming processes are under development to allow affordable production of intermetallic components. Powder injection molding (PIM) mav be employed for the production of complex-shaped intermetallic geometries. Proper choice of powder parameters and processing conditions can lead to the formation of fullv dense structures through pressure-less sintering. In this study, Ni[sub 3]Al with 0.04 wt.-% boron has been successfully injection molded and sintered to full density. A yield strength of 340 MPa, ultimate tensile strength (UTS) of 591 MPa, and 8% elongation were attained for injection molded and sintered tensile bars. Powder characteristics and sintering behavior are given for the nickel aluminide employed in this study to highlight the powder attributes needed for injection molding. Molding parameters, debinding and sintering schedules, along, with mechanical properties are presented to indicate the viability of PIM for intermetallics. This approach based on the understanding of key powder characteristics and use of the reactive synthesis powder process mav be extended to the successful injection molding of other intermetallic systems.

Cooper, R.M.

1992-01-01

115

Relationship between processing and mechanical properties of injection molded high molecular mass polyethylene + hydroxyapatite composites  

Energy Technology Data Exchange (ETDEWEB)

We apply a macromolecular-orientation approach to produce high molecular weight polyethylene (HMWPE) + hydroxyapatite (HA) ductile composites with the stiffness and strength within the range of human cortical bone. Our composites are produced with different amounts (10 to 50% by weight) of the reinforcement by two procedures: bi-axial rotating drum and twin screw extrusion (TSE). The processing is by conventional injection molding and by Scorim (shear controlled orientation in injection molding) under a wide range of processing windows. Tensile testing is performed and the corresponding performance related to the morphology evaluated by polarized light microscopy and scanning electron microscopy. The control of the processing parameters led to significant improvements of the tensile properties. Compounding by TSE and then processing by Scorim produces the maximum modulus of 7.4 GPa and the ductility as high as 19%, for the HA weight fraction of 30%. These mechanical properties match those of bone, and were obtained with much smaller amounts of HA reinforcement then has been previously reported in literature. Our PE + HA composites present the additional benefit of being ductile even for 50% HA amounts. The use Scorim is a unique way of inducing anisotropy to thick sections and to produce very stiff composites that may be used in biomedical applications with important mechanical loads. This fact, combined with the bioactive behavior of the HA phase, makes our composite usable for orthopedic load-bearing implants. (orig.)

Reis, R.L.; Cunha, A.M.; Oliveira, M.J.; Campos, A.R. [Dept. of Polymer Engineering, University of Minho, Guimaraes (Portugal); Bevis, M.J. [Wolfson Center for Materials Processing, Brunel Univ., Uxbridge (United Kingdom)

2001-04-01

116

Bulk and Surface Molecular Orientation Distribution in Injection-molded Liquid Crystalline Polymers: Experiment and Simulation  

Energy Technology Data Exchange (ETDEWEB)

Bulk and surface distributions of molecular orientation in injection-molded plaques of thermotropic liquid crystalline polymers (TLCPs) have been studied using a combination of techniques, coordinated with process simulations using the Larson-Doi 'polydomain' model. Wide-angle X-ray scattering was used to map out the bulk orientation distribution. Fourier Transform Infrared Attenuated Total Reflectance (FTIR-ATR) and Near-Edge X-ray Absorption Fine Structure (NEXAFS) were utilized to probe the molecular orientation states to within about {approx}5 {micro}m and {approx}2 nm, respectively, of the sample surface. These noninvasive, surface-sensitive techniques yield reasonable self-consistency, providing complementary validation of the robustness of these methods. An analogy between Larson-Doi and fiber orientation models has allowed the first simulations of TLCP injection molding. The simulations capture many fine details in the bulk orientation distribution across the sample plaque. Direct simulation of surface orientation at the level probed by FTIR-ATR and NEXAFS was not possible due to the limited spatial resolution of the simulations. However, simulation results extracted from the shear-dominant skin region are found to provide a qualitatively accurate indicator of surface orientation. Finally, simulations capture the relation between bulk and surface orientation states across the different regions of the sample plaque.

Fang, J.; Burghardt, W; Bubeck, R; Burgard, S; Fischer, D

2010-01-01

117

Optimization of injection molded parts by using ANN-PSO approach  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The aim of the work was the optimization of injection molded product warpage by using an integrated environment.Design/methodology/approach: The approach implemented took advantages of the Finite Element (FE) Analysis to simulate component fabrication and investigate the main causes of defects. A FE model was initially designed and then reinforced by integrating Artificial Neural Network to predict main filling and packing results and Particle Swarm Approach to optimize injection molding process parameters automatically.Findings: This research has confirmed that the evaluation of the FE simulation results through the Artificial Neural Network system was an efficient method for the assessment of the influence of process parameter variation on part manufacturability, suggesting possible adjustments to improve part quality.Research limitations/implications: Future researches will be addressed to the extension of analysis to large thin components and different classes of materials with the aim to improve the proposed approach.Originality/value: The originality of the work was related to the possibility of analyzing component fabrication at the design stage and use results in the manufacturing stage. In this way, design, fabrication and process control were strictly links.

R. Spina

2006-01-01

118

Surface Topographic Characterization for Polyamide Composite Injection Molds Made of Aluminum and Copper Alloys.  

UK PubMed Central (United Kingdom)

In order to ensure flexibility and rapid new product development, the mold industry made use of soft materials for cavity inserts in injection molds. However, materials of this kind are prone to wear. This article analyzes the topographic characterization of the surface and wear processes in injection molds cavities. Two materials have been used to produce the cavities: aluminum alloy EN AW-6082 T4 and copper alloy Cu Zn39 Pb3. The surface topography was measured with the use of optical interferometry profiling technology; roughness and surface parameters were determined according to ISO 4287, ISO 25178, and EUR 15178N. In order to complete this research, an experimental part with different thicknesses and shapes was designed, and cavity inserts of aluminum and copper were made. Polyamide PA6, with 30% fiberglass reinforcement, was employed in the experimental procedure. Measurements of cavity mold surfaces were performed after 9,200 cycles on each mold and at different locations on the mold. The surface measurement was made with a white light vertical scanning interferometry, also known as coherence scanning interferometry (ISO DIS 25178-604). The results are analyzed and differences between the two types of cavity inserts materials are discussed. SCANNING 9999:XX-XX, 2013. © 2013 Wiley Periodicals, Inc.

Pereira A; Hernández P; Martinez J; Pérez JA; Mathia TG

2013-02-01

119

Initial verification of an induction heating set-up for injection molding  

DEFF Research Database (Denmark)

Molding of thin and long parts by injection molding leads to special requirements for the mold in order to ensure proper filling and acceptable cycle time. This paper investigates the applicability of embedded induction heating for the improvement of the filling of thin long parts. The object selected for the investigation is a thin spiral. For the complete molding of the component, elevated mold temperatures are required. For this propose a new injection molding set-up was developed, which allows rapid heating of the cavity wall by an induction heating system. The temperature was measured by two thermocouples placed in the die insert. The system was used to heat up the cavity wall with heating rates of up to 10 °C/s. Experiments were carried out with ABS material. The lengths of the object were measured by a suitable measurement set up. The experimental result show that the use of the induction heating system process is an efficient way for improving the filling of the cavity.

Menotti, Stefano; Hansen, Hans NØrgaard

2013-01-01

120

Micro Machining of Injection Mold Inserts for Fluidic Channel of Polymeric Biochips  

Directory of Open Access Journals (Sweden)

Full Text Available Recently, the polymeric micro-fluidic biochip, often called LOC (lab-on-a-chip), has been focused as a cheap, rapid and simplified method to replace the existing biochemical laboratory works. It becomes possible to form miniaturized lab functionalities on a chip with the development of MEMS technologies. The micro-fluidic chips contain many micro-channels for the flow of sample and reagents, mixing, and detection tasks. Typical substrate materials for the chip are glass and polymers. Typical techniques for micro-fluidic chip fabrication are utilizing various micro pattern forming methods, such as wet-etching, micro-contact printing, and hot-embossing, micro injection molding, LIGA, and micro powder blasting processes, etc. In this study, to establish the basis of the micro pattern fabrication and mass production of polymeric micro-fluidic chips using injection molding process, micro machining method was applied to form micro-channels on the LOC molds. In the research, a series of machining experiments using micro end-mills were performed to determine optimum machining conditions to improve surface roughness and shape accuracy of designed simplified micro-channels. Obtained conditions were used to machine required mold inserts for micro-channels using micro end-mills. Test injection processes using machined molds and COC polymer were performed, and then the results were investigated.

Woo-Chul Jung; Young-Moo Heo; Gil-Sang Yoon; Kwang-Ho Shin; Sung-Ho Chang; Gun-Hee Kim; Myeong-Woo Cho

2007-01-01

 
 
 
 
121

Thermoplastic polyurethanes  

UK PubMed Central (United Kingdom)

Thermoplastic polyurethane for marine and other applications, e.g. seismic tubes or cables, contains a benz-isothiazolinone compound as inhibitor for bacteria, algae and small animals Thermoplastic polyurethanes (TPU) containing compounds (I) with benzisothiazolinone units are new. Thermoplastic polyurethanes (TPU) containing compounds (I) with benzisothiazolinone units are new. Independent claims are also included for (1) mixtures containing TPU as described above and at least one other thermoplastic; (2) seismic tubes and/or cables containing these TPU; (3) a process for the production of TPU by reacting isocyanates with isocyanate-reactive compounds with a mol. wt. of 500-10000 and optionally chain extenders with a mol. wt. of 50-499 in presence of (I) and optionally in presence of catalysts and/or conventional additives etc; and (4) a process for the production of these TPU by mixing TPU with another thermoplastic containing (I).

Brüning Ines Dr.; Harrop Douglas John; Weigelt Gerlinde; Scholz Günter Dr.

122

Heat transfer at the polymer-metal interface -- A method of analysis and its application to injection molding  

Energy Technology Data Exchange (ETDEWEB)

Heat transfer at the polymer-metal interface constitutes a key point to interpret shrinkage and warpage during injection molding. In heat transfer, the interface conditions are modelized by a thermal contact resistance (TCR). An apparatus was built and a new method was used to determine the TCR variation and simultaneously the temperature field in the polymer, in a real situation of injection molding. The experimental device consists in an instrumented injection mold. A specific heat flux sensor has been developed in order to determine simultaneously the metal surface temperature and the heat flux crossing the interface. The polymer surface temperature is obtained by solving numerically the heat conduction equation in the polymer. The boundary conditions are the experimental heat flux densities. The initial condition is evaluated by an inverse method based on the energy conservation and the heat flux history. Two thermal models are necessary to take into account the packing and the cooling phases. Some experimental results will be shown.

Quilliet, S.; Le Bot, P.; Delaunay, D.; Jarny, Y.

1997-07-01

123

Optimizing the Filling Time and Gate of the Injection Mold on Plastic Air Intake Manifold of Engines  

Directory of Open Access Journals (Sweden)

Full Text Available In order to acquire the best filling time, Mold trial is made by setting different injection time, or Mold flow software is used to analyze data recorded by computer. Whether doing successive trials or being simulated point by point, is very tedious. A new method is put forward-seeking the minimum of curve being simulated by Lagrange interpolation. The minimum of the curve is the best filling time. This method can improve the efficiency of the simulation analysis. The software Mold flow provides the possibility to simulate the flow processes of plastic air intake manifold with different gate location and number of injection mold and to predict the position of air traps and weld lines. The location and number of the gate in injection mold are determined by comparing analysis results and avoid mold adjustment and mold repairing. Finished injection mold of plastic air intake manifold on basis of simulation is perfect.

Shiqiang Zhang

2013-01-01

124

Intraoral dental radiographic film packet with thermoplastic comfort enhancing integrated frame  

UK PubMed Central (United Kingdom)

An intraoral x-ray film packet is taught which includes a molded thermoplastic frame (preferably injection molded) to which an x-ray dental packet is sealed. The sealing method can be any one of a number of processes including, but not limited to RF sealing, induction heat sealing, or ultrasonic sealing, as well as using any one of various adhesives to affix the x-ray dental packet to the frame. The injection molded thermoplastic frame provides a cushion to buffer and a soft rounded edge to mask the sharp edges that occur on plastic encased x-ray dental packets. Sealing of the injection molded thermoplastic frame to the x-ray dental packet during manufacture results in a packet which includes a comfort enhancing perimeter frame permanently integrated therewith. In such manner, the dental film packet is manufactured with an integrally formed perimetric cushion. The dental film packet is preferably formed with an outer envelope wherein one of the opposing outer sheets is more rigid than the other. In this way, the laminated perimetric edge formed to bond the two outer sheets together is generally coplanar with the more rigid of the two outer sheets. This resultant planar surface on one side of the packet aids in the accurate positioning of the packet into the frame and further enhances the ability to die cut the packet and maintain outside dimension tolerances.

BACCHETTA RICHARD W; SCHWALLIE SCOTT H; HE FUGUI

125

Study of soft magnetic iron cobalt based alloys processed by powder injection molding  

International Nuclear Information System (INIS)

As a near net shape process, powder injection molding (PIM) opens new possibilities to process Fe-Co alloys for magnetic applications. Due to the fact that PIM does not involve plastic deformation of the material during processing, we envisioned the possibility of eliminating vanadium (V), which is generally added to Fe-Co alloys to improve the ductility in order to enable its further shaping by conventional processes such as forging and cold rolling. In our investigation we have found out two main futures related to the elimination of V, which lead to a cost-benefit gain in manufacturing small magnetic components where high-saturation induction is needed at low frequencies. Firstly, the elimination of V enables the achievement of much better magnetic properties when alloys are processed by PIM. Secondly, a lower sintering temperature can be used when the alloy is processed starting with elemental Fe and Co powders without the addition of V.

2008-01-01

126

An examination of assumptions underlying the state of the art in injection molding modeling  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this paper is to place the modeling assumptions involved in injection molding filling simulation software in context by estimating and comparing the various errors associated with predicting the melt pressure within the cavity during filling. This is achieved by identifying specific sources of modeling, material property, and numerical errors and computing their relative magnitudes through simple scaling, or back-of-an-envelope, calculations. Thereby, the users of such software are provided with useful information for evaluating the expected accuracy of the solutions and for interpreting the output generated. The results presented shed additional light into the black box that mold filling simulations sometimes seem, much in the spirit as have previous examinations of issues such as convergence criteria and mesh density.

Guell, D.C.; Lovalenti, P.M.

1994-12-01

127

Crystallization kinetics and morphology of PBT/MMT and PTT/MMT nanocomposites during injection molding  

International Nuclear Information System (INIS)

This work had as main objective to study the crystallization of nanocomposites of poly(butylene terephthalate) (PBT) and poly(trimethylene terephthalate) (PTT) with a montmorillonite nanoclay (MMT) using an on-line optical monitoring system during the injection molding and to characterize the morphologies of the injection samples by polarized light optical microscopy (PLOM), wide angle X-ray diffraction (WAXS) and differential scanning calorimetry (DSC). The optical system allowed to analyze the crystallization process by the changes of the optical properties during the solidification of the materials. It was concluded that the MMT lamellae accelerated the overall crystallization of the polymers. By PLOM, it was observed that the nanoclay caused qualitative changes on the morphology of the PTT (polymer with slow crystallization kinetics). The crystallinity indexes were not affected by the addition of the MMT; however, by WAXS it was shown that the nanocomposites had a higher orientation degree. (author)

2009-01-01

128

Injection-molded Sm-Fe-N anisotropic magnets using unsaturated polyester resin  

Energy Technology Data Exchange (ETDEWEB)

New injection-molding technology has been developed using an unsaturated polyester (UP) resin in order to produce bonded Sm-Fe-N anisotropic magnets. Sheet magnets of 50 mm x 20 mm x 0.36 mm are successfully made within a cycle time of 90 s. Magnetic properties obtained are almost the same as those obtained in column magnets of {phi}10 mm x 7 mm. Typical data of magnetic properties are as follows: B {sub r} = 0.72 T, H {sub CJ} = 796 kA/m and (BH){sub max} 94.7 kJ/m{sup 3}. The density is 4.79 Mg/m{sup 3}. The degree of orientation of (0 0 6) is 5.31 calculated using the Wilson formula from X-ray diffraction result. Ring magnets of 7.4 mm x 3.2 mm x 0.3 mm are easily made from sheet magnets.

Ohmori, K. [Sumitomo Metal Mining Co. Ltd., 3-18-5 Nakakokubun, Ichikawa, Chiba 272-8588 (Japan)]. E-mail: k_omori@adch.smm.co.jp; Hayashi, S. [Sumitomo Metal Mining Co. Ltd., 3-18-5 Nakakokubun, Ichikawa, Chiba 272-8588 (Japan); Yoshizawa, S. [Sumitomo Metal Mining Co. Ltd., 3-18-5 Nakakokubun, Ichikawa, Chiba 272-8588 (Japan)

2006-02-09

129

Injection-molded Sm-Fe-N anisotropic magnets using unsaturated polyester resin  

International Nuclear Information System (INIS)

New injection-molding technology has been developed using an unsaturated polyester (UP) resin in order to produce bonded Sm-Fe-N anisotropic magnets. Sheet magnets of 50 mm x 20 mm x 0.36 mm are successfully made within a cycle time of 90 s. Magnetic properties obtained are almost the same as those obtained in column magnets of ?10 mm x 7 mm. Typical data of magnetic properties are as follows: B r = 0.72 T, H CJ = 796 kA/m and (BH)max 94.7 kJ/m3. The density is 4.79 Mg/m3. The degree of orientation of (0 0 6) is 5.31 calculated using the Wilson formula from X-ray diffraction result. Ring magnets of 7.4 mm x 3.2 mm x 0.3 mm are easily made from sheet magnets.

2006-02-09

130

Biodegradability of injection molded bioplastic pots containing polylactic acid and poultry feather fiber.  

UK PubMed Central (United Kingdom)

The biodegradability of three types of bioplastic pots was evaluated by measuring carbon dioxide produced from lab-scale compost reactors containing mixtures of pot fragments and compost inoculum held at 58 °C for 60 days. Biodegradability of pot type A (composed of 100% polylactic acid (PLA)) was very low (13 ± 3%) compared to literature values for other PLA materials. Near infrared spectroscopy (NIRS) results suggest that the PLA undergoes chemical structural changes during polymer extrusion and injection molding. These changes may be the basis of the low biodegradability value. Biodegradability of pot types B (containing 5% poultry feather, 80% PLA, 15% starch), and C (containing 50% poultry feather, 25% urea, 25% glycerol), were 53 ± 2% and 39 ± 3%, respectively. More than 85% of the total biodegradation of these bioplastics occurred within 38 days. NIRS results revealed that poultry feather was not degraded during composting.

Ahn HK; Huda MS; Smith MC; Mulbry W; Schmidt WF; Reeves JB 3rd

2011-04-01

131

Injection molding micro patterns with high aspect ratio using a polymeric flexible stamper  

Directory of Open Access Journals (Sweden)

Full Text Available Poor filling occurs during the injection molding process of micro- or nano- scale patterns mainly because the hot polymer melt rapidly cools and its skin quickly solidifies upon contact with the mold surface. In this study, it is proposed to use Polyethylene terephthalate (PET) film coated with patterned polyurethane acrylate (PUA) as an effective thermal barrier. It can significantly hinder heat transfer into the mold during the molding process and thus may keep the melt viscosity low for longer duration. As a result, the replication would be improved not only during the filling phase but also during the packing phase. In order to verify the validity of the use of polymeric stamper, the melt-film interface temperature was evaluated by numerical simulation. Experimental results indicated that patterns possessing widths within the range of one to tens of micrometers and a height of approximately 10 µm were successfully filled and demolded.

2011-01-01

132

The effect of mold surface topography on plastic parat in-process shrinkage in injection molding  

DEFF Research Database (Denmark)

An experimental study of the effect of mold surface roughness on in-process in-flow linear part shrinkage in injection molding has been carried out. The investigation is based on an experimental two-cavity tool, where the cavities have different surface topographies, but are otherwise identical. The study has been carried out for typical commercial polystyrene and polypropylene grades. The relationship between mold surface topography and linear shrinkage has been investigated with an experimental two-cavity mold producing simple rectangular parts with the nominal dimensions 1 x 25 x 50 mm (see figure 1). The cavities have different surface topographies on one side, but are otherwise identical (see discussion of other contribution factors).

ArlØ, Uffe Rolf; Hansen, Hans NØrgaard

2003-01-01

133

Experimental validation of viscous and viscoelastic simulations of micro injection molding process  

DEFF Research Database (Denmark)

The effects of two different rheological models used in the simulation of the micro injection molding (µIM) process are investigated. The Cross-WLF viscous model and the Giesekus viscoelastic model are selected and their performance evaluated using 3D models implemented on two different commercially available software packages. Simulation results are then compared with the experimental µIM process. Validation parameters for the comparison are the flow front position during filling of the micro cavity. They are respectively obtained by applying the short-shots method and the flow-markers method. The µIM part is a polystyrene tensile bar test weighting 20mg and with three µ-features 300µm wide.

Gava, Alberto; Tosello, Guido

2009-01-01

134

Fabrication and characterization of injection molded multi level nano and microfluidic systems  

DEFF Research Database (Denmark)

We here present a method for fabrication of multi-level all-polymer chips by means of silicon dry etching, electroplating and injection molding. This method was used for successful fabrication of microfluidic chips for applications in the fields of electrochemistry, cell trapping and DNA elongation. These chips incorporate channel depths in the range between 100nm and 100?m and depth to width aspect ratios between 1/200 and 2. Optimization of the sealing process of all-polymer COC microfluidic chips by means of thermal bonding is also presented. The latter includes comparing the bonding strength of UV-treated foils and presentation of a simple model for estimating the delamination pressure. With UV surface treatments, foils of 100?m thickness were found to withstand pressures up to 9atm in Ø4mm cylindrical inlets when thermally bonded to micropatterned substrates of 2mm thickness.

Matteucci, Marco; Christiansen, Thomas Lehrmann

2013-01-01

135

Microstructure and mechanical behavior of metal injection molded Ti-Nb binary alloys as biomedical material.  

UK PubMed Central (United Kingdom)

The application of titanium (Ti) based biomedical materials which are widely used at present, such as commercially pure titanium (CP-Ti) and Ti-6Al-4V, are limited by the mismatch of Young's modulus between the implant and the bones, the high costs of products, and the difficulty of producing complex shapes of materials by conventional methods. Niobium (Nb) is a non-toxic element with strong ? stabilizing effect in Ti alloys, which makes Ti-Nb based alloys attractive for implant application. Metal injection molding (MIM) is a cost-efficient near-net shape process. Thus, it attracts growing interest for the processing of Ti and Ti alloys as biomaterial. In this investigation, metal injection molding was applied to the fabrication of a series of Ti-Nb binary alloys with niobium content ranging from 10wt% to 22wt%, and CP-Ti for comparison. Specimens were characterized by melt extraction, optical microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and transmission electron microscopy (TEM). Titanium carbide formation was observed in all the as-sintered Ti-Nb binary alloys but not in the as-sintered CP-Ti. Selected area electron diffraction (SAED) patterns revealed that the carbides are Ti2C. It was found that with increasing niobium content from 0% to 22%, the porosity increased from about 1.6% to 5.8%, and the carbide area fraction increased from 0% to about 1.8% in the as-sintered samples. The effects of niobium content, porosity and titanium carbides on mechanical properties have been discussed. The as-sintered Ti-Nb specimens exhibited an excellent combination of high tensile strength and low Young's modulus, but relatively low ductility.

Zhao D; Chang K; Ebel T; Qian M; Willumeit R; Yan M; Pyczak F

2013-08-01

136

CONVERSION OF WIND POWER TO HYDROGEN FUEL: DESIGN OF AN ALTERNATIVE ENERGY SYSTEM FOR AN INJECTION MOLDING FACILITY  

Science.gov (United States)

Injection molding plants are large consumers of electricity. At its current level of operations, Harbec Plastics (Ontario, NY) uses about 2,000,000 kilowatt-hours of electricity per year. Based on the US average fuel mix, approximately 1.5 pounds of CO2...

137

Thermal Properties of Extruded Injection-Molded Polycaprolactone/Gluten Bioblends Characterized by TGA, DSC, SEM and Infrared Photoacoustic Spectroscopy  

Science.gov (United States)

In order to determine the degree of compatibility between Polycaprolactone resin (PCL) and vital wheat gluten (VG), PCL was compounded with VG at 90:10, 80:20, 70:30, 60:40, 50:50, and 30:70. The composites were blended by extrusion followed by injection molding. Thermal, morphological, and struct...

138

Development and application of FINEMOLD. ; Powder metallurgy precision parts by injection molding. FINEMOLD no tenkai to oyo. ; Shashutsu seikei funmatsu yakin seimitsu buhin  

Energy Technology Data Exchange (ETDEWEB)

FINEMOLD is a trade name, given to powder metallurgy precision parts, produced by Nippon Seisen from metallic micropowder by an injection molding method. That company technically introduced the process from the USA in 1985 and entered the field of powder metallurgy by the injection molding. The production process of FINEMOLD proceeds in order of metallic powder kneading with binder, pelletizing, composing, injection molding, debinding, sintering and post-machining. The present production is, to the utmost, premised to be free from post-machining. However. parts unavoidably needing post-machining are to undergo sizing. That productio is maximally characterized by molding, entirely identical in method with that of plastics by use of injection molding machine. To specify the mold design, it is required to give instructions, specific to the injection molding, while the metallic micropowder is pricewise very expensive. Those points of problem must be engineered to be mitigated. 5 figs., 2 tabs.

Hattori, M. (Nihon Seisen Co. Ltd., Osaka (Japan))

1991-06-05

139

Mechanical properties of the weld line defect in micro injection molding for various nano filled polypropylene composites  

Energy Technology Data Exchange (ETDEWEB)

Research highlights: > PP/CNFs and PP/TiO{sub 2} composites with relative high loading fractions (10, 20, 30 and 35 wt%) were fabricated by inner melt mixing process. Micro tensile test samples were formed by injection molding combined with variotherm process for all composites. > The morphological properties of all nano composites were characterized by WXRD, whose results imply the adding nano fillers did not change the crystal form of PP, but the crystallites size and distance between lattices of crystals were changed with various nano fillers and loading fractions. > DSC analysis show that due to the nucleating function of nano fillers, the peak temperature of crystallization was increased and the peak temperature of crystallization melting was decreased by adding the nanofillers. > The flow ability of nano composites was tested by high pressure single capillary rheometer and the results demonstrate that nano fillers increased the viscosity of PP matrix. > Based on these significant information and analysis foundation of the nano filled composites, the micro weld line samples were formed by injection molding process and characterized by tensile test method. From the achieved results, it can be found that in general, for functional nano filled polymer composites, the mechanical property of micro weld lines were obviously influenced by nano fillers' shape and loading fractions. > The E modulus of micro weld line was increased due to loading CNFs in PP matrix, while the elongation of the micro tensile samples with weld line is considerably decreased comparing with those of unfilled PP samples. The detrimental tensile strength of micro weld lines were observed when CNFs contents increasing, except for at a 10 wt%. > For TiO{sub 2} nano particles filled PP, due to the poor dispersion of nano particles, at low loading fraction of 10 wt%, the E modulus and tensile strength of micro weld lines were decreased by filling nano particles, but when the loading fraction is increased to 30%, the E modulus and tensile strength of micro weld line were increased again compared with the low loading level. > Finally, an empirical prediction equation for micro injection molded weld line strength of nano PP composites was proposed for higher nano filler loading fraction than 10 wt%. - Abstract: The nano filled functional polymer materials have been widely processed with micro injection molding technology for micro electromechanical systems (MEMS) fabrication. As the unfavorable defect in micro injection molding parts, weld line brings reduced mechanical and physical properties, especially for nano filled composites. In this study, polypropylene (PP) was compounded respectively with carbon nano fibers (CNFs) and TiO{sub 2} nano particles at various weight fractions (10, 20, 30, 35 wt%) through co-screws internal mixing. The morphological, thermal and rheological properties of nano composites were characterized by wider angle X-ray diffraction (WXRD), different scanning calorimeter (DSC) and high pressure capillary rheometer. Additionally, under the constant setting of injection molding process parameters in injection molding machine, micro tensile samples with weld lines for each nano filled PP composite were produced. The tensile tests were served as the characterizing method for weld line mechanical properties. The results show that when the CNFs is filled higher than 10 wt%, the tensile strength of samples with weld lines made of nano composites become lower than neat PP. While the raising CNFs content contributes to the improved E modulus of micro injection molded weld lines. Additionally, with the increasing fraction of CNFs in PP, the weld line area's elongation percent is decreased. Whereas for case of TiO{sub 2}, the 10 wt% is the threshold for micro injection molded weld line tensile strength turning from decrease trend to increase. The same as CNFs, elongation of micro weld line samples were in general lower than neat PP as well, due to the addition of TiO{sub 2} nano particles.

Xie Lei, E-mail: Lei.Xie@tu-clausthal.de [Institute of Polymer Materials and Plastics Engineering, Technology University of Clausthal, Agricola str.6, 38678, Clausthal-Zellerfeld (Germany); Ziegmann, Gerhard [Institute of Polymer Materials and Plastics Engineering, Technology University of Clausthal, Agricola str.6, 38678, Clausthal-Zellerfeld (Germany)

2011-01-12

140

Conformal cooling and rapid thermal cycling in injection molding with 3D printed tools  

Science.gov (United States)

Solid Freeform Fabrication processes such as 3D Printing have demonstrated the potential to produce tools with complex internal geometry. This work explores the application of this capability to improved thermal management for injection molding tooling through: (i)cooling lines which are conformal to the mold surface which provide improved uniformity and stability of mold temperature and (ii)tools with low thermal inertia which, in combination with conformal fluid channels allow for rapid heating and cooling of tooling, thereby facilitating isothermal filling of the mold cavity. This work presents a systematic, modular, approach to the design of conformal cooling channels. Recognizing that the cooling is local to the surface of the tool, the tool is divided up into geometric regions and a channel system is designed for each region. Each channel system is itself modeled as composed of cooling elements, typically the region spanned by two channels. Six criteria are applied including; a transient heat transfer condition which dictates a maximum distance from mold surface to cooling channel, considerations of pressure and temperature drop along the flow channel and considerations of strength of the mold. These criteria are treated as constraints and successful designs are sought which define windows bounded by these constraints. The methodology is demonstrated in application to a complex core and cavity for injection molding. In the area of rapid thermal cycling, this work utilizes the design methods for conformal channels for the heating phases and adds analysis of the packing and cooling phases. A design is created which provides thermal isolation and accommodation of cyclic thermal stresses though an array of bendable support columns which support the molding portion of the tool where the heating/cooling channels are contained. Designed elasticity of the tool is used to aid in packing of the polymer during the cooling phase. Methodology for the design of this structure is presented. A set of tools has been fabricated and subjected to thermal and mechanical tests. (Copies available exclusively from MIT Libraries, Rm. 14- 0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

Xu, Xiaorong

 
 
 
 
141

An Approach to Rib Design of Injection Molded Product Using Finite Element and Taguchi Method  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study, not only Taguchi Method but also ANSYS in providing an economical and effective advance to the optimum design of the rib for a plastic injected product are introduced. The analytical model of a rectangular thermoplastic Acrylonitrile Butadiene Styrene (ABS) plastic cover with rib of g...

Tian-Syung Lan; Min-Chie Chiu; Long-Jyi Yeh

142

Thermal and mechanical behavior of injection molded Poly(3-hydroxybutyrate)/Poly(epsilon-caprolactone) blends  

Directory of Open Access Journals (Sweden)

Full Text Available Aiming the development of high-performance biodegradable polymer materials, the properties and the processing behavior of poly(3-hydroxybutyrate), P(3HB), and their blends with poly(epsilon-caprolactone), PCL, have been investigated. The P(3HB) sample, obtained from sugarcane, had a molecular weight of 3.0 x 10(5) g.mol¹, a crystallinity degree of 60%, a glass transition temperature (Tg), at - 0.8 °C, and a melting temperature at 171 °C. The molecular weight of PCL was 0.8 x 10(5) g.mol-1. Specimens of 70/30 wt. (%) P(3HB)/PCL blends obtained by injection molding showed tensile strength of 21.9 (± 0.4) MPa, modulus of 2.2 (± 0.3) GPa, and a relatively high elongation at break, 87 (± 20)%. DSC analyses of this blend showed two Tg´s, at - 10.6 °C for the P(3HB) matrix, and at - 62.9 °C for the PCL domains. The significant decrease on the Tg of P(3HB) evidences a partial miscibility of PCL in P(3HB). According to the Fox equation, the new Tg corresponds to a 92/8 wt. (%) P(3HB)/PCL composition.

Marcia Adriana Tomaz Duarte; Roberson Goulart Hugen; Eduardo Sant'Anna Martins; Ana Paula Testa Pezzin; Sérgio Henrique Pezzin

2006-01-01

143

Thermal and mechanical behavior of injection molded Poly(3-hydroxybutyrate)/Poly(epsilon-caprolactone) blends  

Directory of Open Access Journals (Sweden)

Full Text Available Aiming the development of high-performance biodegradable polymer materials, the properties and the processing behavior of poly(3-hydroxybutyrate), P(3HB), and their blends with poly(epsilon-caprolactone), PCL, have been investigated. The P(3HB) sample, obtained from sugarcane, had a molecular weight of 3.0 x 10(5) g.mol¹, a crystallinity degree of 60%, a glass transition temperature (Tg), at - 0.8 degreesC, and a melting temperature at 171 degreesC. The molecular weight of PCL was 0.8 x 10(5) g.mol-1. Specimens of 70/30 wt. (%) P(3HB)/PCL blends obtained by injection molding showed tensile strength of 21.9 (? 0.4) MPa, modulus of 2.2 (? 0.3) GPa, and a relatively high elongation at break, 87 (? 20)%. DSC analyses of this blend showed two Tgs, at - 10.6 degreesC for the P(3HB) matrix, and at - 62.9 degreesC for the PCL domains. The significant decrease on the Tg of P(3HB) evidences a partial miscibility of PCL in P(3HB). According to the Fox equation, the new Tg corresponds to a 92/8 wt. (%) P(3HB)/PCL composition.

Duarte Marcia Adriana Tomaz; Hugen Roberson Goulart; Martins Eduardo Sant'Anna; Pezzin Ana Paula Testa; Pezzin Sérgio Henrique

2006-01-01

144

Thermal and mechanical behavior of injection molded Poly(3-hydroxybutyrate)/Poly(epsilon-caprolactone) blends  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Aiming the development of high-performance biodegradable polymer materials, the properties and the processing behavior of poly(3-hydroxybutyrate), P(3HB), and their blends with poly(epsilon-caprolactone), PCL, have been investigated. The P(3HB) sample, obtained from sugarcane, had a molecular weight of 3.0 x 10(5) g.mol¹, a crystallinity degree of 60%, a glass transition temperature (Tg), at - 0.8 °C, and a melting temperature at 171 °C. The molecular weight of P (more) CL was 0.8 x 10(5) g.mol-1. Specimens of 70/30 wt. (%) P(3HB)/PCL blends obtained by injection molding showed tensile strength of 21.9 (± 0.4) MPa, modulus of 2.2 (± 0.3) GPa, and a relatively high elongation at break, 87 (± 20)%. DSC analyses of this blend showed two Tg´s, at - 10.6 °C for the P(3HB) matrix, and at - 62.9 °C for the PCL domains. The significant decrease on the Tg of P(3HB) evidences a partial miscibility of PCL in P(3HB). According to the Fox equation, the new Tg corresponds to a 92/8 wt. (%) P(3HB)/PCL composition.

Duarte, Marcia Adriana Tomaz; Hugen, Roberson Goulart; Martins, Eduardo Sant'Anna; Pezzin, Ana Paula Testa; Pezzin, Sérgio Henrique

2006-03-01

145

Trial production of titanium orthodontic brackets fabricated by metal injection molding (MIM) with sintering.  

UK PubMed Central (United Kingdom)

Safety and esthetics are two indispensable factors to consider when fabricating orthodontic brackets. However, these factors are not easily achieved when conventional techniques (including forging and casting) are used in the mass production of titanium brackets, albeit the brackets exhibit excellent biocompatibility. In the present study, orthodontic brackets were manufactured by metal powder injection molding with sintering. Brackets with three different base designs were made and subjected to compression shear tests for evaluation of their bonding strength to enamel substrate. The shapes given to the dimple of the base were spherical, oval, and grooved. The maximum shear forces for each type were 11.1 kgf, 7.6 kgf, and 18.5 kgf, respectively. The bonding strengths of the titanium bracket were equivalent to those obtained with conventional stainless steel brackets. Moreover, uniform distribution of Vickers hardness values (average, 240 +/- 40 Hv) measured at three locations indicated that the titanium bracket was uniformly sintered. Accordingly, titanium brackets thus fabricated exhibit a potential for clinical application.

Deguchi T; Ito M; Obata A; Koh Y; Yamagishi T; Oshida Y

1996-07-01

146

Surface Hardening of Powder Injection Molded 316L Stainless Steels Through Low-Temperature Carburization  

Science.gov (United States)

The surface hardness of powder injection molded (PIM) 316L is generally low due to the inherited austenitic structure and large grains induced during high-temperature sintering. To increase the surface hardness and the wear resistance, low-temperature carburization (LTC) was applied to PIM 316L. With carburization at 773 K (500 °C) for 24 hours, the resulting hardness at the surface increases from 160 to 810 HV due to the "colossal" supersaturation of interstitial carbon and M5C2 carbide, and the corrosion resistance is not deteriorated. The carburized depth is about 40 ?m, and the carbon content in this layer is about 3.25 wt pct or 13.5 at. pct, which causes lattice expansion of the austenite. When the carburization temperature increases to 823 K (550 °C), or the carburization time increases to 72 hours, chromium carbides are observed and the corrosion resistance is impaired. One distinct advantage of applying LTC to PIM 316L is that no acid cleaning process is required, unlike for wrought counterparts, because of the clean surface of the sintered materials.

Cheng, Li-Hui; Hwang, Kuen-Shyang

2013-02-01

147

Model and simulation for melt flow in micro-injection molding based on the PTT model  

Science.gov (United States)

Unsteady viscoelastic flows were studied using the finite element method in this work. The Phan-Thien-Tanner (PTT) model was used to represent the rheological behavior of viscoelastic fluids. To effectively describe the microscale effects, the slip boundary condition and surface tension were added to the mathematical model for melt flow in micro-injection molding. The new variational equation of pressure, including the viscoelastic parameters and slip boundary condition, was generalized using integration by parts. A computer code based on the finite element method and finite difference method was developed to solve the melt flow problem. Numerical simulation revealed that the melt viscoelasticity plays an important role in the prediction of melt pressure, temperature at the gate and the succeeding melt front advancement in the cavity. Using the viscoelastic model one can also control the rapid increase in simulated pressure, temperature, and reduce the filling difference among different cavities. The short shot experiments of micro-motor shaft showed that the predicted melt front from the viscoelastic model is in fair agreement with the corresponding experimental results.

Cao, Wei; Kong, Lingchao; Li, Qian; Ying, Jin; Shen, Changyu

2011-12-01

148

Development of a Plastic Injection Molding Processing Laboratory for Freshman Mechanical Engineering Technology Students  

Science.gov (United States)

As is the case with many educational institutions that offer a MET degree, an introductory course in manufacturing materials and processes is required. At Penn State Erie, The Behrend College, we offer first-year Mechanical Engineering Technology (MET) students the introductory manufacturing materials and processes course. The course has both a lecture and laboratory segment. During the lab segment of the course, students have the opportunity to experience: material testing, plant tours, manufacturing processes, statistical process control, and inspection/measurement techniques. With 10 PIM machines, 3 extrusion lines, 2 thermoforming machines, and 2 blow molding machines, Penn State Behrend has the largest educational plastic injection molding (PIM) laboratory in the country. Collaborative efforts were initiated between the Mechanical Engineering Technology and Plastics Engineering Technology departments to enhance the learning experience. Resulting from the collaboration a decision was made to add a PIM laboratory to emphasize the lecture on plastic materials and processes. The PIM laboratory was developed to give the student an introduction to the PIM process, machine, mold and the effects of processing variables on the parts. Also, students would gain knowledge regarding the effects of part design on the process. Prior to the implementation of this lab, the students went on plant tours or were shown videos of the PIM process.

Meckley, Jonathan A.; Nitterright, Fredrick A.

2009-07-27

149

Minimum Amount of Binder Removal Required during Solvent Debinding of Powder-Injection-Molded Compacts  

Science.gov (United States)

Unsatisfactory dimensional control, distortion, and defects are frequently observed in powder-injection-molded parts, particularly after the solvent and thermal-debinding processing steps. One of the reasons is that the amount of soluble binder removed during the first step, solvent debinding, is not great enough to form interconnected pores throughout the compact, particularly in the core region. Thus, blistering, cracking, and bubbles can form easily during the subsequent thermal debinding. To determine the minimum debinding fraction required for solvent debinding, at which point interconnected pore channels are formed at the center, modeling of the distribution of the remaining soluble binder in the compact was established. The actual distribution, which was obtained by measuring the binder content layer by layer with the soxhelt extraction method, is in good agreement with the model. The modeling, bubble test, and fluorescence dye-penetration analysis show that, regardless of the compact thickness, the minimum bulk debinding fraction needed is consistently approximately 59 pct, yielding a local debinding fraction of 37 pct and a porosity of 8.5 pct at the center. This porosity is close to the value at which pores in a sintered compact transform from open to closed at the beginning of the final stage of sintering.

Fan, Yang-Liang; Hwang, Kuen-Shyang; Wu, Shiau-Han; Liau, Yau-Ching

2009-04-01

150

Experimental Study of Fiber Length and Orientation in Injection Molded Natural Fiber/Starch Acetate Composites  

DEFF Research Database (Denmark)

Composite compounds based on triethyl citrate plasticized starch acetate and hemp and flax fibers were prepared by melt processing. Plasticizer contents from 20 to 35 wt% and fiber contents of 10 and 40 wt% were used. The compounded composites were injection molded to tensile test specimens. The effect of processing, melt viscosity and fiber type on the fiber length was investigated. The lengths of fully processed fibers were determined by dissolving the matrix and measuring the length of the remaining fibers by microscope analysis. A clear reductive effect of the processing on the fiber length was noticed. A reduction of fiber length along the increasing fiber content and the decreasing plasticizer content was also detected. This reduction originated from the increasing shear forces during compounding, which again depended on the increased viscosity of the material. Hemp fibers were shown to remain longer and fibrillate more than flax fibers, leading to higher aspect ratio. Thus, the reinforcement efficiencyof hemp fibers by the processing was improved, in contrast with flax fibers. In addition, the analysis of fiber dispersion and orientation showed a good dispersion of fibers in the matrix, and a predominant orientation of the fibers in the melt flow direction.

Peltola, Heidi; Madsen, Bo

2011-01-01

151

Automatic polishing process of plastic injection molds on a 5-axis milling center  

CERN Multimedia

The plastic injection mold manufacturing process includes polishing operations when surface roughness is critical or mirror effect is required to produce transparent parts. This polishing operation is mainly carried out manually by skilled workers of subcontractor companies. In this paper, we propose an automatic polishing technique on a 5-axis milling center in order to use the same means of production from machining to polishing and reduce the costs. We develop special algorithms to compute 5-axis cutter locations on free-form cavities in order to imitate the skills of the workers. These are based on both filling curves and trochoidal curves. The polishing force is ensured by the compliance of the passive tool itself and set-up by calibration between displacement and force based on a force sensor. The compliance of the tool helps to avoid kinematical error effects on the part during 5-axis tool movements. The effectiveness of the method in terms of the surface roughness quality and the simplicity of impleme...

Pessoles, Xavier; 10.1016/j.jmatprotec.2008.08.034

2010-01-01

152

Injection-molded capsular device for oral pulsatile release: development of a novel mold.  

UK PubMed Central (United Kingdom)

The development of a purposely devised mold and a newly set up injection molding (IM) manufacturing process was undertaken to prepare swellable/erodible hydroxypropyl cellulose-based capsular containers. When orally administered, such devices would be intended to achieve pulsatile and/or colonic time-dependent delivery of drugs. An in-depth evaluation of thermal, rheological, and mechanical characteristics of melt formulations/molded items made of the selected polymer (Klucel® LF) with increasing amounts of plasticizer (polyethylene glycol 1500, 5%-15% by weight) was preliminarily carried out. On the basis of the results obtained, a new mold was designed that allowed, through an automatic manufacturing cycle of 5 s duration, matching cap and body items to be prepared. These were subsequently filled and coupled to give a closed device of constant 600 ?m thickness. As compared with previous IM systems having the same composition, such capsules showed improved closure mechanism, technological properties, especially in terms of reproducibility of the shell thickness, and release performance. Moreover, the ability of the capsular container to impart a constant lag phase before the liberation of the contents was demonstrated irrespective of the conveyed formulation.

Zema L; Loreti G; Macchi E; Foppoli A; Maroni A; Gazzaniga A

2013-02-01

153

Unique opportunities in powder injection molding of refractory and hard materials  

International Nuclear Information System (INIS)

Powder injection molding (PIM) is a relatively new manufacturing process for the creation of complicated net-shapes outside the range usually possible via powder metallurgy technologies. This new process is now in production at more than 550 sites around the world. Although a small industry, PIM will soon pass $1 billion dollars (USA) in annual sales. This presentation overviews the PIM process, some of the new developments and some of the successes that have occurred with both refractory metals and hard metals. Example applications are seen in medical and dental devices, industrial components, wristwatches, jet engines, firearms, automotive components, and even hand tools. To help establish the novel growth opportunities, PIM is compared to other fabrication routes to better understand the design features arising with this new approach, providing a compelling case for substantial opportunities in the refractory and hard materials. Illustrations are provided of several components in production. New opportunities abound for the technology, since it eliminates the shape complexity barrier associated with die compaction and the cost of machining associated with complicated or dimensionally precise components. Further, a relative cost advantage exists for refractory and hard materials because PIM can use the same powders at the same prices as employed in alternative processes. Future successes will occur by early identification of candidate materials and designs. Early examples include tungsten heavy alloy components now reaching production rates of six million per month. (author)

2001-01-01

154

Fabrication of microstructures with extreme structural heights by vacuum reaction injection molding and electroforming  

International Nuclear Information System (INIS)

Development work has resulted in a vacuum reaction injection molding (RIM) process which allows to fabricate plastic microstructures having minimum lateral dimensions in the micrometer range and structural heights of several hundred micrometers. The plastic structures generated by this method on an electrically conductive gate plate can be used directly as templates for the production of metallic microstructures through electroforming. The mold inserts for the molding tools used in the RIM process are fabricated by synchrotron radiation lithography and electroforming on an electrically conductive base plate. Particularly stable mold inserts made of one single material with extremely plane surfaces are obtained by electrodeposition of metal such that it stands by several millimeters over the resist structures generated by lithography. The mold insert produced in this way is separated from the base plate and the resist structures are subsequently removed. The molding tests were performed at a purpose developed vacuum RIM apparatus. Methacrylate base casting resins were used with an internal mold release agent added in order to reduce the adhesion of the produced part on the mold insert. By the example of fabrication of separation nozzle structures with minimum lateral dimensions of about 3 ?m and a maximum structural height of 310 ?m it has been demonstrated that molding can be performed at 100% yield and that service he mold inserts can be achieved which are adequate for mass production. (orig./HP).

1987-01-01

155

Improvements in sintered density and dimensional stability of powder injection-molded 316L compacts by adjusting the alloying compositions  

International Nuclear Information System (INIS)

[en] Powder injection molding is a process that provides advantages when making small parts with high density and complicated shapes. However, dimensional control of powder injection-molded stainless steel parts is difficult due to the presence of the liquid phase and the large amount of shrinkage that occurs during sintering. This study examines whether such a problem can be overcome through adjustments in the alloy composition and by making use of Thermo-Calc analysis. The results show that, with an increase in the molybdenum content up to the maximum limit according to existing specifications, a compact can be sintered to high densities without the presence of the liquid phase, while maintaining it in the dual-phase region of ? + ?. In addition, dimensional control is improved. A slower heating rate is also found to be beneficial. These results are explained through dilatometric analysis and phase diagrams that are calculated using the Thermo-Calc program

2006-01-01

156

Unique crystal morphology and tensile properties of injection-molded bar of LLDPE by adding HDPE with different molecular weights  

International Nuclear Information System (INIS)

In this research, a linear low density polyethylene (LLDPE) was first melt blended with a series of high density polyethylenes (HDPE) with different molecular weights at a fixed ratio of LLDPE/HDPE = 90/10 (w/w). The prepared HDPE/LLDPE blends were then injection-molded into specimen bars through a dynamic packing injection molding (DPIM) technique, in which an oscillating shear field was imposed on the melt by two pistons that move reversibly with the same frequency during the packing stage. The crystal morphology, orientation and tensile properties were characterized by scanning electron microscopy, two-dimensional wide-angle X-ray scattering and Instron, respectively. Compared with conventional injection molding, DPIM caused an obvious increase in tensile strength in the injection-molded bars. Interestingly, LLDPE blended with low molecular weight HDPE (LMW-PE) was found to possess much higher tensile strength than that blended with high molecular weight HDPE (HMW-PE). Shish-kebab morphology was observed for all blends obtained, regardless of the molecular weight of the HDPE. However, thicker but shorter lamellae were observed for the LLDPE/LMW-PE blend, corresponding to a higher melting temperature; while thinner but longer lamellae were seen for the LLDPE/HMW-PE blend, corresponding to a lower melting temperature. Furthermore, the phase miscibility between HDPE and LLDPE was found to increase with increasing HDPE molecular weight, which would affect the sensitivity of molecular chains for response to external shear. The changed miscibility, together with the changed entanglement density in different HDPE was responsible for the change in tensile strength and unique crystal morphology of LLDPE induced by adding HDPE.

2008-01-01

157

Unique crystal morphology and tensile properties of injection-molded bar of LLDPE by adding HDPE with different molecular weights  

Energy Technology Data Exchange (ETDEWEB)

In this research, a linear low density polyethylene (LLDPE) was first melt blended with a series of high density polyethylenes (HDPE) with different molecular weights at a fixed ratio of LLDPE/HDPE = 90/10 (w/w). The prepared HDPE/LLDPE blends were then injection-molded into specimen bars through a dynamic packing injection molding (DPIM) technique, in which an oscillating shear field was imposed on the melt by two pistons that move reversibly with the same frequency during the packing stage. The crystal morphology, orientation and tensile properties were characterized by scanning electron microscopy, two-dimensional wide-angle X-ray scattering and Instron, respectively. Compared with conventional injection molding, DPIM caused an obvious increase in tensile strength in the injection-molded bars. Interestingly, LLDPE blended with low molecular weight HDPE (LMW-PE) was found to possess much higher tensile strength than that blended with high molecular weight HDPE (HMW-PE). Shish-kebab morphology was observed for all blends obtained, regardless of the molecular weight of the HDPE. However, thicker but shorter lamellae were observed for the LLDPE/LMW-PE blend, corresponding to a higher melting temperature; while thinner but longer lamellae were seen for the LLDPE/HMW-PE blend, corresponding to a lower melting temperature. Furthermore, the phase miscibility between HDPE and LLDPE was found to increase with increasing HDPE molecular weight, which would affect the sensitivity of molecular chains for response to external shear. The changed miscibility, together with the changed entanglement density in different HDPE was responsible for the change in tensile strength and unique crystal morphology of LLDPE induced by adding HDPE.

Liang, S.; Yang, H.; Wang, K.; Zhang, Q.; Du, R. [Department of Polymer Science and Materials, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065 (China); Fu, Q. [Department of Polymer Science and Materials, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065 (China)], E-mail: qiangfu@scu.edu.cn

2008-01-15

158

Development of injection molding used kucha-ceramics. Kucha nendo wo mochiita shashutsu seikei gijutsu no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

Properties of Kucha-clay were studied as material for injection molding. After the mixtures of the clay and binders were heated at 423 K for 6 hours, those were crushed to prepare pellets for injection molding, and after injection molding and degreasing, the molded pellets were sintered in temperature range of 1,273-1,448 K for 1-2 hours. As a result, polyethylene (PE) offered excellent properties as binder, and the mixed binder composed of PE, ethylene vinylacetate copolymer (EVA), paraffin wax and zinc stearin allowed to keep the molded pellets in shape. Linear low-density PE (LLDPE) could also reduce a binder content by 15wt% as compared with other binders. The hardness of products increased with sintering temperature, in particular, sharply at 1,373 K or more, accompanying shrinkage at 1,373 K or less and expansion at 1,373 K or more. The bending strength was higher in LLDPE than LDPE showing the maximum value of 108 MPa at 1,373 K. 5 refs., 15 figs., 3 tabs.

Fukumoto, I.; Mekaru, S.; Koja, M. (University of The Ryukyus, Okinawa (Japan). Faculty of Engineering); Teruya, Z. (Industrial Research Institute of Okinawa Prefecture, Okinawa (Japan))

1993-09-01

159

Metal injection molding of Ti-Mo-Al mixed powder. Ti-Mo-Al kongofun no idashi seikei  

Energy Technology Data Exchange (ETDEWEB)

Metal injection molding of Ti-15Mo-3Al alloys was studied by use of the Ti-Mo-Al compound composed of Ti powder with an average diameter of 38 [mu]m, Mo powder of 1.24 [mu]m, TiAl alloy powder of 9.4 [mu]m and two types of wax-polymer binders. Since oxidation of the compound in the air was depressed by using TiAl alloy powder substituted for Al powder, kneading, molding and debinding of the compound were successfully conducted in the air. The relative density of the sintered compacts approached as high as 97% or more through debinding at 210[degree]C in the air and at 500-550[degree]C in vacuum, and sintering at 1296[degree]C in vacuum for 3 hours. A large amount of precipitated Ti oxide particles were observed in sintered microstructures of die pressed compacts, however, in the case of injection molded compacts, since residual C derived from the binder reduced Ti oxides, TiC particles were observed instead of Ti oxide ones. Such precipitated TiC probably enhanced densification of the injection molded sintered compacts depressing crystal grain growth in them. 2 refs., 7 figs.

Takekawa, J. (Ishinomaki Senshu University, Miyagi (Japan))

1994-03-13

160

Recycling plastic scrap: Injection molding. January 1973-August 1989 (Citations from the Rubber and Plastics Research Association data base). Report for January 1973-August 1989  

Energy Technology Data Exchange (ETDEWEB)

This bibliography contains citations concerning the recycling of scrap plastic produced in the injection-molding process. Plastic pellets made from scrap that are used in the injection-molding process are also discussed. Recycling equipment and automated recycling systems are described. Ways to utilize plastic scrap from used cars, packaging materials, and waste from polyurethane production are presented. (This updated bibliography contains 116 citations, 14 of which are new entries to the previous edition.)

1989-09-01

 
 
 
 
161

Recycling plastic scrap: injection molding. January 1973-August 1988 (Citations from the Rubber and Plastics Research Association data base). Report for January 1973-August 1988  

Energy Technology Data Exchange (ETDEWEB)

This bibliography contains citations concerning the recycling of scrap plastic produced in the injection-molding process. Plastic pellets made from scrap that are used in the injection-molding process are also discussed. Recycling equipment and automated recycling systems are described. Ways to utilize plastic scrap from used cars, packaging materials, and waste from polyurethane production are presented. (This updated bibliography contains 102 citations, 13 of which are new entries to the previous edition.)

1988-08-01

162

Fabrication and characterization of injection molded poly ({epsilon}-caprolactone) and poly ({epsilon}-caprolactone)/hydroxyapatite scaffolds for tissue engineering  

Energy Technology Data Exchange (ETDEWEB)

In this study, poly({epsilon}-caprolactone) (PCL)/sodium chloride (NaCl), PCL/poly(ethylene oxide) (PEO)/NaCl and PCL/PEO/NaCl/hydroxyapatite (HA) composites were injection molded and characterized. The water soluble and sacrificial polymer, PEO, and NaCl particulates in the composites were leached by deionized water to produce porous and interconnected microstructures. The effect of leaching time on porosity, and residual contents of NaCl and NaCl/HA, as well as the effect of HA addition on mechanical properties was investigated. In addition, the biocompatibility was observed via seeding human mesenchymal stem cells (hMSCs) on PCL and PCL/HA scaffolds. The results showed that the leaching time depends on the spatial distribution of sacrificial PEO phase and NaCl particulates. The addition of HA has significantly improved the elastic (E Prime ) and loss moduli (E Double-Prime ) of PCL/HA scaffolds. Human MSCs were observed to have attached and proliferated on both PCL and PCL/HA scaffolds. Taken together, the molded PCL and PCL/HA scaffolds could be good candidates as tissue engineering scaffolds. Additionally, injection molding would be a potential and high throughput technology to fabricate tissue scaffolds. - Highlights: Black-Right-Pointing-Pointer PCL/NaCl, PCL/PEO/NaCl and PCL/PEO/NaCl/HA composites were injection molded. Black-Right-Pointing-Pointer Leaching time depends on the distribution of PEO phase and NaCl particulates. Black-Right-Pointing-Pointer The elastic and loss moduli of PCL/HA scaffolds have significantly improved. Black-Right-Pointing-Pointer Human hMSCs have attached, survived and proliferated well on PCL and PCL/HA scaffolds. Black-Right-Pointing-Pointer Molded PCL and PCL/HA scaffolds could be good candidates for tissue engineering.

Cui Zhixiang [Zhengzhou University, Henan (China); Nelson, Brenton; Peng, YiYan [University of Wisconsin-Madison, Wisconsin (United States); Li Ke [South China University of Technology, Guangzhou (China); Pilla, Srikanth; Li Wanju [University of Wisconsin-Madison, Wisconsin (United States); Turng, Lih-Sheng, E-mail: turng@engr.wisc.edu [University of Wisconsin-Madison, Wisconsin (United States); South China University of Technology, Guangzhou (China); Huazhong University of Science of Technology, Wuhan (China); Shen Changyu, E-mail: shency@zzu.edu.cn [Zhengzhou University, Henan (China)

2012-08-01

163

Fabrication and characterization of injection molded poly (?-caprolactone) and poly (?-caprolactone)/hydroxyapatite scaffolds for tissue engineering  

International Nuclear Information System (INIS)

In this study, poly(?-caprolactone) (PCL)/sodium chloride (NaCl), PCL/poly(ethylene oxide) (PEO)/NaCl and PCL/PEO/NaCl/hydroxyapatite (HA) composites were injection molded and characterized. The water soluble and sacrificial polymer, PEO, and NaCl particulates in the composites were leached by deionized water to produce porous and interconnected microstructures. The effect of leaching time on porosity, and residual contents of NaCl and NaCl/HA, as well as the effect of HA addition on mechanical properties was investigated. In addition, the biocompatibility was observed via seeding human mesenchymal stem cells (hMSCs) on PCL and PCL/HA scaffolds. The results showed that the leaching time depends on the spatial distribution of sacrificial PEO phase and NaCl particulates. The addition of HA has significantly improved the elastic (E?) and loss moduli (E?) of PCL/HA scaffolds. Human MSCs were observed to have attached and proliferated on both PCL and PCL/HA scaffolds. Taken together, the molded PCL and PCL/HA scaffolds could be good candidates as tissue engineering scaffolds. Additionally, injection molding would be a potential and high throughput technology to fabricate tissue scaffolds. - Highlights: ?PCL/NaCl, PCL/PEO/NaCl and PCL/PEO/NaCl/HA composites were injection molded. ?Leaching time depends on the distribution of PEO phase and NaCl particulates. ?The elastic and loss moduli of PCL/HA scaffolds have significantly improved. ?Human hMSCs have attached, survived and proliferated well on PCL and PCL/HA scaffolds. ?Molded PCL and PCL/HA scaffolds could be good candidates for tissue engineering.

2012-08-01

164

Design and development of an injection-molded demultiplexer for optical communication systems in the visible range.  

UK PubMed Central (United Kingdom)

Optical simulation software based on the ray-tracing method offers easy and fast results in imaging optics. This method can also be applied in other fields of light propagation. For short distance communications, polymer optical fibers (POFs) are gradually gaining importance. This kind of fiber offers a larger core diameter, e.g., the step index POF features a core diameter of 980 ?m. Consequently, POFs have a large number of modes (>3 million modes) in the visible range, and ray tracing could be used to simulate the propagation of light. This simulation method is applicable not only for the fiber itself but also for the key components of a complete POF network, e.g., couplers or other key elements of the transmission line. In this paper a demultiplexer designed and developed by means of ray tracing is presented. Compared to the classical optical design, requirements for optimal design differ particularly with regard to minimizing the insertion loss (IL). The basis of the presented key element is a WDM device using a Rowland spectrometer setup. In this approach the input fiber carries multiple wavelengths, which will be divided into multiple output fibers that transmit only one wavelength. To adapt the basic setup to POF, the guidance of light in this element has to be changed fundamentally. Here, a monolithic approach is presented with a blazed grating using an aspheric mirror to minimize most of the aberrations. In the simulations the POF is represented by an area light source, while the grating is analyzed for different orders and the highest possible efficiency. In general, the element should be designed in a way that it can be produced with a mass production technology like injection molding in order to offer a reasonable price. However, designing the elements with regard to injection molding leads to some inherent challenges. The microstructure of an optical grating and the thick-walled 3D molded parts both result in high demands on the injection molding process. This also requires complex machining of the molding tool. Therefore, different experiments are done to optimize the process parameter, find the best molding material, and find a suitable machining method for the molding tool. The paper will describe the development of the demultiplexer by means of ray-tracing simulations step by step. Also, the process steps and the realized solutions for the injection molding are described.

Höll S; Haupt M; Fischer UH

2013-06-01

165

Design and development of an injection-molded demultiplexer for optical communication systems in the visible range.  

Science.gov (United States)

Optical simulation software based on the ray-tracing method offers easy and fast results in imaging optics. This method can also be applied in other fields of light propagation. For short distance communications, polymer optical fibers (POFs) are gradually gaining importance. This kind of fiber offers a larger core diameter, e.g., the step index POF features a core diameter of 980 ?m. Consequently, POFs have a large number of modes (>3 million modes) in the visible range, and ray tracing could be used to simulate the propagation of light. This simulation method is applicable not only for the fiber itself but also for the key components of a complete POF network, e.g., couplers or other key elements of the transmission line. In this paper a demultiplexer designed and developed by means of ray tracing is presented. Compared to the classical optical design, requirements for optimal design differ particularly with regard to minimizing the insertion loss (IL). The basis of the presented key element is a WDM device using a Rowland spectrometer setup. In this approach the input fiber carries multiple wavelengths, which will be divided into multiple output fibers that transmit only one wavelength. To adapt the basic setup to POF, the guidance of light in this element has to be changed fundamentally. Here, a monolithic approach is presented with a blazed grating using an aspheric mirror to minimize most of the aberrations. In the simulations the POF is represented by an area light source, while the grating is analyzed for different orders and the highest possible efficiency. In general, the element should be designed in a way that it can be produced with a mass production technology like injection molding in order to offer a reasonable price. However, designing the elements with regard to injection molding leads to some inherent challenges. The microstructure of an optical grating and the thick-walled 3D molded parts both result in high demands on the injection molding process. This also requires complex machining of the molding tool. Therefore, different experiments are done to optimize the process parameter, find the best molding material, and find a suitable machining method for the molding tool. The paper will describe the development of the demultiplexer by means of ray-tracing simulations step by step. Also, the process steps and the realized solutions for the injection molding are described. PMID:23842150

Höll, S; Haupt, M; Fischer, U H P

2013-06-20

166

Modeling and Analysis of Process Parameters for Evaluating Shrinkage Problems During Plastic Injection Molding of a DVD-ROM Cover  

Science.gov (United States)

Plastic injection molding plays a key role in the production of high-quality plastic parts. Shrinkage is one of the most significant problems of a plastic part in terms of quality in the plastic injection molding. This article focuses on the study of the modeling and analysis of the effects of process parameters on the shrinkage by evaluating the quality of the plastic part of a DVD-ROM cover made with Acrylonitrile Butadiene Styrene (ABS) polymer material. An effective regression model was developed to determine the mathematical relationship between the process parameters (mold temperature, melt temperature, injection pressure, injection time, and cooling time) and the volumetric shrinkage by utilizing the analysis data. Finite element (FE) analyses designed by Taguchi (L27) orthogonal arrays were run in the Moldflow simulation program. Analysis of variance (ANOVA) was then performed to check the adequacy of the regression model and to determine the effect of the process parameters on the shrinkage. Experiments were conducted to control the accuracy of the regression model with the FE analyses obtained from Moldflow. The results show that the regression model agrees very well with the FE analyses and the experiments. From this, it can be concluded that this study succeeded in modeling the shrinkage problem in our application.

Öktem, H.

2012-01-01

167

Low Speed Technology for Small Turbine Development Reaction Injection Molded 7.5 Meter Wind Turbine Blade  

Energy Technology Data Exchange (ETDEWEB)

An optimized small turbine blade (7.5m radius) was designed and a partial section molded with the RIM (reaction-injection molded polymer) process for mass production. The intended market is for generic three-bladed wind turbines, 100 kilowatts or less, for grid-assist end users with rural and semi-rural sites, such as the farm/ranch market, having low to moderate IEC Class 3-4 wind regimes. This blade will have substantial performance improvements over, and be cheaper than, present-day 7.5m blades. This is made possible by the injection-molding process, which yields high repeatability, accurate geometry and weights, and low cost in production quantities. No wind turbine blade in the 7.5m or greater size has used this process. The blade design chosen uses a RIM skin bonded to a braided infused carbon fiber/epoxy spar. This approach is attractive to present users of wind turbine blades in the 5-10m sizes. These include rebladeing California wind farms, refurbishing used turbines for the Midwest farm market, and other manufacturers introducing new turbines in this size range.

David M. Wright; DOE Project Officer - Keith Bennett

2007-07-31

168

Feature-based non-manifold modeling system to integrate design and analysis of injection molding products  

International Nuclear Information System (INIS)

Current CAE systems used for both the simulation of the injection molding process and the structural analysis of plastic parts accept solid models as geometric input. However, abstract models composed of sheets and wireframes are still used by CAE systems to carry out more analyses more efficiently. Therefore, to obtain an adequate abstract model, designers often have to simplify and idealize a detailed model of a part to a specific level of detail and/or abstraction. For such a process, we developed a feature-based design system based on a non-manifold modeling kernel supporting feature-based multi-resolution and multi-abstraction modeling capabilities. In this system, the geometric models for the CAD and CAE systems are merged into a single master model in a non-manifold topological representation, and then, for a given level of detail and abstraction, a simplified solid or non-manifold model is extracted immediately for an analysis. For a design change, the design and analysis models are modified simultaneously. As a result, this feature based design system is able to provide a more integrated environment for the design and analysis of plastic injection molding parts

2009-01-01

169

Experimental Analysis for Factors Affecting the Repeatability of Plastics Injection Molding Tests on the Self-developed Apparatus  

Directory of Open Access Journals (Sweden)

Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 To improve the repeatability of the injection molding test result, the affecting factors were investigated by means of experiments. Besides the traditional processing parameter, the factors of test conditions were also considered. In order to focus on the molding process rather than the molded part, the curve measurement of the melt pressure at the entrance to the nozzle was used as the output characteristic. Experiments for polypropylene (PP) showed that the injected volume was the key processing parameter. Within the test conditions, the injection number is the most important factor. According to the analysis the operating procedure was improved effectively. Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 Doi: 10.12777/ijse.5.1.6-11 [How to cite this article: Huang, Y., Li, D., Liu, Y. (2013). Experimental Analysis for Factors Affecting the Repeatability of Plastics Injection Molding Tests on the Self-developed Apparatus. International Journal of Science and Engineering, 5(1),6-11. Doi: 10.12777/ijse.5.1.6-11

Yugang Huang; Duxin Li; Yuejun Liu

2013-01-01

170

An Approach to Rib Design of Injection Molded Product Using Finite Element and Taguchi Method  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, not only Taguchi Method but also ANSYS in providing an economical and effective advance to the optimum design of the rib for a plastic injected product are introduced. The analytical model of a rectangular thermoplastic Acrylonitrile Butadiene Styrene (ABS) plastic cover with rib of given thickness (2.8 mm) was selected and constructed based on design experiences and the dimensions as well as the width of the rib were selected as the control factors for Taguchi Method. The deflection under a constant force of 150 Newton at the back centre of the cover was defined as quality characteristic. Additionally, the deformation experiment on a fixed thin beam was compared with the analytical result from ANSYS to verify the reliability of structure analysis from associated parameter setup and boundary condition operation. The L9(34) orthogonal array from Taguchi Method was moreover arranged to establish nine sets of finite element analysis models. Through Taguchi Method, the optimum design parameters were furthermore received from minimum deformation at back centre of the plastic cover analyzed by ANSYS. It is shown that the optimum structural parameters of a plastic rib can surely be effectively found with the integration of both Taguchi Method and ANSYS. Therefore, an Expert System of optimum design for various shapes of ribs can then be constructed through this study. This study exactly contributes a novel technique to the rib design for plastic injection industry in minimizing the development period of a new product.

Tian-Syung Lan; Min-Chie Chiu; Long-Jyi Yeh

2008-01-01

171

Development and industrialization of olefin-based thermoplastic elastomer  

Energy Technology Data Exchange (ETDEWEB)

Thermoplastic elastomer is polymeric material which is plasticized at high temperature, can be fabricated like the existing thermoplastic resins and shows rubber elasticity at room temterature. Olefin-based thermoplastic elastomer (TPO) came into market for the first time in 1972 in the U.S.A.. Mitsui Petrochemical Industries Ltd Co. introduced in 1955 the ziegler polyethylene production technology and industrialized various olefin-based resins and elastomers after succeeding the development of the process and the highly active catalyst. In 1973, the company started a research of TPO which consisted mainly of olefin-based resins and elastomers and commenced its production in a pilot plant in 1976. This article explains an outline and the features of the basic technology concerning this TPO. Its features are to show the intermediate nature between elastomer and resin, be very easy for injection molding, be good at electric insulation, heat-aging proof, chemical proof, weather proof and specific weight, but be insufficient at oil proof and scratch proof. (6 figs, 2 tabs, 6 refs)

Matsuda, Akira

1988-09-01

172

Biocompatibility of metal injection molded versus wrought ASTM F562 (MP35N) and ASTM F1537 (CCM) cobalt alloys.  

UK PubMed Central (United Kingdom)

We present a comparative analysis between biocompatibility test results of wrought and Metal Injection Molded (MIM) ASTM F562-02 UNS R30035 (MP35N) and F1537 UNS R31538 (CCM) alloy samples that have undergone the same generic orthopedic implant's mechanical, chemical surface pre-treatment, and a designed pre-testing sample preparation method. Because the biocompatibility properties resulting from this new MIM cobalt alloy process are not well understood, we conducted tests to evaluate cytotoxicity (in vitro), hemolysis (in vitro), toxicity effects (in vivo), tissue irritation level (in vivo), and pyrogenicity count (in vitro) on such samples. We show that our developed MIM MP35N and CCM materials and treatment processes are biocompatible, and that both the MIM and wrought samples, although somewhat different in microstructure and surface, do not show significant differences in biocompatibility.

Chen H; Sago A; West S; Farina J; Eckert J; Broadley M

2011-01-01

173

Biocompatibility of metal injection molded versus wrought ASTM F562 (MP35N) and ASTM F1537 (CCM) cobalt alloys.  

Science.gov (United States)

We present a comparative analysis between biocompatibility test results of wrought and Metal Injection Molded (MIM) ASTM F562-02 UNS R30035 (MP35N) and F1537 UNS R31538 (CCM) alloy samples that have undergone the same generic orthopedic implant's mechanical, chemical surface pre-treatment, and a designed pre-testing sample preparation method. Because the biocompatibility properties resulting from this new MIM cobalt alloy process are not well understood, we conducted tests to evaluate cytotoxicity (in vitro), hemolysis (in vitro), toxicity effects (in vivo), tissue irritation level (in vivo), and pyrogenicity count (in vitro) on such samples. We show that our developed MIM MP35N and CCM materials and treatment processes are biocompatible, and that both the MIM and wrought samples, although somewhat different in microstructure and surface, do not show significant differences in biocompatibility. PMID:21537059

Chen, Hao; Sago, Alan; West, Shari; Farina, Jeff; Eckert, John; Broadley, Mark

2011-01-01

174

Die-sinking electrical discharge machining of a high-strength copper-based alloy for injection molds  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english High-strength copper alloys are used as materials for injection molding tools or as cores and inserts in steel molds because of their high thermal conductivity, corrosion and wear resistance. Unfortunately, there is little technological knowledge on the electrical discharge machining (EDM) of copper-beryllium ASTM C17200 alloy. In this work, rough and finish machining conditions were tested using copper and tungsten-copper as materials for the electrodes. Cross-sectional (more) micrographic and hardness examinations as well as surface roughness measurements were also carried out on workpieces after machining in order to study the thermally affected zones. Appropriate parameters settings for EDM of the investigated alloy are suggested.

Amorim, F. L.; Weingaertner, W. L.

2004-06-01

175

DNA barcoding via counterstaining with AT/GC sensitive ligands in injection-molded all-polymer nanochannel devices  

DEFF Research Database (Denmark)

Nanochannel technology, coupled with a suitable DNA labeling chemistry, is a powerful approach for performing high-throughput single-molecule mapping of genomes. Yet so far nanochannel technology has remained inaccessible to the broader research community due to high fabrication cost and/or requirement of specialized facilities/skill-sets. In this article we show that nanochannel-based mapping can be performed in all polymer chips fabricated via injection molding: a fabrication process so inexpensive that the devices can be considered disposable. Fluorescent intensity variations can be obtained from molecules extended in the polymer nanochannels via chemical counterstaining against YOYO-1. In particular, we demonstrate that the counterstaining induced fluorescent intensity variations to a large degree appear to be proportional to the theoretically computed sequence-maps of both local AT and GC variation along DNA sequences.

Østergaard, Peter Friis; Matteucci, Marco

2012-01-01

176

Influence of different process settings conditions on the accuracy of micro injection molding simulations: an experimental validation  

DEFF Research Database (Denmark)

Currently available software packages exhibit poor results accuracy when performing micro injection molding (µIM) simulations. However, with an appropriate set-up of the processing conditions, the quality of results can be improved. The effects on the simulation results of different and alternative process conditions are investigated, namely the nominal injection speed, as well as the cavity filling time and the evolution of the cavity injection pressure as experimental data. In addition, the sensitivity of the results to the quality of the rheological data is analyzed. Simulated results are compared with experiments in terms of flow front position at part and micro features levels, as well as cavity injection filling time measurements.

Tosello, Guido; Gava, Alberto

2009-01-01

177

Die-sinking electrical discharge machining of a high-strength copper-based alloy for injection molds  

Directory of Open Access Journals (Sweden)

Full Text Available High-strength copper alloys are used as materials for injection molding tools or as cores and inserts in steel molds because of their high thermal conductivity, corrosion and wear resistance. Unfortunately, there is little technological knowledge on the electrical discharge machining (EDM) of copper-beryllium ASTM C17200 alloy. In this work, rough and finish machining conditions were tested using copper and tungsten-copper as materials for the electrodes. Cross-sectional micrographic and hardness examinations as well as surface roughness measurements were also carried out on workpieces after machining in order to study the thermally affected zones. Appropriate parameters settings for EDM of the investigated alloy are suggested.

F. L. Amorim; W. L. Weingaertner

2004-01-01

178

Molecular weight dependence of hybrid shish kebab structure in injection molded bar of polyethylene/inorganic whisker composites.  

UK PubMed Central (United Kingdom)

In our previous work, a hybrid shish kebab structure, with polyethylene (PE) crystal lamellae periodically decorated on the surface of an inorganic whisker (SMCW) and aligned approximately perpendicular to the long axis of the whisker, has been observed in the injection molded bar of PE/SMCW composites. To investigate the effect of the molecular weight of the PE matrix on the formation of the hybrid shish kebab structure and the corresponding physical properties of HDPE/SMCW composites, in this work, three types of PE with different molecular weights were used to prepare the composites. They were first melt blended and then subjected to dynamic packing injection molding (DPIM), in which the prolonged shear was exerted on the melt during the solidification stage. An obvious hybrid shish kebab (HSK) structure, with PE crystal lamellae closely packed on the surface of the SMCW, was found in the samples with a low molecular weight PE (LMW-PE) matrix and a medium molecular weight PE (MMW-PE) matrix. However, in samples with a high molecular weight PE (HMW-PE) matrix, an incomplete HSK structure with PE crystal lamellae loosely decorated on the surface of the SMCW was observed. Furthermore, DSC results indicated that SMCW served as a good nucleating agent only for the composite with a LMW-PE matrix and the nucleation efficiency decreased with increasing PE molecular weight. Correspondingly, the tensile strength of the PE/SMCW composites was significantly improved by adding SMCW for the samples with a LMW-PE or MMW-PE matrix. Especially for samples with a LMW-PE matrix, the tensile strength was remarkably enhanced by the presence of only 1 wt % SMCW. For the composites with a HMW-PE matrix, the addition of SMCW had almost no reinforcing effect on the composites. The molecular weight dependence of the formation of HSK and property enhancement was discussed on the basis of the chain mobility and crystallization capability of the PE matrix.

Ning N; Luo F; Wang K; Zhang Q; Chen F; Du R; An C; Pan B; Fu Q

2008-11-01

179

Molecular weight dependence of hybrid shish kebab structure in injection molded bar of polyethylene/inorganic whisker composites.  

Science.gov (United States)

In our previous work, a hybrid shish kebab structure, with polyethylene (PE) crystal lamellae periodically decorated on the surface of an inorganic whisker (SMCW) and aligned approximately perpendicular to the long axis of the whisker, has been observed in the injection molded bar of PE/SMCW composites. To investigate the effect of the molecular weight of the PE matrix on the formation of the hybrid shish kebab structure and the corresponding physical properties of HDPE/SMCW composites, in this work, three types of PE with different molecular weights were used to prepare the composites. They were first melt blended and then subjected to dynamic packing injection molding (DPIM), in which the prolonged shear was exerted on the melt during the solidification stage. An obvious hybrid shish kebab (HSK) structure, with PE crystal lamellae closely packed on the surface of the SMCW, was found in the samples with a low molecular weight PE (LMW-PE) matrix and a medium molecular weight PE (MMW-PE) matrix. However, in samples with a high molecular weight PE (HMW-PE) matrix, an incomplete HSK structure with PE crystal lamellae loosely decorated on the surface of the SMCW was observed. Furthermore, DSC results indicated that SMCW served as a good nucleating agent only for the composite with a LMW-PE matrix and the nucleation efficiency decreased with increasing PE molecular weight. Correspondingly, the tensile strength of the PE/SMCW composites was significantly improved by adding SMCW for the samples with a LMW-PE or MMW-PE matrix. Especially for samples with a LMW-PE matrix, the tensile strength was remarkably enhanced by the presence of only 1 wt % SMCW. For the composites with a HMW-PE matrix, the addition of SMCW had almost no reinforcing effect on the composites. The molecular weight dependence of the formation of HSK and property enhancement was discussed on the basis of the chain mobility and crystallization capability of the PE matrix. PMID:18925778

Ning, Nanying; Luo, Feng; Wang, Ke; Zhang, Qin; Chen, Feng; Du, Rongni; An, Chunyang; Pan, Baofeng; Fu, Qiang

2008-10-17

180

A X-ray study of ?-phase and molecular orientation in nucleated and non-nucleated injection molded polypropylene resins  

Directory of Open Access Journals (Sweden)

Full Text Available The development of ? and ?-phases and the molecular orientation of injection molded disks of two isotactic polypropylene (i-PP) resins were studied by wide angle X-ray diffraction (WAXD) and pole figures. A nucleated (NPP) and non-nucleated (HPP) polymers were analyzed. The main proposal of this article was the comprehensive study of the interrelations between the processing conditions, phase contents and PP ?-phase molecular orientation of injection molded PP resins. In both resins, it was observed that the ?-phase was present in all regions along the thickness while the ?-phase was present mainly in the external layers, decreasing from the surface to the core; however this last phase was present in a very small amount in the NPP resin. For both polymers, the orientation of the macromolecules c-axis was higher along the flow direction (RD) than along the transverse direction (TD). The b-axis of the PP ?-phase molecules was oriented to the thickness direction (ND). The orientation of the c-axis along RD and b-axis along ND of the NPP samples was considerably higher than of the HPP samples, due to the NPP faster crystallization kinetics. For both polymers, the most influential processing parameters on the molecular orientation were the mold temperature and flow rate. The results indicate that, as the mold temperature increased, the characteristic molecular orientation of PP ?-phase, with c-axis along RD and b-axis along ND, decreased. With increase in the flow rate an increase of the c-axis molecular orientation of the samples along RD was observed.

Marcia Maria Favaro; Marcia Cristina Branciforti; Rosario Elida Suman Bretas

2009-01-01

 
 
 
 
181

Injection Molding of Titanium Alloy Implant For Biomedical Application Using Novel Binder System Based on Palm Oil Derivatives  

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement: Titanium alloy (Ti6Al4V) has been widely used as an implant for biomedical application. In this study, the implant had been fabricated using high technology of Powder Injection Molding (PIM) process due to the cost effective technique for producing small, complex and precision parts in high volume compared with conventional method through machining. Approach: Through PIM, the binder system is one of the most important criteria in order to successfully fabricate the implants. Even though, the binder system is a temporary, but failure in the selection and removal of the binder system will affect on the final properties of the sintered parts. Therefore, the binder system based on palm oil derivative which is palm stearin had been formulated and developed to replace the conventional binder system. Results: The rheological studies of the mixture between the powder and binders system had been determined properly in order to be successful during injection into injection molding machine. After molding, the binder held the particles in place. The binder system had to be removed completely through debinding step. During debinding step, solvent debinding and thermal pyrolysis had been used to remove completely of the binder system. The debound part was then sintered to give the required physical and mechanical properties. The in vitro biocompatibility also was tested using Neutral Red (NR) and mouse fibroblast cell lines L-929 for the direct contact assay. Conclusion: The results showed that the properties of the final sintered parts fulfill the Standard Metal Powder Industries Federation (MPIF) 35 for PIM parts except for tensile strength and elongation due to the formation of titanium carbide. The in vitro biocompatibility on the extraction using mouse fibroblast cell line L-929 by means of NR assays showed non toxic for the sintered specimen titanium alloy parts.

R. Ibrahim; M. Azmirruddin; M. Jabir; M. R. Ismail; M. Muhamad; R. Awang; S. Muhamad

2010-01-01

182

Nonlinear rheology and strain recovery of short chain branched polyolefin elastomers and thermoplastic olefin blends  

Science.gov (United States)

Polyolefin elastomers are random copolymers having a polyethylene backbone with the higher olefinic comonomer incorporated as short-chain branches. These random copolymers are widely used as polymer modifiers for thermoplastic materials such as polypropylenes, resulting in thermoplastic olefin (TPO) blends. This thesis addresses the nonlinear rheological behavior of the elastomers and then of the TPO blends. The effects of varying short chain branch density (SCB) on the melt rheology of three ethylene-octene random copolymers have been investigated. In particular, the strain-hardening behavior in extensional flow and strain recovery following nonlinear shear creep has been evaluated. The zero-shear viscosity followed trends in the backbone molecular weight closely. While the three copolymers were indistinguishable in linear viscoelastic creep and recovery, recovery following nonlinear shear creep decreased progressively with increasing SCB density. This reveals that the extent of rapid chain equilibration that occurs over Rouse time scales at higher strains was progressively lower with increasing SCB density. Strain hardening in uniaxial extensional flow was observed for all three copolymers. At strain rates below the primitive chain equilibration rates, strain hardening increases progressively with increasing SCB density. At higher rates, upon onset of primitive chain stretch, the strain hardening behavior for the three melts merges. Two thermoplastic olefin (TPO) blends were characterized in the context of injection molding; the surface morphology of injection molded tensile bars with these materials showed surface defects or flow marks to different extents. The flow marks were traced to different degrees of strain recovery in the dispersed phases of the two blends. This recovery occurred over injection molding timescales of the order of a few seconds. Strain recovery after shear creep was higher in the blend that displayed more severe flow marks in injection molding; the corresponding elastomer by itself also showed a greater extent of creep recovery. The quick strain recovery in the elastomer must be associated with elastic stresses rather than interfacial tension. A new experimental apparatus was assembled to study strain recovery after elongation of a model elastomer suspended in a less viscoelastic medium at room temperature. Small drops of well-characterized elastomers suspended in a matrix fluid of lower viscosity and elasticity, are stretched rapidly without wall effects in this setup; the stretch ratio of the drops is then recorded over time. Preliminary results confirm significant recovery over a few seconds. Exploration of the full range of parameters with this setup is left for future work.

Patham, Bhaskar

183

EXTRUDED AND INJECTION MOLDED BIOPOLYMERS: PROPERTIES OF POLYLACTIC ACID PLA/SUGAR-BEET PULP BLENDS, AND WHEY PROTEIN/CORN GLUTEN MEAL (CGM)  

Science.gov (United States)

In this study, processing techniques for extruded foods and non-foods using new and novel ingredients, to create unique bio-polymer blends, are emphasized. Our team in the Center of Excellence for Extrusion and Polymer Rheology (CEEPR) has recently used extrusion processing and injection molding (I...

184

Effect of mixing on the rheology and particle characteristics of tungsten-based powder injection molding feedstock  

International Nuclear Information System (INIS)

[en] This study investigates the effect of mixing technique and particle characteristics on the rheology and agglomerate dispersion of tungsten-based powder injection molding (PIM) feedstock. Experiments were conducted with as-received (agglomerated) and rod-milled (deagglomerated) tungsten powder mixed in a paraffin wax-polypropylene binder. Increase in the mixing shear rate decreased the agglomerate size of the agglomerated tungsten powder, decreased the viscosity, and improved the flow stability of the feedstock, interpreted as increased homogeneity of the feedstock. Higher solids volume fraction, lower mixing torques, and improved homogeneity were observed with deagglomerated tungsten powder, emphasizing the importance of particle characteristics and mixing procedures in the PIM process. Hydrodynamic stress due to mixing and the cohesive strength of the tungsten agglomerate were calculated to understand the mechanism of deagglomeration and quantify the effect of mixing. It was concluded that deagglomeration occurs due to a combination of rupture and erosion with the local hydrodynamic stresses exceeding the cohesive strength of the agglomerate

2003-09-15

185

Improvement of the Dimensional Stability of Powder Injection Molded Compacts by Adding Swelling Inhibitor into the Debinding Solvent  

Science.gov (United States)

Defects are frequently found in powder injection molded (PIM) compacts during solvent debinding due to the swelling of the binders. This problem can be alleviated by adjusting the composition of the debinding solvent. In this study, 10 vol pct swelling inhibitors were added into heptane, and the in-situ amounts of swelling and sagging of the specimen in the solvent were recorded using a noncontacting laser dilatometer. The results show that the addition of ethanol, 2-propanol, 1-butanol, and 1-pentanol reduced the amounts of swelling by 31, 21, 17, and 11 pct, respectively. This was because the small molecule alcohols, which do not dissolve paraffin wax (PW) or stearic acid (SA) in the binder system, could diffuse easily into the specimen and increased the portion of the swelling inhibitor inside. The amount of the extracted PW and SA also decreased, but only by 8.3, 6.1, 4.3, and 2.4 pct, respectively. The solubility parameters of 1-bromopropane (n-PB) and ethyl acetate (EA) are between those of heptane and alcohols, and they also yielded a slight reduction in the amounts of swelling by 6 and 11 pct, respectively. These results suggest that to reduce defects caused by binder swelling during solvent debinding, alcohols with high solubility parameters can be added into heptane without sacrificing significantly on the debinding rate.

Fan, Yang-Liang; Hwang, Kuen-Shyang; Su, Shao-Chin

2008-02-01

186

Single Performance Optimization of Micro Metal Injection Molding for the Highest Green Strength by Using Taguchi Method  

Directory of Open Access Journals (Sweden)

Full Text Available Micro metal injection molding is drawing attention recently as one the most cost effective processes in powder metallurgy to produce small-scale intricate part and competitive cost for mass production of micro components where it is greatly influenced by injection parameter. Thus, this paper investigated the optimization of highest green strength which plays an important characteristic in determining the successful of micro MIM. Stainless steel SS 316L was used with composite binder, which consists of PEG and PMMA while SA works as a surfactant. Feedstock with 61.5% with several injection parameters were optimized which highly significant through screening experiment such as injection pressure(A), injection temperature(B), mold temperature(C), injection time(D) and holding time(E). Besides that, interaction effects between injection pressure, injection temperature and mold temperature were also considered to optimize in the Taguchi’s orthogonal array. Analysis of variance (ANOVA) in terms of signal-to-noise ratio (S/N-larger is better) for green strength was also presented in this paper. Result shows that interaction between injection temperature and mold temperature (BxC) give highest significant factor followed by interaction between injection pressure and injection temperature (AxB). Single factor that also contributes to significant optimization are mold temperature(C), injection time (D) and injection pressure (A). Overall, this study shows that Taguchi method would be among the best method to solve the problem with minimum number of trials.

M.H.I Ibrahim; N. Muhamad; A.B Sulong; K.R. Jamaludin; S. Ahmad; N.H.M Nor

2010-01-01

187

Various high functional sintered materials by injection molding process; Shashutsu seikei process wo mochiita kakushu kokino shoketsu zairyo  

Energy Technology Data Exchange (ETDEWEB)

Since the Metal Injection Molding (MIM) process can offer full dense and net shaping of the three dimensional complicated parts regardless of the soft and hard metals, it can be said that it is one of the new metal processing techniques further advanced to the common power metallurgy process. Authors correctly controlled the amount of carbon and structures by using the new MIM process based on the environmental control during the de-binder (during heat-volatilizing after the solvent extraction) and sintering, finally developed a sintered material with extremely high performance, which was difficult to obtain by the common power metallurgy process. In this paper, the ferrous composite materials showing a good sliding characteristic were introduced by only adding a minority of TiN and CaF2 powers into the MIM sintered alloy steel (various stainless steel, high speed steel, maraging steel, 4100 steel, 4600 steel), high performance soft magnetic steel (Fe-Ni, Fe-Si and Sendust), and low alloy steel developed by using the MIM process. 15 refs., 12 figs., 1 tab.

Miura, H. [Kumamoto Univ. (Japan). Faculty of Engineering

1998-05-15

188

Polyethylene ionomer-based nano-composite foams prepared by a batch process and MuCell injection molding  

International Nuclear Information System (INIS)

[en] To understand the correlation between foamability and melt rheology of polyethylene-based ionomers having different degrees of the neutralization and corresponding nano-composites, we have conducted the foam processing via a batch process in an autoclave and microcellular foam injection molding (FIM) process using the MuCell technology. We have discussed the obtainable morphological properties in both foaming processes. All cellular structures were investigated by using field emission scanning electron microscopy. The competitive phenomenon between the cell nucleation and the cell growth including the coalescence of cell was discussed in light of the interfacial energy and the relaxation rate as revealed by the modified classical nucleation theory and rheological measurement, respectively. The FIM process led to the opposite behavior in the cell growth and coalescence of cell as compared with that of the batch process, where the ionic cross-linked structure has significant contribution to retard the cell growth and coalescence of cell. The mechanical properties of the structural foams obtained by FIM process were discussed.

2010-01-01

189

MECHANICAL PROPERTIES OF INJECTION-MOLDED FOAMED WHEAT STRAW FILLED HDPE BIOCOMPOSITES: THE EFFECTS OF FILLER LOADING AND COUPLING AGENT CONTENTS  

Directory of Open Access Journals (Sweden)

Full Text Available This study investigated the effect of filler loading and coupling agent contents on the densities and mechanical properties of injection-molded foamed biocomposites. Biocomposite pellets were manufactured using wheat straw flour, maleic anhydrite grafted polyethylene (MAPE), paraffin wax, and high-density polyethylene (HDPE) with an extrusion process. Pellets and the chemical foaming agent (azodicarbonamide) were dry-mixed and foamed in an injection-molding machine. Densities and mechanical properties of the foamed biocomposites samples were measured and analyzed using central composite design (CCD). The results showed that both filler loading and coupling agent contents affected the density and mechanical properties of foamed biocomposites. Densities in the range of 0.57 to 0.81 gr cm-3 were achieved. Best results were obtained when less than 20% wheat straw flour and 1% coupling agent content were used. The flexural modulus and tensile modulus of foamed biocomposites were improved with increasing filler loading. However, flexural strength, tensile strength, elongation at break, and impact strength values were diminished. The tensile strength of the biocomposites was positively affected by CA contents, but other mechanical properties were not affected by it. Overall, injection molded foamed biocomposites with moderate mechanical properties were produced.

Fatih Mengeloglu,; Kadir Karaku?

2012-01-01

190

Constante de mola de molas cerâmicas injetadas a baixa pressão/ Spring constant of low-pressure injection molded ceramic springs  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A dificuldade de usinagem de peças cerâmicas já sinterizadas é muito grande, principalmente devido à dureza e fragilidade destes materiais, o que implica em altos custos de produção. Por isso, grandes esforços tem sido feitos no sentido de melhorar os processos de conformação a verde existentes, ou criar novos processos que permitam a obtenção de peças cada vez mais próximas do formato final desejado. Produzir peças cerâmicas com formatos complexos, livres (more) de defeitos, é uma tarefa que implica em grandes dificuldades. Molas cerâmicas possuem formatos extremamente difíceis de serem moldados e, conseqüentemente, atualmente são produzidas comercialmente molas cerâmicas pelo processo de usinagem, geralmente a um custo elevado. Uma alternativa para a produção de molas cerâmicas é a moldagem por injeção em baixa pressão. Para o desenvolvimento de molas cerâmicas para aplicações tecnológicas, é necessário, além de obter peças íntegras e livres de defeitos, aferir algumas de suas propriedades, como a constante de mola. Uma vez que estas molas encontram aplicação em altas temperaturas, torna-se imprescindível realizar a medida da resistência imposta pela mola à deformação elástica em diferentes temperaturas. Para tanto, este trabalho propõem a montagem de um sistema para a medição da constante de mola de molas cerâmicas injetadas a baixa pressão, tanto à temperatura ambiente como em altas temperaturas, usando o método dinâmico da excitação por impulso para medir a frequência de vibração da mola suspensa no interior de um forno. Para ilustrar a aplicação desta técnica são apresentados resultados obtidos para uma mola helicoidal de alumina, da temperatura ambiente até 1100 ºC. Abstract in english The machining of sintered ceramic parts is a difficult process, mainly due to the hardness and brittleness of these materials, which implies in high production costs. Therefore, great efforts have been made to improve the forming processes of green ceramics, or create new processes to obtain the near net shape parts. The production of ceramic parts with complex shapes, free of defects, is a task that involves great difficulties. Ceramic springs exhibits shapes extremely d (more) ifficult to be molded and therefore are currently commercially produced mainly by machining, a process which is difficult and expensive. An alternative for the production of ceramic springs is by low-pressure injection molding. For the development of ceramic springs for technological applications, it is required in addition to getting parts intact and free of defects, to measure some of its properties, including the spring constant. Since these springs are usually applied at high temperatures, it becomes important to carry out the measurement of resistance imposed by the spring to elastic deformation at different temperatures. Accordingly, in this work we describe the assembly of an experiment for the measurement of the spring constant of low-pressure injection molded ceramic springs, both at ambient temperature and at high temperatures, using the dynamic impulse excitation method to measure the frequency of vibration of a suspended spring inside a furnace. Results are presented for a helical spring of alumina from room temperature to1100 ºC to illustrate the application of this technique.

Barbieri, R. A.; Zorzi, J. E.

2011-12-01

191

Glass fiber-reinforced engineering thermoplastics used in the car industry; GF-Thermoplastverbunde im PKW-Bereich  

Energy Technology Data Exchange (ETDEWEB)

Glass fiber reinforced engineering thermoplastics processed by injection molding, or in the form of glass fiber mat-reinforced polypropylenes, are used by the car industry for a wide variety of applications. The paper summarizes the materials and properties, mechanical performance, production variables, and the range of applications. Examples illustrate current applications for weight reduction at BMW as well as economics aspects. (orig./CB) [German] Glasfaserverstaerkte technische Thermoplaste (GF-T) in Form von Spritzguss und glasmattenverstaerktem PP sind heute in zahlreichen Anwendungen des Fahrzeuges zu finden. Einleitend steht ein vergleichender Ueberblick zur Einordnung von GF-T, hinsichtlich Materialaufbau, mechanischer Eigenschaften, Fertigungsparameter und Anwendungsspektrum. Bei BMW eingesetzte GF-T-Technologien wie Spritzguss- und GMT-Technik werden anhand von aktuellen Beispielen vorgestellt. Darueber hinaus werden auch neue bei BMW entwickelte GF-T-Werkstoffsysteme, -Technologien und -Bauweisenkonzepte, die das Potential zum Einsatz im Strukturbereich besitzen, vorgestellt. Die dabei erzielbaren Leichtbaupotentiale und letztendlich die Wirtschaftlichkeit werden abschliessend diskutiert. (orig.)

Mehn, R. [Bayerische Motoren Werke AG (BMW), Muenchen (Germany)

2000-07-01

192

Fabrication and characterization of poly(propylene fumarate) scaffolds with controlled pore structures using 3-dimensional printing and injection molding.  

UK PubMed Central (United Kingdom)

Poly(propylene fumarate) (PPF) is an injectable, biodegradable polymer that has been used for fabricating preformed scaffolds in tissue engineering applications because of in situ crosslinking characteristics. Aiming for understanding the effects of pore structure parameters on bone tissue ingrowth, 3-dimensional (3D) PPF scaffolds with controlled pore architecture have been produced in this study from computer-aided design (CAD) models. We have created original scaffold models with 3 pore sizes (300, 600, and 900 microm) and randomly closed 0%, 10%, 20%, or 30% of total pores from the original models in 3 planes. PPF scaffolds were fabricated by a series steps involving 3D printing of support/build constructs, dissolving build materials, injecting PPF, and dissolving support materials. To investigate the effects of controlled pore size and interconnectivity on scaffolds, we compared the porosities between the models and PPF scaffolds fabricated thereby, examined pore morphologies in surface and cross-section using scanning electron microscopy, and measured permeability using the falling head conductivity test. The thermal properties of the resulting scaffolds as well as uncrosslinked PPF were determined by differential scanning calorimetry and thermogravimetric analysis. Average pore sizes and pore shapes of PPF scaffolds with 600- and 900-microm pores were similar to those of CAD models, but they depended on directions in those with 300-microm pores. Porosity and permeability of PPF scaffolds decreased as the number of closed pores in original models increased, particularly when the pore size was 300 microm as the result of low porosity and pore occlusion. These results show that 3D printing and injection molding technique can be applied to crosslinkable polymers to fabricate 3D porous scaffolds with controlled pore structures, porosity, and permeability using their CAD models.

Lee KW; Wang S; Lu L; Jabbari E; Currier BL; Yaszemski MJ

2006-10-01

193

Synthesis and characterization of thermoplastic polyphenoxyquinoxalines  

Science.gov (United States)

This research was divided into two main parts. In the first part, a new facile route to relatively inexpensive thermoplastic polyphenoxyquinoxalines was developed. The synthetic route involves the aromatic nucleophilic substitution reaction of bisphenols with 2,3-dichloroquinoxaline. The dichloro monomer was prepared in two steps. In the first step, oxalic acid was condensed with o-phenylenediamine to give 2,3-dihydroxyquinoxaline. In the second step, 2,3-dihydroxyquinoxaline was treated with thionyl chloride to give 2,3-dichloroquinoxaline. This monomer was successfully polymerized with bisphenol-A, bisphenol-S, hexafluorobisphenol-A and 9,9-bis(4-hydroxyphenyl)fluorenone. Hydroquinone and biphenol, however, can not be polymerized to high molecular weight polymers because of the premature precipitation of crystalline oligomers. The glass transition temperatures of the high molecular weight polymers prepared from a series of bisphenols range from 191 °C to 279 °C, and their thermal decomposition temperatures are around 500 °C. The polymers are soluble in a wide range of solvents and can be solution-cast into thin films that are colorless and transparent. The polymers have tensile strengths ranging from 61 to 107 MPa, and tensile moduli ranging from 3.5 to 2.3 GPa. The synthesis of polymer obtained from 2,3-dichloroquinoxaline and bisphenol-A was scaled up to afford 500 g of material. This polymer is a thermoplastic with a melt-viscosity less than 1000 Pa.s. at 300 °C. The notched Izod impact strength of injection-molded samples of this polymer is 40.7 J/m. In the second part of this research, the synthetic method has been modified to allow the preparation of quinoxaline containing polyimides. Thus, 2,3-dichloroquinoxaline was treated either with p-nitrophenol followed by reduction of nitro groups, or with p-aminophenols to directly obtain the desired 2,3-(4-aminophenoxy)quinoxaline. This diamine was polymerized with 3,3',4,4'-biphenyldianhydride, 4,4'-oxydiphthalic anhydride and 2,2'-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride. The polymerizations were carried out by the two step method. The poly(amic acid) intermediates were thermally imidized. Although they have high molecular weights judged by their inherent viscosities ranging from 0.51 to 1.01, thin films of all these polyimides were brittle. The glass transition temperatures of the polyimides range from 259 °C to 282 °C with thermal decomposition temperatures around 550 °C. The polyimide obtained from 2,3-(4-aminophenoxy)quinoxaline and 3,3',4,4'-biphenyldianhydride was found to be semi-crystalline.

Erdem, Haci Bayram

194

Application of extrusion-cooking for processing of thermoplastic starch (TPS)  

UK PubMed Central (United Kingdom)

Thermoplastic starch (TPS) as fully biodegradable biopolymer appeared to be one of the most useful and promising materials for packaging purpose. To obtain TPS thermal and mechanical processing should disrupt semi-crystalline starch granules. As the melting temperature of pure starch is substantially higher than its decomposition temperature, there is a necessity to use plasticizers, e.g. a glycerol. Various blends of potato starch mixed with glycerol were extrusion-cooked to obtain different range of TPS pellets, then processed using film blowing and injection molding techniques. Starch modification under high temperature, glass transition temperature, visco-elastic properties of TPS samples (DMTA), the storage modulus E? and loss modulus E? were evaluated for several frequencies. The mechanical properties, the texture and the structure of the obtained materials were measured using standard methods.

Mo?cicki L; Mitrus M; Wójtowicz A; Oniszczuk T; Rejak A; Janssen L

2012-07-01

195

Rapid determination of tensile and flexural strengths of thermoplastics using deep drawing fissure test  

UK PubMed Central (United Kingdom)

A test plate of given shape, thickness and size is made from the thermoplastic, using a pressure injection molding machine and mold. The plate is used to determine the tensile strength and flexural rigidity of the plastic. Preferred features: The test piece is held in a holder under predetermined clamping force. The rounded top end of a plunger is advanced from below against a defined location of the test plate. Advance takes place at set speed. The depth of drawing is measured. Advance is continued, until a deep-drawing crack or fissure appears. A sensor detects the fissure; this monitors the test piece visually and acoustically. The procedure is executed at positions (X1) and (X2) on the test piece, determining the average penetration. Formulae are used to determine tensile strength and flexural rigidity from the mean values.

BUETTCHER MANFRED; SCHULTHEIS KLAUS; SCHWARZ GERHARD

196

Fabrication of high performance sintered alloy steels by metal injection molding. Koseino shoketsu gokinko no kinzoku funmatsu shashutsu seikeiho ni yoru sakusei  

Energy Technology Data Exchange (ETDEWEB)

To fabricate high performance sintered alloy steels, discussions were given on application of the metal injection molding process to a powder mixed to the composition of the 4600 b steel and the A4600V alloy powder, both the powder forging steel species. This paper describes the following matters on the result therefrom: A de-binder method that performs heating and evaporation of wax after extracting it using solvents is suitable for the case where wax-based binders are used: to make carbon amount in the sinters to about 0.4% (a target value), an N2 gas mixture with H2 concentration made to 40% plus may be used as an atmosphere during the heating and evaporation; on the injection molding material using the powder mixture, dense and microfine sintered structure can be formed if the sintering temperature (1573 K) and the atmosphere are controlled adequately; and a sinter with mechanical properties comparable with those for powder forging alloy steel can be obtained if a densifying treatment is given using the Ceracon process. 30 refs., 17 figs., 2 tabs.

Miura, H. (Kumamoto University, Kumamoto (Japan). Faculty of Engineering)

1992-08-20

197

Energy saving by changing hydraulically driven injection molding machine into electric motor driven. Chunyu seikeiki Yuatsu kudo no dendo kudoka ni yoru sho energy  

Energy Technology Data Exchange (ETDEWEB)

An attempt was made on saving energy by changing the driving source of an automotive parts injection molding machine from hydraulic power to electric motor power. In the hydraulic system, a drive source pump is operated continuously, whereas 74.3% of the total energy is not used directly to make products, but wasted as a loss in idle operation. A hydraulic system has a structural difficulty to remarkably reduce this loss, and therefore, it was planned to change the system to electric motor driven, and a new injection molding machine was fabricated using a 4.4 kW AC servo motor as the drive source. As a result, the driving energy cost was reduced from 72,274 yen/year to 5,927 yen/year, a reduction to a one-twelfth level. Elimination of oil leakage measures and hydraulic fluid replacement contributed to enhancing the maintenance requirement, and improving the working environment as a result of reduced noise. However, an increase in the investment from 1.83 million yen per machine to 2.63 million yen leaves a problem of future cost reduction by means of reviewing the drive motor types, and reducing the motor capacity. 5 figs., 2 tabs.

Nakamura, I. (Toyoda Gosei Co. Ltd., Aichi (Japan))

1991-02-04

198

Development of TiAl-type intermetallic compounds by metal powder injection molding process; Kinzoku funmatsu shashutsu seikei ni yoru TiAl kinzokukan kagobutsu no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

Since a TiAl-type intermetallic compound (TiAl) has an excellent high temperature strength and corrosion resistance, in addition to light weight, it is expected to be applicable to the engine parts. However, it is difficult for TiAl to produce a part with a complex shape, and considerable cost will be required. In this study, it was tried to develop a technology for producing TiAl products with high density and high efficiency by using metal powder injection molding (MIM) process. Several kinds of TiAl alloy powders made by the self-propagating high temperature synthesis process were mixed with an organic binder, kneaded and then injection-molded into tensile specimens. These compacts were subjected to the treatment for removing the binder and sintering, resulted in a relative density as high as 97%. By room and high temperature tensile tests, it was found that, Ti-47.4Al-2.6Cr (at%) has the strength and ductility as those of the conventional processed materials. (author)

Terauchi, S.; Teraoka, T.; Shinkuma, T. [Osakayakin Kogyo Co. Ltd., Osaka (Japan); Sugimoto, T. [Kansai University, Osaka (Japan). Faculty of Engineering

2000-12-15

199

Injection molding simulation to improve the efficiency and quality of metal molding designs. Kanagata no sekkei koritsu ka to hinshitsu kojo wo hakaru shashutsu seikei simulation  

Energy Technology Data Exchange (ETDEWEB)

In order to improve the efficiency and quality of metal molding designs, Sony Corp. has adopted an injection molding simulation system since the first half of 1980s. Since, however, molding materials are thermal fluids, which transit their phase from liquid into solid, and boundary conditions will be changed in the middle of their cycles, their analyzing works are very difficult. Therefore, softwares in this field are still on the way to be developed. Since this corporation has joined to the Cornell Injection Molding Program (CIMP) project in Cornell University, they have added improvements on their programs to be supplied, and have used them with their own programs developed additionally based on transformation processes. They have carried out minimizing of shape of boss root and examining holding pressure control by this simulation system. Since actually input works for CAD process have been carried out by hand now, it takes a time a little, though, they have also considered to make it easy by automating for applications of the full model. 4 refs., 7 figs.

Ito, Y. (Sony Corp., Tokyo (Japan))

1992-01-01

200

Moldagem por injeção de pós cerâmicos: remoção da parafina e do polipropileno utilizados como veículo orgânico Ceramic injection molding: removal of pafafin and polypropylene used as organic binder  

Directory of Open Access Journals (Sweden)

Full Text Available A moldagem por injeção de pós cerâmicos tem se tornado um processo altamente atrativo por aliar a versatilidade e a produtividade da moldagem por injeção convencional às propriedades inerentes aos materiais cerâmicos. A remoção do ligante, usado como veículo orgânico nesse processo, é uma das etapas críticas para a produção de peças cerâmicas sem defeitos. Neste trabalho avaliou-se a influência da geometria das peças injetadas na remoção do ligante, tanto por imersão em solvente como por decomposição térmica. Alumina em pó foi misturada fisicamente a um ligante composto por polipropileno [PP], parafina [PW] e ácido esteárico [AE]. As peças com diferentes geometrias foram mantidas imersas em hexano, secas sob vácuo e acompanhada a variação de massa devido à solubilização do PW e AE. A determinação da porosidade das peças, realizada por meio das isotermas de adsorção/desorção de nitrogênio, mostrou um aumento de porosidade de 0,5% volume para aproximadamente 20% volume após a imersão em solvente. A remoção térmica do PP remanescente produziu hidrocarbonetos alifáticos e compostos insaturados, determinados e quantificados por espectroscopia de infravermelho, que permearam a estrutura porosa da peça. A geometria das peças tem grande influência na remoção do ligante, podendo afetar não só a qualidade do produto final, mas também as etapas subseqüentes do processo.Powder injection molding [PIM] has become highly attractive as it combines the versatility and productivity of conventional injection molding processes with the intrinsic properties of metallic and ceramic materials. The removal of organic binder, used as vehicles during the process, is one of the most critical stages in the production of ceramic devices in this process. In this work, the influence from the geometry of the injected part on the removal of the organic binder was evaluated for both solvent immersion and thermal degradation processes. Alumina powder was mixed with an organic binder, comprising polypropylene [PP], paraffin wax [PW] and stearic acid [SA], and injection molded in different geometries. Immersion of ceramic parts in hexane induced the solubilization of PW and SA, confirmed by weight variation. Parts porosity, determined through nitrogen adsorption isotherm, showed an increase from 0.5 v% before immersion to ca. 20 v% after immersion. PP burnout produced aliphatic hydrocarbons and unsaturated compounds that flow through a porous structure produced in early stages of this process. Parts geometry plays an important role in binder removal, affecting the quality of the sintered part as well as the remaining stages of the process.

Ricardo V. B. Oliveira; Eduardo A. Pinheiro; Valdir Soldi; Alfredo T. N. Pires; Márcio C. Fredel

2004-01-01

 
 
 
 
201

The effect of injection molding conditions on the near-surface rubber morphology, surface chemistry, and adhesion performance of semi-crystalline and amorphous polymers  

Science.gov (United States)

This thesis investigated the effect of injection molding processing variables, resin formulation and mold material on the resulting morphology and properties of semi-crystalline and amorphous polymers in parts molded on large presses with fully developed flow. Five different polymer resins and two different coating types were investigated, and the near-surface morphology was found to be dependent on material formulation, processing parameters, and geometry. For painted TPO, changes in the near-surface rubber morphology and surface chemistry based on material and processing conditions had no significant effect on the adhesion performance. For metal plated ABS, the adhesion performance was found to be heavily dependent on the rubber surface morphology, which varied with material formulation and processing conditions. One of the most significant findings was that forged aluminum injection molding tooling had little effect on the surface morphology or adhesion performance of either polypropylene or the two TPO formulations examined, despite the five-fold increase in thermal conductivity over traditional tool steel. Surface chemistry, however, was found to be affected by cooling rate, depending on material formulation. A UV stabilizer additive was found concentrated at 2.5 atomic percent on the surface of the aluminum molded part, but not the steel molded part, demonstrating a possible opportunity for using additives and aluminum tooling to create "designer surfaces". Processing conditions were found to have a competing role in metal plated ABS, where conditions that lowered surface stress and improved adhesion by a factor of 15 also increased the amount of bulk molded-in stress by nearly 7%. Both factors were found to play an important role in adhesion performance due to the effect of surface stress on the quality of the resulting etch structure. The bulk stress must be minimized to due to the large mechanical and thermal mismatch between the polymer and metal layers. This work provides a more in-depth understanding of the effect of processing and material composition on morphology, surface chemistry, molded-in stress and adhesion. This will establish guidelines for future injection molded part designs to alleviate delamination failures and minimize warp, as well as contribute to modeling predictions of shrink and mechanical behavior.

Weakley-Bollin, Shannon Christine

202

Effect of thermal history on the rheology of thermoplastic polyurethanes  

Science.gov (United States)

The effect of thermal history on the rheological behavior of ester- and, ether-based commercial thermoplastic polyurethanes (TPUs) was investigated. It was found from 1H and 13C nuclear magnetic resonance (NMR) spectroscopy that the ester-based TPU consisted of 4,4'-diphenylmethane diisocyanate (MDI) and butane diol (BDO) as hard segments and poly(butylene adipate) as soft segments, and the ether-based TPU consisted of MDT-BDO as hard segments and poly(oxytetramethylene) as soft segments. During isothermal annealing, the dynamic storage and loss moduli (G' and G'' ) of specimens, which had been prepared by injection molding at different temperatures, were monitored at a fixed angular frequency. It was found that thermal history of specimens had a profound influence on the variations of G' and G' ' with time observed during isothermal annealing. Isochronal dynamic temperature sweep experiments indicated that the TPUs exhibit hysteresis effect during heating and cooling, very similar to that observed in microphase-separated block polymers and thermotropic liquid-crystalline polymers reported in the literature. It was found that time-temperature superposition failed to produce reduced (or master) plots for the TPUs employed. This conclusion was reinforced by the temperature dependence of log G ' versus log G'' plots over the entire range of temperatures (110--190°C) investigated, suggesting that the morphological state of the TPU specimens varied with temperature. Little evidence was found from differential scanning calorimetry that thermal transitions took place in the TPU specimens during isothermal annealing, while values of G' and G' ' were found to vary with time. Measurements were taken of N-H stretching absorption bands in the Fourier transform infrared (FTIR) spectra during isothermal annealing at 170°C for specimens prepared by injection molding at different temperatures. The analysis of FTIR spectra indicated that variations of hydrogen bonding with time during isothermal annealing resemble very much variations of G' with time during isothermal annealing. Little evidence was found from 1H and 13C NMR spectroscopy that exchange reactions took place in the TPU specimens during isothermal annealing at elevated temperatures. It is concluded from the present study that microphase separation transition or order-disorder transition in TPU cannot be determined from oscillatory shear rheometry.

Yoon, Pil Joong

203

Microwavable thermoplastic containers  

UK PubMed Central (United Kingdom)

A multi-layer container suitable for use in microwave cooking of food comprising a substrate layer of a thermoplastic polymer that is not suitable for contact with foods or hot foods, and an inner protective layer designed to contact the food, said inner layer comprising a blend of a styrene/maleic anhydride copolymer and a polymer selected from the group consisting of polystyrene, rubber modified polystyrene, polymethyl methacrylate, rubber modified polymethyl methacrylate, polypropylene, and mixtures thereof.

HATHAWAY PAUL E; WAGNER PHILLIP A

204

Thermoplastics containing antiphlogistics  

UK PubMed Central (United Kingdom)

1. Thermoplastics containing antiinflammatory agents for cannulas, catheters, tubes, artificial blood vessels, implants, heart valves and films, which can be produced from thermoplastics from the group comprising polyolefines, styrene polymers, polyvinyl halides, polycarbonates, polyesters, polyamides, polyphenylene oxides, polyacetals, cellulose esters or polyurethanes and copolymers of the abovementioned polymers and antiinflammatory agents of the formula see diagramm : EP0132690,P13,F1 wherein R**1 to R**5 represent hydrogen, halogen, lower alkyl or substituted alkyl, X represents N or CH and Y represents hydrogen, metal ions, alkyl or substituted alkyl, and/or of the formula see diagramm : EP0132690,P13,F2 wherein R represents hydrogen, lower alkyl or substituted alkyl, Ar represents aryl, heteroaryl, substituted aryl or substituted heteroaryl and n + m denote an integer and have the value zero, 1 or 2 and p denotes zero or 1, with the proviso that Ar does not denote aryl or heteroaryl if m + n and p have the value zero, and esters or amides thereof, and/or of the formula see diagramm : EP0132690,P13,F3 wherein R**6 and R**7 together form an aryl or heteroaryl ring with an N atom, R**8 represents a lower alkyl group with 1-4 C atoms and R**9 represents a heteroaryl radical with at least one heteroatom, wherein the components have been mixed in an extruder and then homogenized, in a temperature range at which the thermoplastic plasticizes and the antiinflammatory agent is in liquid form.

Dell Hans-Dieter Dr.; Pelster Eberhard Dr.; Wirzbach Eberhard; Burgdörfer Hans-Heribert Dr.; Ascherl Rudolf Dr.

205

Morphology of wood species affecting wood-thermoplastic interaction: microstructure and mechanical adhesion  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english The main objective of the research presented here is to relate anatomical features of wood species that affect the interactions between polymeric phases and performance of wood plastic composites (WPC). These interactions are related to the probable interlocking volume and surface area for stress transfer in a WPC. Composites were produced from different wood species and analyzed using SEM (scanning electron microscopy). Results showed that wood species with high interfac (more) ial areas may increase mechanical interlocking, reflected in the viscous constant of the Maxwell model. A complicating factor is that the relation of cell wall thickness-lumen diameter and the interconnectivity between wood cells in a wood, affect the potential for cell collapse. When wood cells collapse, the penetration of the thermoplastic into the wood structure is almost always ceased. The collapse of wood cells during extrusion-injection molding processes reduced the potential surface for stress transfer between phases affecting the mechanical properties of composites. Undamaged wood cells may potentially be filled with HDPE thermoplastic enhancing modulus and increase the strength of WPC.

Gacitua, William; Wolcott, Michael

2009-01-01

206

Morphology of wood species affecting wood-thermoplastic interaction: microstructure and mechanical adhesion  

Directory of Open Access Journals (Sweden)

Full Text Available The main objective of the research presented here is to relate anatomical features of wood species that affect the interactions between polymeric phases and performance of wood plastic composites (WPC). These interactions are related to the probable interlocking volume and surface area for stress transfer in a WPC. Composites were produced from different wood species and analyzed using SEM (scanning electron microscopy). Results showed that wood species with high interfacial areas may increase mechanical interlocking, reflected in the viscous constant of the Maxwell model. A complicating factor is that the relation of cell wall thickness-lumen diameter and the interconnectivity between wood cells in a wood, affect the potential for cell collapse. When wood cells collapse, the penetration of the thermoplastic into the wood structure is almost always ceased. The collapse of wood cells during extrusion-injection molding processes reduced the potential surface for stress transfer between phases affecting the mechanical properties of composites. Undamaged wood cells may potentially be filled with HDPE thermoplastic enhancing modulus and increase the strength of WPC.

William Gacitua; Michael Wolcott

2009-01-01

207

Bonding thermoplastic polymers  

Energy Technology Data Exchange (ETDEWEB)

We demonstrate a new method for joining patterned thermoplastic parts into layered structures. The method takes advantage of case-II permeant diffusion to generate dimensionally controlled, activated bonding layers at the surfaces being joined. It is capable of producing bonds characterized by cohesive failure while preserving the fidelity of patterned features in the bonding surfaces. This approach is uniquely suited to production of microfluidic multilayer structures, as it allows the bond-forming interface between plastic parts to be precisely manipulated at micrometer length scales. The bond enhancing procedure is easily integrated in standard process flows and requires no specialized equipment.

Wallow, Thomas I. (Fremont, CA); Hunter, Marion C. (Livermore, CA); Krafcik, Karen Lee (Livermore, CA); Morales, Alfredo M. (Livermore, CA); Simmons, Blake A. (San Francisco, CA); Domeier, Linda A. (Danville, CA)

2008-06-24

208

Design, assembly, and optical bench testing of a high-numerical-aperture miniature injection-molded objective for fiber-optic confocal reflectance microscopy.  

UK PubMed Central (United Kingdom)

The design, analysis, assembly methods, and optical-bench test results for a miniature injection-molded plastic objective lens used in a fiber-optic confocal reflectance microscope are presented. The five-lens plastic objective was tested as a stand-alone optical system before its integration into a confocal microscope for in vivo imaging of cells and tissue. Changing the spacing and rotation of the individual optical elements can compensate for fabrication inaccuracies and improve performance. The system performance of the miniature objective lens is measured by use of an industry-accepted slanted-edge modulation transfer function (MTF) metric. An estimated Strehl ratio of 0.61 and a MTF value of 0.66 at the fiber-optic bundle Nyquist frequency have been obtained. The optical bench testing system is configured to permit interactive optical alignment during testing to optimize performance. These results are part of an effort to demonstrate the manufacturability of low-cost, high-performance biomedical optics for high-resolution in vivo imaging. Disposable endoscopic microscope objectives could help in vivo confocal microscopy technology mature to permit wide-scale clinical screening and detection of early cancers and precancerous lesions.

Chidley MD; Carlson KD; Richards-Kortum RR; Descour MR

2006-04-01

209

Cosintering of Powder Injection Molding Parts Made from Ultrafine WC-Co and 316L Stainless Steel Powders for Fabrication of Novel Composite Structures  

Science.gov (United States)

Sintering response and phase formation during sintering of WC-Co/316L stainless steel composites produced by assembling of powder injection molding (PIM) parts were studied. It is shown that during cosintering a significant mismatch strain (>4 pct) is developed in the temperature range of 1080 °C to 1350 °C. This mismatch strain induces biaxial stresses at the interface, leading to interface delamination. Experimental results revealed that sintering at a heating rate of 20 K/min could be used to decrease the mismatch strain to M6C carbides at 1220 °C. Spreading of the liquid accelerates the reaction, affecting the dimensional stability of the PIM parts. To prevent the reaction, surface oxidation of the cemented carbide followed by hydrogen reduction during sintering was examined. Although the amount of mismatch strain increased, formation of a metallic interface consisting of a W-Co alloy (45 to 50 at. pct Co) and a Co-rich iron alloy (18 at. pct Co) prevented the decomposition of WC and melt formation. It is also shown that the deposition of a thin Ni layer after thermal debinding decreases the mismatch stresses through melt formation, although interlayer diffusion causes pore-band formation close to the steel part.

Simchi, A.; Petzoldt, F.

2010-01-01

210

Numerical simulation of transport processes in injection mold-filling during production of a cylindrical object under isothermal and non-isothermal conditions  

Energy Technology Data Exchange (ETDEWEB)

In this paper, numerical simulation of injection mold-filling during the production of a cylindrical object under isothermal and non-isothermal conditions is presented. The material of the object is low density polyethylene (LDPE) following power-law viscosity model for non-zero shear rate zone. However, where shear rate becomes zero, zero-shear viscosity value has been used. Three cases have been considered, namely (1) Isothermal filling at constant injection pressure, (2) Isothermal filling at constant flow rate, and (3) Non-isothermal filling at constant flow rate. For the case-(3), the viscosity of LDPE is also a function of temperature. The material of the mold is steel. For the non-isothermal filling, the concept of melt-mold thermal contact resistance coefficient has been incorporated in the model. The length and diameter of the body in all three cases have been taken as 0.254 m and 0.00508 m respectively. The finite-difference method has been used to solve the governing differential equations for the processes. The results show excellent agreement with the corresponding equations for the processes. The results show excellent agreement with the corresponding analytical solutions for the first two cases showing the correctness of the numerical method. The simulation results for non-isothermal filling show physically realistic trends and lend insight into various important aspects of mold-filling including frozen skin layer.

Kumar, A.; Ghoshdastidar, P.S.

1999-07-01

211

Peri-implant bone formation and surface characteristics of rough surface zirconia implants manufactured by powder injection molding technique in rabbit tibiae.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To evaluate osseointegration in rabbit tibiae and to investigate surface characteristics of novel zirconia implants made by powder injection molding (PIM) technique, using molds with and without roughened inner surfaces. MATERIAL AND METHODS: A total of 20 rabbits received three types of external hex implants with identical geometry on the tibiae: machined titanium implants, PIM zirconia implants without mold etching, and PIM zirconia implants with mold etching. Surface characteristics of the three types of implant were evaluated. Removal torque tests and histomorphometric analyses were performed. RESULTS: The roughness of PIM zirconia implants was higher than that of machined titanium implants. The PIM zirconia implants exhibited significantly higher bone-implant contact and removal torque values than the machined titanium implants (P < 0.001). The PIM zirconia implants using roughened mold showed significantly higher removal torque values than PIM zirconia implants without using roughened mold (P < 0.001). CONCLUSIONS: It is concluded that the osseointegration of PIM zirconia implant is promising and PIM using roughened mold etching technique can produce substantially rough surfaces on zirconia implants.

Park YS; Chung SH; Shon WJ

2013-05-01

212

Research cooperation project on the development of easy injection molding control technology for engineering plastics; Engineering plastic no seikei joken kan`i settei gijutsu ni kansuru kenkyu kyoryoku jigyo seika hokokusho  

Energy Technology Data Exchange (ETDEWEB)

In order to enhance the industries which supply assembly parts to Japan`s assembly industries in Thailand, research cooperation project on the plastic parts production technology has started. For the research cooperation, the mold design is effectively conducted using simulation technique of CAE (computer aided engineering), and an international easy injection molding control system is made using the molding support software for injection molding machines. In FY 1996, actual situations of plastic parts and assembly industries in Thailand have been investigated through the cooperation with the counterpart of Thailand. Demand and supply of engineering plastics, receive and inspection of parts, and current circumstances of molding processing makers in Thailand have been grasped. Based on the results of this investigation, proposal of basic plan, time schedule, and delivery plan of molding machines and testing equipment have been discussed, to make the basic plan. 18 refs., 4 figs., 23 tabs.

NONE

1997-03-01

213

Irradiated thermoplastic elastomer  

International Nuclear Information System (INIS)

[en] A thermoplastic elastomer which is processable after irradiation comprises a diblock copolymer which is irradiated at a dose level of from about 0.1 to about 3.0 times the gel dose. The resulting diblock copolymer elastomer has improved physical strength and is readily processable. The diblock copolymer has one block portion made from an olefin having from 2 to 12 carbon atoms, a conjugated diene having from 4 to 12 carbon atoms, or combinations thereof. The remaining block portion is made from vinyl aromatic monomers having from 3 to 15 carbon atoms. A triblock copolymer may be added to the diblock copolymer to form a blend which is irradiated at the same dose level. The triblock copolymer has a central block portion which is also made from the above-noted olefins, conjugated dienes, or combinations thereof, and end portions which are also made from the above-noted vinyl aromatic monomers. (Auth.)

1977-01-25

214

Determinação da redução da resistência à tração em corpos de prova com Weld Line/ Determination of reduction of the weld line strength in injection molded  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Neste trabalho objetivou-se determinar a redução da resistência à tração de corpos de prova com linhas de solda. Os corpos de prova ASTM foram moldados pelo processo de injeção com diferentes temperaturas de plastificação (180 ºC a 280 ºC). O material utilizado foi o polímero termoplástico Polystyrol 158 K da Basf. Este estudo relaciona as linhas de solda em produtos moldados por injeção com a redução da resistência mecânica devido a fragilização na (more) região da linha de solda. Para o desenvolvimento deste trabalho foi projetado e desenvolvido um molde de injeção com uma cavidade em forma de corpo de prova com canal de ataque pelas extremidades. Desta forma no momento da junção dos fluxos obtêm-se uma linha de solda no centro do corpo de prova. Os parâmetros do processo de injeção foram determinados a partir de um aplicativo comercial. A temperatura do molde e o tempo de injeção permaneceram constantes. O tempo de solidificação do material foi determinado analiticamente, considerando-se o centro do corpo de prova como referência. Foram injetados dez corpos de prova em cada uma das temperaturas. Foi observada de forma clara a existência de linhas de junção no centro da peça e as condições de processo utilizadas não permitiram a formação de linha de solda fria. Após a realização dos ensaios de tração, foi determinado que a tensão de ruptura decresce nas seguintes condições: com a diminuição da temperatura de injeção e do tempo de solidificação e com o aumento da trinca. A ruptura sempre ocorreu na linha de solda. Abstract in english In this paper, the purpose is to determine the weld line strength in injection molded samples. The ASTM standard dogbone-shaped samples were molded over a range of melt temperatures (180 ºC up to 280 ºC). The plastic used was a commercial grade of polystyrene (PS), BASF Polystyrol 158K. This study links weld lines in parts by injection molding with mechanical strength reduction due to embrittling effect in weld-line region. A single-cavity mold double-gated was used to (more) generate ASTM D638 Type I tensile specimens. The double-gated and runner allow the parts to be molded with weld line. The injection process parameters were determined by imputing resin, machine and geometry information into a CAE software package. The mold temperature and fill time were maintaining the same. The frozen time was determined by analytic equation, which considers the center of the thickness as reference. For each melt temperature 10 samples were tested. The weld line was clearly noted in the centre of the samples and the process condition set avoided the cold weld line. By the strength tests were possible to realize that lower the injection temperature lower the frozen time and higher the length of the crack. Then low injection temperature leads to low maximum strength. The fracture always occurs in the weld line.

Bom, R.P.; Kalin, A.F.

2008-06-01

215

Aplicação das técnicas de planejamento e análise de experimentos no processo de injeção plástica Application design of experiments in the injection molding process  

Directory of Open Access Journals (Sweden)

Full Text Available Experimentos industriais são realizados pelas empresas com o intuito de melhorar o desempenho dos produtos e os processos de fabricação. Nesse sentido, este trabalho tem por objetivo estudar e aplicar as técnicas de planejamento e análise de experimentos na melhoria da qualidade industrial. Especificamente são aplicadas as técnicas de planejamento Fatorial Fracionado 2k-p, Metodologia de Superfície de Resposta e Análise de Variância, em um processo de moldagem por injeção plástica. Com essa pesquisa experimental foi possível identificar os níveis ótimos de regulagem e os parâmetros mais importantes da injeção plástica: temperatura da máquina e pressão de injeção. Para finalizar é avaliado o procedimento de implementação das técnicas de experimentação e as dificuldades práticas encontradas na empresa.Industrial experiments are made by companies in order to improve the quality characteristics of products and production processes. In this sense, the objective of this paper is to study and apply the design of experiments in the industrial quality improvement. In addition, as a part of the objective, an application of the techniques of design Fractional Factorial 2k-p, Analysis of Variance and Response Surface Methodology is done. It is focused in an injection molding process applied by a company, that makes and trades plastic products for the civil construction. Using this experimental study, the most important parameters of plastic injection are identified: machine temperature and injection pressure. At the same time, the optimal levels of adjustment of these parameters are determined. From this study, it is evaluated both the implantation procedures of the designs of experiments as well as the difficulties faced. Also, this study tries to contribute to the university-company relationship.

Edwin V. Cardoza Galdamez; Luiz C. Ribeiro Carpinetti

2004-01-01

216

Thermoplastic tape compaction device  

Science.gov (United States)

A device is disclosed for bonding a thermoplastic tape to a substrate to form a fully consolidated composite. This device has an endless chain associated with a frame so as to rotate in a plane that is perpendicular to a long dimension of the tape, the chain having pivotally connected chain links with each of the links carrying a flexible foot member that extends outwardly from the chain. A selected number of the foot members contact the tape, after the heating thereof, to cause the heated tape to bond to the substrate. The foot members are each a thin band of metal oriented transversely to the chain, with a flexibility and width and length to contact the tape so as to cause the tape to conform to the substrate to achieve consolidation of the tape and the substrate. A biased leaf-type spring within the frame bears against an inner surface of the chain to provide the compliant pressure necessary to bond the tape to the substrate. The chain is supported by sprockets on shafts rotatably supported in the frame and, in one embodiment, one of the shafts has a drive unit to produce rotation such that the foot members in contact with the tape move at the same speed as the tape. Cooling jets are positioned along the frame to cool the resultant consolidated composite. 5 figures.

Campbell, V.W.

1994-12-27

217

Thermoplastic tape compaction device  

Energy Technology Data Exchange (ETDEWEB)

A device for bonding a thermoplastic tape to a substrate to form a fully consolidated composite. This device has an endless chain associated with a frame so as to rotate in a plane that is perpendicular to a long dimension of the tape, the chain having pivotally connected chain links with each of the links carrying a flexible foot member that extends outwardly from the chain. A selected number of the foot members contact the tape, after the heating thereof, to cause the heated tape to bond to the substrate. The foot members are each a thin band of metal oriented transversely to the chain, with a flexibility and width and length to contact the tape so as to cause the tape to conform to the substrate to achieve consolidation of the tape and the substrate. A biased leaf-type spring within the frame bears against an inner surface of the chain to provide the compliant pressure necessary to bond the tape to the substrate. The chain is supported by sprockets on shafts rotatably supported in the frame and, in one embodiment, one of the shafts has a drive unit to produce rotation such that the foot members in contact with the tape move at the same speed as the tape. Cooling jets are positioned along the frame to cool the resultant consolidated composite.

Campbell, Vincent W. (Oak Ridge, TN)

1994-01-01

218

Embranquecimento do polipropileno isotático injetado contendo TiO2 como pigmento Whitening mechanism in injection molded polypropylene with TiO2 as pigment  

Directory of Open Access Journals (Sweden)

Full Text Available Descrevemos neste trabalho as causas e o mecanismo do embranquecimento de peças de polipropileno isotático injetado. Para isto foram injetados corpos de prova e placas com e sem estabilizantes. As amostras foram envelhecidas por exposição ambiental e em equipamento de envelhecimento acelerado (Weatherometer). Foi feito o acompanhamento visual das peças para que pudessem ser caracterizadas quando começassem a embranquecer. A caracterização foi feita através de espectroscopia FT-IR por reflectância, Microscopia eletrônica de varredura, Microfluorescência de raios-X, Reflectância de luz e Microanálise de energia dispersiva (EDS) da superfície. Os espectros de infravermelho mostraram o aparecimento de diversos produtos de degradação como cetonas, aldeídos, ácidos carboxílicos, ésteres, perésteres e alfa-cetoésteres. Quando as amostras começaram a embranquecer foi verificada a formação de fissuras superficiais e o aumento da reflectância de luz para todos os comprimentos de onda do espectro. Concomitantemente foi verificado que a composição de superfície não é alterada pelo envelhecimento. A superfície não apresenta grande quantidade de partículas de TiO2 expostas. Conclui-se que o embranquecimento das peças é devido ao fissuramento superficial que aumenta a quantidade de luz refletida na superfície e não pela migração do pigmento.We studied in this work the whitening mechanism in injection molded polypropylene (PP), a problem usually manifested in car parts and particularly in car bumpers. For the development of this work we had samples (plaques and test samples) with and without antioxidants and ultraviolet stabilizers. These samples had been already aged by natural and artificial (Weatherometer equipment) exposure. In the natural aging samples were collected when the material started to whiten, after 3190, 4320 and 6190 h of exposure. In the artificial aging samples were collected after 415, 515 and 3000 h of exposure. The samples were characterized by visual observation, infrared spectroscopy, scanning electron microscopy, surface total light reflectance and titanium mapping in the samples cross section by X-ray microfluorescence and X-ray difraction of the TiO2 used in the formulation. When the samples start to whiten we observe the evolution of surface fissures which increase the surface roughness. This is followed by an increase in the total light reflection by the surface for all wavelengths. We observed that titanium is almost homogeneously distributed along samples cross section. In addition, we did not observe high concentration of exposed TiO2 on the surface. We conclude that the whitening phenomenon is a consequence of surface fissures evolution, which provides higher surface roughness and is followed by a higher surface diffuse light reflectance.

Dênison R. J. Maia; Marco-Aurelio De Paoli

2000-01-01

219

Embranquecimento do polipropileno isotático injetado contendo TiO2 como pigmento/ Whitening mechanism in injection molded polypropylene with TiO2 as pigment  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Descrevemos neste trabalho as causas e o mecanismo do embranquecimento de peças de polipropileno isotático injetado. Para isto foram injetados corpos de prova e placas com e sem estabilizantes. As amostras foram envelhecidas por exposição ambiental e em equipamento de envelhecimento acelerado (Weatherometer). Foi feito o acompanhamento visual das peças para que pudessem ser caracterizadas quando começassem a embranquecer. A caracterização foi feita através de esp (more) ectroscopia FT-IR por reflectância, Microscopia eletrônica de varredura, Microfluorescência de raios-X, Reflectância de luz e Microanálise de energia dispersiva (EDS) da superfície. Os espectros de infravermelho mostraram o aparecimento de diversos produtos de degradação como cetonas, aldeídos, ácidos carboxílicos, ésteres, perésteres e alfa-cetoésteres. Quando as amostras começaram a embranquecer foi verificada a formação de fissuras superficiais e o aumento da reflectância de luz para todos os comprimentos de onda do espectro. Concomitantemente foi verificado que a composição de superfície não é alterada pelo envelhecimento. A superfície não apresenta grande quantidade de partículas de TiO2 expostas. Conclui-se que o embranquecimento das peças é devido ao fissuramento superficial que aumenta a quantidade de luz refletida na superfície e não pela migração do pigmento. Abstract in english We studied in this work the whitening mechanism in injection molded polypropylene (PP), a problem usually manifested in car parts and particularly in car bumpers. For the development of this work we had samples (plaques and test samples) with and without antioxidants and ultraviolet stabilizers. These samples had been already aged by natural and artificial (Weatherometer equipment) exposure. In the natural aging samples were collected when the material started to whiten, (more) after 3190, 4320 and 6190 h of exposure. In the artificial aging samples were collected after 415, 515 and 3000 h of exposure. The samples were characterized by visual observation, infrared spectroscopy, scanning electron microscopy, surface total light reflectance and titanium mapping in the samples cross section by X-ray microfluorescence and X-ray difraction of the TiO2 used in the formulation. When the samples start to whiten we observe the evolution of surface fissures which increase the surface roughness. This is followed by an increase in the total light reflection by the surface for all wavelengths. We observed that titanium is almost homogeneously distributed along samples cross section. In addition, we did not observe high concentration of exposed TiO2 on the surface. We conclude that the whitening phenomenon is a consequence of surface fissures evolution, which provides higher surface roughness and is followed by a higher surface diffuse light reflectance.

Maia, Dênison R. J.; De Paoli, Marco-Aurelio

2000-12-01

220

New melt-processable thermoplastic polyimides for opto-electronic applications  

Science.gov (United States)

The rapid development and adoption of digital technology is leading to an increase in demand for smaller, faster digital data devices and faster digital telecommunication networks. This trend requires increased network bandwidth to handle large amounts of data and seamless integration of network devices with compatible end-user devices. This need is being met by using fiber-optic and photonics technology, infra-red (IR) signals to transmit information, and is fundamental changing the communication industry, thereby creating a need for new polymeric materials. New ULTEM* polyetherimide (PEI) and EXTEM* thermoplastic polyimide (TPI) resins meet the material requirements for the optoelectronics industry. These resins have building blocks enabling IR light transmission without degrading signal quality. They can be injection-molded into thin, precision optical lenses and connectors. ULTEM* resins are been widely used in this industry as fiber-optic components in trans-receivers. EXTEM* resins are amenable to lead-free soldering (LFS), a greener industrial assembly process. While still being IR-transparent, EXTEM* resin is an ideal material for LFS capable substrates, connectors and lenses. An optical product portfolio has been developed and is being presented as a solution to the opto-electronics component industry and some of the successful applications therein.

Narayanan, Aditya; Haralur, Gurulingamurthy

2012-10-01

 
 
 
 
221

Properties of Blends of Novatein Thermoplastic Protein from Bloodmeal and Polybutylene Succinate Using Two Compatibilizers  

Directory of Open Access Journals (Sweden)

Full Text Available The use of dual compatibilizers, poly (2-ethyl-2-oxazoline) (PEOX) and polymeric methylene diphenyl diisocyanate (pMDI) in Novatein thermoplastic protein from bloodmeal (NTP) and PBS blends were investigated. A composition of 50% of NTP was used for all formulations with different percentage compatibilizer. Mechanical, morphology, thermal and water absorption were used as analysis methods to study blend properties. To improve compatibility, two different approaches to blending the compatibilizers were used. Firstly, PEOX was added before extrusion this has improved the blend’s tensile strength. Secondly, addition of PEOX during NTP production followed by pMDI added before injection molding, showed a futher improvement in tensile strength. SEM revealed that PEOX has improved the dispersion of NTP and pMDI has strengthened the adhesion between phases consistent with mechanical property results. A broad tan ? peak in DMA analysis was obtained indicated improved compatibility in blends using two compatibilizers. In spite of that, the addition of dual compatibilizer has reduced the water resistance of PBS.

K. I. Ku Marsilla; C. J. R. Verbeek

2013-01-01

222

Structure and thermoplasticity of coal  

Energy Technology Data Exchange (ETDEWEB)

Chapters cover: molecular structure and thermoplastic properties of coal; {sup 1}H-nmr study of relaxation mechanisms of coal aggregate; structural changes of coal macromolecules during softening; quantitative estimation of metaplsat in heat-treated coal by solvent extraction; effects of surface oxidation on thermoplastic properties of coal; analysis of dilatation and contraction of coal during carbonization; formation mechanisms of coke texture during resolidification; modified CPD model for coal devolatilization; mathematical modelling of coke mechanical structure; and simulating particulate dynamics in the carbonization process based on discrete element treatment.

Komaki, I.; Itagaki, S.; Miura, T. (eds.)

2004-07-01

223

Thermoplastic starch materials prepared from rice starch  

International Nuclear Information System (INIS)

[en] Rice starch is a source still little studied for the preparation of thermoplastic materials. However, its characteristics, such as the presence of proteins, fats and fibers may turn into thermoplastics with a better performance. The present study intends the evaluation of the viability of making starch thermoplastic from rice starch and glycerol as plasticizer. The results of X-ray diffraction and scanning electronic microscopy demonstrate the thermoplastic acquisition. The increase of plasticizer content brings on more hydrophilic thermoplastics with less resistance to tension and elongation at break. (author)

2009-01-01

224

Study on forming method of fine ceramics powder by slip casting and low pressure injection molding. Fine ceramics funtai no slip castter dot teiatsu idashi seikeiho ni kansuru kenkyu  

Energy Technology Data Exchange (ETDEWEB)

Slip casting and low pressure injection molding were tested as forming methods of fine ceramics powder, and the results are described in this report. In the slip casting method, selection of a binder which gives plasticity to the green body is important. In case of slip casting of Si {sub 3} N {sub 4} powder with PVA as a binder, plasticity of the compact increased and higher strength was obtained after sintering. Then, a method to apply high pressure to the slurry was examined in order to shorten the casting time of slip casting. It was found that the casting time was shortened appropriately and drying shrinkage was decreased by applying pressure up to 200kgf/cm {sup 2}. Moreover, strength of the alumina compact was investigated by the low pressure injection molding method with a paraffin wax binder at 80-100 centigrade under the pressure of 3-5 atm. When the slurry prepared by the ball mill was formed in the vertical mold, such good results as mean flexural strength of 46kgf/mm {sup 2} with Weibull constant of 14.5 were obtained. 4 refs., 10 figs.

Miyamoto, H. (Osaka Prefectural Industrial Technology Research Inst., Osaka (Japan))

1990-07-25

225

Diamond turning of thermoplastic polymers  

Energy Technology Data Exchange (ETDEWEB)

Single point diamond turning studies were made using a series of thermoplastic polymers with different glass transition temperatures. Variations in surface morphology and surface roughness were observed as a function of cutting speed. Lower glass transition temperatures facilitate smoother surface cuts and better surface finish. This can be attributed to the frictional heating that occurs during machining. Because of the very low glass transition temperatures in polymeric compared to inorganic glasses, the precision machining response can be very speed sensitive.

Smith, E.; Scattergood, R.O.

1988-12-01

226

Microstructure of thermoplastic starch polymers  

Directory of Open Access Journals (Sweden)

Full Text Available Environmental problems with conventional packaging materials developed the need of searching for new alternatives. Thermoplastic starch polymer (TPS) has been found to be a good source of raw materials for new packaging materials. In the paper changes of microstructure of TPS produced from different type of starch with glycerol content have been discussed. In general it can be stated that an increase of glycerol content in the mixture improves material structure quality.

M. Mitrus

2006-01-01

227

In vitro evaluation of long-term cytotoxic response of injection-molded polyamide and polymethyle metacrylate denture base materials on primary fibroblast cell culture.  

Science.gov (United States)

Abstract Objective. This study investigated the long-term cytotoxic response of thermoplastic polyamide and conventional polymethyle metacrylate (PMMA) denture base materials. Materials and ethods. Twenty discs were prepared for each polyamide, heat and cold cured PMMA denture base resins (totally 60) and divided into four sub-groups (n = 5). Cytotoxicity was assessed with the direct cell contact method using cell viability and neutral red (NR) uptake assay. Each sub-group was tested at initial and after being aged for 24 h, 1 week and 8 weeks with artificial saliva according to ISO 10993 standards. Results. There were no significantly difference among the materials and control groups after initial, 24 h and 1 week testing. In 24 h testing, only Deflex was more toxic according to the Control group (p < 0.05). After 8 weeks of aging with artificial saliva, all materials were significantly cytotoxic when compared to the control group. QC20 was more toxic than Deflex and SC Cold Cure (p < 0.05). There were significant differences between the 8 week aging group and the initial, 24 h and 1 week testing for all materials (p < 0.05). Conclusions. Cytotoxicity of all tested denture base materials increased significantly after the long-term aging. Therefore, long-term aging may be useful to determine a dental material's toxicity. Polyamide denture base material had a similar toxicity profile with conventional heat- and cold-cured PMMA. PMID:23998515

Uzun, Ismail Hakki; Tatar, Abdulgani; Hacimuftuoglu, Ahmet; Saruhan, Fatih; Bayindir, Funda

2013-07-03

228

In vitro evaluation of long-term cytotoxic response of injection-molded polyamide and polymethyle metacrylate denture base materials on primary fibroblast cell culture.  

UK PubMed Central (United Kingdom)

Abstract Objective. This study investigated the long-term cytotoxic response of thermoplastic polyamide and conventional polymethyle metacrylate (PMMA) denture base materials. Materials and ethods. Twenty discs were prepared for each polyamide, heat and cold cured PMMA denture base resins (totally 60) and divided into four sub-groups (n = 5). Cytotoxicity was assessed with the direct cell contact method using cell viability and neutral red (NR) uptake assay. Each sub-group was tested at initial and after being aged for 24 h, 1 week and 8 weeks with artificial saliva according to ISO 10993 standards. Results. There were no significantly difference among the materials and control groups after initial, 24 h and 1 week testing. In 24 h testing, only Deflex was more toxic according to the Control group (p < 0.05). After 8 weeks of aging with artificial saliva, all materials were significantly cytotoxic when compared to the control group. QC20 was more toxic than Deflex and SC Cold Cure (p < 0.05). There were significant differences between the 8 week aging group and the initial, 24 h and 1 week testing for all materials (p < 0.05). Conclusions. Cytotoxicity of all tested denture base materials increased significantly after the long-term aging. Therefore, long-term aging may be useful to determine a dental material's toxicity. Polyamide denture base material had a similar toxicity profile with conventional heat- and cold-cured PMMA.

Uzun IH; Tatar A; Hacimuftuoglu A; Saruhan F; Bayindir F

2013-09-01

229

Análise do desenvolvimento morfológico da blenda polimérica PBT/ABS durante as etapas de mistura por extrusão e moldagem por injeção/ Analysis of the morphological development of PBT/ABS blends during the extrusion and injection molding processes  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O enfoque principal deste trabalho foi observar o desenvolvimento da morfologia de fases da blenda binária PBT/ABS e desta blenda compatibilizada pela adição de um copolímero acrílico reativo, durante a etapa de mistura por extrusão e de moldagem por injeção. A evolução da morfologia das blendas, durante a etapa de mistura, foi analisada através do uso de amostras coletadas de uma extrusora de rosca dupla co-rotacional, com acessório especialmente projetado pa (more) ra coleta in line. A morfologia observada nas amostras obtidas por injeção foi realizada utilizando amostras retiradas de corpos de prova moldados. As amostras obtidas por extrusão e por moldagem por injeção foram posteriormente preparadas através de crio-ultramicrotomia e observadas através de microscopia eletrônica de transmissão (TEM). Uma "Função Dispersão" foi desenvolvida neste trabalho para comparar as diversas morfologias sob diferentes condições de processamento e de compatibilização. A adição de compatibilizante favorece a formação de uma morfologia de domínios de ABS dispersos em PBT, ao longo do canhão da extrusora, e previne satisfatoriamente o fenômeno de coalescência destes domínios durante o processo de moldagem por injeção. A função dispersão foi utilizada principalmente para mostrar a tendência da evolução morfológica e mostrou um bom desempenho para tal. Abstract in english The aim of this work was to observe the development of the phase morphology of the PBT/ABS blends during their extrusion mixing and injection molding steps. The evolution of the blend morphology during the mixing stage was analyzed using a specially designed co-rotational twin-screw extruder with a collecting device located along the barrel. Blend samples were collected in-line along the length of the extruder barrel during the blending process. Blend morphology was also (more) observed from specimens molded through injection molding. All the samples were observed by transmission electron microscopy (TEM). They were prepared by cryo-ultramicrotomy and the rubbery phase of the ABS contained in the blends was stained with osmium tetroxide (OsO4). A special function was established and is proposed to analyze the blend morphology trends through image analysis. In binary blends, the ABS phase showed better dispersion after the mixture passed through the extruder die. However, a coalescence phenomenon was observed during the next molding step. Compatibilized PBT/ABS blends showed better dispersion than binary blends, even after injection molding. The special function used to quantify the dispersion throughout the mixing and molding steps showed an excellent performance.

Ito, Edson N.; Pessan, Luiz A.; Hage Jr., Elias; Covas, José A.

2004-06-01

230

Análise do desenvolvimento morfológico da blenda polimérica PBT/ABS durante as etapas de mistura por extrusão e moldagem por injeção Analysis of the morphological development of PBT/ABS blends during the extrusion and injection molding processes  

Directory of Open Access Journals (Sweden)

Full Text Available O enfoque principal deste trabalho foi observar o desenvolvimento da morfologia de fases da blenda binária PBT/ABS e desta blenda compatibilizada pela adição de um copolímero acrílico reativo, durante a etapa de mistura por extrusão e de moldagem por injeção. A evolução da morfologia das blendas, durante a etapa de mistura, foi analisada através do uso de amostras coletadas de uma extrusora de rosca dupla co-rotacional, com acessório especialmente projetado para coleta in line. A morfologia observada nas amostras obtidas por injeção foi realizada utilizando amostras retiradas de corpos de prova moldados. As amostras obtidas por extrusão e por moldagem por injeção foram posteriormente preparadas através de crio-ultramicrotomia e observadas através de microscopia eletrônica de transmissão (TEM). Uma "Função Dispersão" foi desenvolvida neste trabalho para comparar as diversas morfologias sob diferentes condições de processamento e de compatibilização. A adição de compatibilizante favorece a formação de uma morfologia de domínios de ABS dispersos em PBT, ao longo do canhão da extrusora, e previne satisfatoriamente o fenômeno de coalescência destes domínios durante o processo de moldagem por injeção. A função dispersão foi utilizada principalmente para mostrar a tendência da evolução morfológica e mostrou um bom desempenho para tal.The aim of this work was to observe the development of the phase morphology of the PBT/ABS blends during their extrusion mixing and injection molding steps. The evolution of the blend morphology during the mixing stage was analyzed using a specially designed co-rotational twin-screw extruder with a collecting device located along the barrel. Blend samples were collected in-line along the length of the extruder barrel during the blending process. Blend morphology was also observed from specimens molded through injection molding. All the samples were observed by transmission electron microscopy (TEM). They were prepared by cryo-ultramicrotomy and the rubbery phase of the ABS contained in the blends was stained with osmium tetroxide (OsO4). A special function was established and is proposed to analyze the blend morphology trends through image analysis. In binary blends, the ABS phase showed better dispersion after the mixture passed through the extruder die. However, a coalescence phenomenon was observed during the next molding step. Compatibilized PBT/ABS blends showed better dispersion than binary blends, even after injection molding. The special function used to quantify the dispersion throughout the mixing and molding steps showed an excellent performance.

Edson N. Ito; Luiz A. Pessan; Elias Hage Jr.; José A. Covas

2004-01-01

231

THERMOPLASTIC RESIN COMPOSITION CONTAINING THERMOPLASTIC POLYMER CONTAINING ALICYCLIC GROUP AND MOLDED OBJECT  

UK PubMed Central (United Kingdom)

A thermoplastic resin composition (molding material) in which the problem that thermoplastic resins such as hydrogenated styrene polymers suffer a decrease in molecular weight upon melt molding and hence come to be mechanically brittle, is mitigated and which does not develop craze spots even when used in a high-temperature high-humidity atmosphere; and a substrate for optical recording media which comprises the composition. The thermoplastic resin composition comprises a thermoplastic polymer containing alicyclic groups and an addition-type stabilizer which can react by addition reaction with a free radical resulting from cleavage of the thermoplastic polymer.

YAMAURA MICHIO; KIDO NOBUAKI; MATSUMURA SHUNICHI; IWATA KAORU; HASHIDZUME KIYONARI; KOHNO KAZUTERU

232

Crystallization kinetics and morphology of PBT/MMT and PTT/MMT nanocomposites during injection molding;Cinetica de cristalizacao e morfologia de nanocompositos de PBT/MMT e PTT/MMT durante a moldagem por injecao  

Energy Technology Data Exchange (ETDEWEB)

This work had as main objective to study the crystallization of nanocomposites of poly(butylene terephthalate) (PBT) and poly(trimethylene terephthalate) (PTT) with a montmorillonite nanoclay (MMT) using an on-line optical monitoring system during the injection molding and to characterize the morphologies of the injection samples by polarized light optical microscopy (PLOM), wide angle X-ray diffraction (WAXS) and differential scanning calorimetry (DSC). The optical system allowed to analyze the crystallization process by the changes of the optical properties during the solidification of the materials. It was concluded that the MMT lamellae accelerated the overall crystallization of the polymers. By PLOM, it was observed that the nanoclay caused qualitative changes on the morphology of the PTT (polymer with slow crystallization kinetics). The crystallinity indexes were not affected by the addition of the MMT; however, by WAXS it was shown that the nanocomposites had a higher orientation degree. (author)

Favaro, Marcia M.; Branciforti, Marcia C.; Bretas, Rosario E.S., E-mail: mmfavaro@gmail.co [Universidade Federal de Sao Carlos (DEM/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais

2009-07-01

233

Thermoplastic composite bipolar plates for polymer electrolyte membrane fuel cells (PEMFC). Paper no. IGEC-1-089  

International Nuclear Information System (INIS)

Polymer electrolyte membrane fuel cells (PEMFC) are one significant component of the Hydrogen Economy. In order to make fuel cells economically feasible, processing and material cost need to be reduced. This reduction extends to the cost associated with bipolar plates. In an effort to produce functional bipolar plates at a competitive cost thermoplastic composite materials were extruded and injection molded, combining commercial materials such as polypropylene, carbon fiber, Vulcan carbon black, and acetylene carbon black. Two trials were executed. Trial 1 is a twenty sample experimental design and Trial 2 consists of different filler loadings with filler ratio 1:1:1. Thermal gravimetric analysis (TGA) was used to determine the actual filler loading following processing. Two methods of measuring electrical conductivity were investigated for Trial 1. Using method 1 a filler loading of 35 wt% and filler ratio of 1:1:1 reveals the best conductivity of 155 S/m. Method 2 has a maximum conductivity of 38 S/m and is achieved with a 32 wt% of only Vulcan carbon black. In Trial 2 a significant portion of the percolation curve for the filler ratio 1:1:1 is obtained. (author)

2005-01-01

234

Dynamically cured thermoplastic olefin polymers  

Energy Technology Data Exchange (ETDEWEB)

A thermoplastic composition is described comprising a polyolefin resin, a first rubber component selected from the group consisting of polyisobutylene, and ethylene propylene copolymer (EPM) and EPDM and a second rubber component selected from the group consisting of halogenated butyl rubber and polychoroprene, the second rubber component being cured utilizing a curative other than a peroxide, which is a vulcanizing agent for the second rubber but not for the first rubber, the second rubber being cured to a fully vulcanized state by dynamic vulcanization in the presence of the polyolefin resin and first rubber compound.

Hazelton, D.R.; Puydak, R.C.; Booth, D.A.

1986-08-19

235

Thermoplastic Elastomer Infill Synthetic Turf  

Directory of Open Access Journals (Sweden)

Full Text Available Synthetic – turf or Astroturf, is a grass-like man-made surface manufactured from synthetic polymers. It is most used for sports field and in residential area where natural grass is difficult to grow. Synthetic turf consist three basic components – grass filaments, Infill and backing. Grass filaments require softness and impact strength. Through several generations, grass filaments developed from initially nylon, polypropylene and now from polyethylene. Crumb rubber is used as infill material which contains toxic chemicals present in tyre. Some of the drawbacks of these materials can be solved by modifications in materials like by introduction of TPE –thermoplastic elastomer, which has been presented in this paper.

BHAKTI D.PATEL; PROF. RUPANDE N.DESAI

2013-01-01

236

USE OF THERMOPLASTIC ELASTOMERS IN FLOOR COVERING FOR ANIMAL HOUSING  

UK PubMed Central (United Kingdom)

The present invention relates to use of a thermoplastic elastomer in floor covering for industrial animal housing of cattle. The invention further relates to a thermoplastic elastomer in floor covering comprising one or more layers whereby preferably at least one layer is a dynamically vulcanized thermoplastic elastomer. The thermoplastic elastomer comprises a thermoplastic polymer and an elastomer. The elastomer is chosen from EPM, EPDM or SEBS and is preferably dynamically vulcanized. The thermoplastic polymer is preferably a polyolefine for example polypropylene. The use of a thermoplastic elastomer comprising a thermoplastic polymer and an elastomer shows improved fatigue properties and an improved resistance against corrosion tension. This means an improved chemical resistance and an improved deformation resistance. Another advantage is that the thermoplastic elastomer comprising the thermoplastic polymer and the elastomer leads to an improved abrasion resistance, which is an important property in animal housing as it prevents the animals from slipping of the floor coverings.

MAAREN VAN Martinus

237

Thermoplastic film prevents proppant flowback  

Energy Technology Data Exchange (ETDEWEB)

Thermoplastic film added to proppants is effective and economical for preventing proppant flowback after an hydraulic fracturing treatment. Most other methods, such as resin-coated proppant and fiber, for controlling proppant flowback have drawbacks that added to treatment costs by requiring long downtime, costly additives, or frequent equipment replacement. Thermoplastic film does not react chemically with fracturing fluids. After the proppant is placed in the fracture, the film strips intertwine with the proppant grains or at higher temperatures, the strips become adhesive and shrink forming consolidated clusters that hold open the newly created fractures and prevent proppant from flowing back. The low cost of the film means that the strips can be used throughout the fracturing job or in selected stages. The strips are compatible with fracturing fluid chemistry, including breakers and crosslinkers, and can be used in wells with a wide range of bottom hole temperatures. The end result is a well that can be brought back on-line in a short time with little proppant flowback. This paper reviews the cost benefits and performance of these proppants.

Nguyen, P.D.; Weaver, J.D.; Parker, M.A.; King, D.G. [Halliburton Energy Services, Duncan, OK (United States)

1996-02-05

238

Joining of thermoplastic substrates by microwaves  

Energy Technology Data Exchange (ETDEWEB)

A method for joining two or more items having surfaces of thermoplastic material includes the steps of depositing an electrically-conductive material upon the thermoplastic surface of at least one of the items, and then placing the other of the two items adjacent the one item so that the deposited material is in intimate contact with the surfaces of both the one and the other items. The deposited material and the thermoplastic surfaces contacted thereby are then exposed to microwave radiation so that the thermoplastic surfaces in contact with the deposited material melt, and then pressure is applied to the two items so that the melted thermoplastic surfaces fuse to one another. Upon discontinuance of the exposure to the microwave energy, and after permitting the thermoplastic surfaces to cool from the melted condition, the two items are joined together by the fused thermoplastic surfaces. The deposited material has a thickness which is preferably no greater than a skin depth, .delta..sub.s, which is related to the frequency of the microwave radiation and characteristics of the deposited material in accordance with an equation.

Paulauskas, Felix L. (Oak Ridge, TN); Meek, Thomas T. (Knoxville, TN)

1997-01-01

239

MODIFICATION OF JACK PINE TMP LONG FIBERS BY ALKALINE PEROXIDE – PART 1. CHEMICAL CHARACTERISTICS OF FIBERS AND SPENT LIQUOR  

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of this work was to improve the quality of jack pine TMP long fibers, particularly with respect to the strength properties, by alkaline peroxide treatment. This paper reports the chemical characteristics of the treated long fibers and the spent liquors originating from various treatments. It was observed that, in comparison with hydrogen peroxide, the alkalinity of the treatment solutions had a greater influence on most fibre characteristics and spent liquor properties.

Ying Han; Kwei-Nam Law; Robert Lanouette

2008-01-01

240

HYDROFLUOROPROPENE BLOWING AGENTS FOR THERMOPLASTICS  

UK PubMed Central (United Kingdom)

The present invention relates to blowing agent compositions comprising at least one hydrochlorofluoroolefin (HCFO) used in the preparation of foamable thermoplastic compositions. The HCFOs of the present invention include, but are not limited to, 1-chloro-3, 3,3-trifluoropropene (HCFO-1233zd), particularly the trans-isomer, 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), dichloro-fluorinated propenes, and mixtures thereof. The blowing agent compositions of the present invention are used with coblowing agents including carbon dioxide, atmospheric gases, hydrofluorocarbons (HFC), hydrofluoroolefins (HFO), alkanes, hydrofluoroethers (HFE), and mixtures thereof. Preferred HFCs used as coblowing agents in the present invention include, but are not limited to, 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1-difluoroethane (HFC-152a), 1,1,1-trifluoroethane (HFC-143a), pentafluorethane (HFC-125), difluoromethane (HFC-32). The blowing agent compositions are useful in the production of low density insulating foams with improved k-factor.

VAN HORN BRETT L; ELSHEIKH MAHER Y; CHEN BENJAMIN BIN; BONNET PHILIPPE

 
 
 
 
241

Reactive Plasticizers for High Temperature Quinoxaline Thermoplastics.  

Science.gov (United States)

This report is concerned with a novel approach to the processing of high temperature thermoplastics. A series of bis(ethynylquinoxaline) monomers were prepared to demonstrate the feasibility of using reactive plasticizers in the processing of polyphenylqu...

R. F. Kovar G. F. L. Ehlers F. E. Arnold

1976-01-01

242

Interlaminar fracture toughness of thermoplastic composites  

Energy Technology Data Exchange (ETDEWEB)

Edge delamination tension and double cantilever beam tests were used to characterize the interlaminar fracture toughness of continuous graphite-fiber composites made from experimental thermoplastic polyimides and a model thermoplastic. Residual thermal stresses, known to be significant in materials processed at high temperatures, were included in the edge delamination calculations. In the model thermoplastic system (polycarbonate matrix), surface properties of the graphite fiber were shown to be significant. Critical strain energy release rates for two different fibers having similar nominal tensile properties differed by 30 to 60%. The reason for the difference is not clear. Interlaminar toughness values for the thermoplastic polyimide composites (LARC-TPI and polyimidesulfone) were 3 to 4 in-lb/sq in. Scanning electron micrographs of the EDT fracture surfaces suggest poor fiber/matrix bonding. Residual thermal stresses account for up to 32% of the strain energy release in composites made from these high-temperature resins.

Hinkley, J.A.; Johnston, N.J.; Obrien, T.K.

1988-02-01

243

Implementation of New Process Models for Tailored Polymer Composite Structures into Processing Software Packages  

Energy Technology Data Exchange (ETDEWEB)

This report describes the work conducted under the Cooperative Research and Development Agreement (CRADA) (Nr. 260) between the Pacific Northwest National Laboratory (PNNL) and Autodesk, Inc. to develop and implement process models for injection-molded long-fiber thermoplastics (LFTs) in processing software packages. The structure of this report is organized as follows. After the Introduction Section (Section 1), Section 2 summarizes the current fiber orientation models developed for injection-molded short-fiber thermoplastics (SFTs). Section 3 provides an assessment of these models to determine their capabilities and limitations, and the developments needed for injection-molded LFTs. Section 4 then focuses on the development of a new fiber orientation model for LFTs. This model is termed the anisotropic rotary diffusion - reduced strain closure (ARD-RSC) model as it explores the concept of anisotropic rotary diffusion to capture the fiber-fiber interaction in long-fiber suspensions and uses the reduced strain closure method of Wang et al. to slow down the orientation kinetics in concentrated suspensions. In contrast to fiber orientation modeling, before this project, no standard model was developed to predict the fiber length distribution in molded fiber composites. Section 5 is therefore devoted to the development of a fiber length attrition model in the mold. Sections 6 and 7 address the implementations of the models in AMI, and the conclusions drawn from this work is presented in Section 8.

Nguyen, Ba Nghiep; Jin, Xiaoshi; Wang, Jin; Phelps, Jay; Tucker III, Charles L.; Kunc, Vlastimil; Bapanapalli, Satish K.; Smith, Mark T.

2010-02-23

244

Implementation of New Process Models for Tailored Polymer Composite Structures into Processing Software Packages  

International Nuclear Information System (INIS)

This report describes the work conducted under the Cooperative Research and Development Agreement (CRADA) (Nr. 260) between the Pacific Northwest National Laboratory (PNNL) and Autodesk, Inc. to develop and implement process models for injection-molded long-fiber thermoplastics (LFTs) in processing software packages. The structure of this report is organized as follows. After the Introduction Section (Section 1), Section 2 summarizes the current fiber orientation models developed for injection-molded short-fiber thermoplastics (SFTs). Section 3 provides an assessment of these models to determine their capabilities and limitations, and the developments needed for injection-molded LFTs. Section 4 then focuses on the development of a new fiber orientation model for LFTs. This model is termed the anisotropic rotary diffusion - reduced strain closure (ARD-RSC) model as it explores the concept of anisotropic rotary diffusion to capture the fiber-fiber interaction in long-fiber suspensions and uses the reduced strain closure method of Wang et al. to slow down the orientation kinetics in concentrated suspensions. In contrast to fiber orientation modeling, before this project, no standard model was developed to predict the fiber length distribution in molded fiber composites. Section 5 is therefore devoted to the development of a fiber length attrition model in the mold. Sections 6 and 7 address the implementations of the models in AMI, and the conclusions drawn from this work is presented in Section 8.

2010-01-01

245

Comparison between Palm Oil Derivative and Commercial Thermo-Plastic Binder System on the Properties of the Stainless Steel 316L Sintered Parts  

Science.gov (United States)

Binder system is one of the most important criteria for the powder injection molding (PIM) process. Failure in the selection of the binder system will affect on the final properties of the sintered parts. The objectives of this studied is to develop a novel binder system based on the local natural resources and environmental friendly binder system from palm oil derivative which is easily available and cheap in our country of Malaysia. The novel binder that has been developed will be replaced the commercial thermo-plastic binder system or as an alternative binder system. The results show that the physical and mechanical properties of the final sintered parts fulfill the Metal Powder Industries Federation (MPIF) standard 35 for PIM parts. The biocompatibility test using cell osteosarcoma (MG63) and vero fibroblastic also shows that the cell was successfully growth on the sintered stainless steel 316L parts indicate that the novel binder was not toxic. Therefore, the novel binder system based on palm oil derivative that has been developed as a binder system fulfills the important criteria for the binder system in PIM process.

Ibrahim, R.; Azmirruddin, M.; Wei, G. C.; Fong, L. K.; Abdullah, N. I.; Omar, K.; Muhamad, M.; Muhamad, S.

2010-03-01

246

Reinforcing thermoplastics with hydrogen bonding bridged inorganics  

International Nuclear Information System (INIS)

A new reinforcing strategy for thermoplastics via hydrogen bonding bridged inorganics in the matrix was proposed. The hydrogen bonds could be formed in thermoplastics matrices with the incorporation of a little organics containing hydrogen bonding functionalities. Isotactic polypropylene (PP), polyamide 6 (PA 6), and high density polyethylene (HDPE), together with specific inorganics and organics were utilized to verify the effectiveness of the strategy. The investigations suggest that the hydrogen bonding bridged inorganics led to substantially increased flexural properties. The results of attenuated total refraction Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectra (XPS) indicate the formation of hydrogen bonding among the inorganics and organics in the composites.

2010-01-15

247

Avaliação do comportamento térmico por DSC na região da pele e do núcleo de amostras injetadas de nanocompósitos de poliamida 6/argila organofílica Polyamide 6/organoclay nanocomposites: evaluation of thermal behavior of injection molded samples by DSC  

Directory of Open Access Journals (Sweden)

Full Text Available Nanocompósitos de poliamida 6/argila organofílica foram preparados pelo método de intercalação por fusão. A argila foi tratada com o sal quaternário de amônio (Cetremide) visando-se à obtenção da argila organofílica (OMMT). Esta foi caracterizada por fluorescência de raio X (FRX), Espectroscopia no Infravermelho (FTIR) e Difração de Raio X (DRX). Os resultados dessas análises evidenciaram incorporação do sal entre as camadas da argila, tornando-a organofílica. Os nanocompósitos foram obtidos em extrusora de rosca dupla corrotacional, com 3% em peso de argila, e estes foram posteriormente injetados. A caracterização dos nanocompósitos por DRX mostrou uma estrutura esfoliada e/ou parcialmente esfoliada. As análises por Calorimetria Exploratória Diferencial (DSC) foram realizadas nas regiões da pele (superfície) e do núcleo (centro) dos corpos de prova e, mostraram as fases cristalinas ? e ? na pele e apenas a fase ? no núcleo e que o grau de cristalinidade na pele foi menor do que no núcleo.Polyamide 6/organoclay nanocomposites were prepared using the melt intercalation technique. The clay was treated with a quaternary ammonium salt (Cetremide) to obtain the organoclay (OMMT), which was characterized with X ray fluorescence (XRF), Infrared Spectroscopy (FTIR) and X ray diffraction (XRD). The results of these analyses showed the incorporation of the salt in the clay structure, confirming the organophilization. The nanocomposites were obtained in a co-rotational twin screw extruder with 3 wt. (%) of clay, and then the pellets were injection molded. The characterization by XRD of the nanocomposites showed an exfoliated and/or partially exfoliated structure. The analysis by DSC were made in the skin and core regions of the samples, showing the ? and ?-crystalline forms in the skin and only the ?-form in the core region. The degree of crystallinity in the skin was lower than in the core.

Renê A. da Paz; Amanda M. D. Leite; Edcleide M. Araújo; Tomas J. A. Melo; Luiz A. Pessan

2010-01-01

248

Avaliação do comportamento térmico por DSC na região da pele e do núcleo de amostras injetadas de nanocompósitos de poliamida 6/argila organofílica/ Polyamide 6/organoclay nanocomposites: evaluation of thermal behavior of injection molded samples by DSC  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Nanocompósitos de poliamida 6/argila organofílica foram preparados pelo método de intercalação por fusão. A argila foi tratada com o sal quaternário de amônio (Cetremide) visando-se à obtenção da argila organofílica (OMMT). Esta foi caracterizada por fluorescência de raio X (FRX), Espectroscopia no Infravermelho (FTIR) e Difração de Raio X (DRX). Os resultados dessas análises evidenciaram incorporação do sal entre as camadas da argila, tornando-a organof (more) ílica. Os nanocompósitos foram obtidos em extrusora de rosca dupla corrotacional, com 3% em peso de argila, e estes foram posteriormente injetados. A caracterização dos nanocompósitos por DRX mostrou uma estrutura esfoliada e/ou parcialmente esfoliada. As análises por Calorimetria Exploratória Diferencial (DSC) foram realizadas nas regiões da pele (superfície) e do núcleo (centro) dos corpos de prova e, mostraram as fases cristalinas ? e ? na pele e apenas a fase ? no núcleo e que o grau de cristalinidade na pele foi menor do que no núcleo. Abstract in english Polyamide 6/organoclay nanocomposites were prepared using the melt intercalation technique. The clay was treated with a quaternary ammonium salt (Cetremide) to obtain the organoclay (OMMT), which was characterized with X ray fluorescence (XRF), Infrared Spectroscopy (FTIR) and X ray diffraction (XRD). The results of these analyses showed the incorporation of the salt in the clay structure, confirming the organophilization. The nanocomposites were obtained in a co-rotation (more) al twin screw extruder with 3 wt. (%) of clay, and then the pellets were injection molded. The characterization by XRD of the nanocomposites showed an exfoliated and/or partially exfoliated structure. The analysis by DSC were made in the skin and core regions of the samples, showing the ? and ?-crystalline forms in the skin and only the ?-form in the core region. The degree of crystallinity in the skin was lower than in the core.

Paz, Renê A. da; Leite, Amanda M. D.; Araújo, Edcleide M.; Melo, Tomas J. A.; Pessan, Luiz A.

2010-01-01

249

Synthesis of Energetic Polyester Thermoplastic Homopolymers and Energetic Thermoplastic Elastomers Formed Therefrom.  

Science.gov (United States)

For many years, DREV has been involved in the synthesis of energetic thermoplastic elastomers (ETPEs) based on linear glycidyl azide polymer (GAP). These polymers are physically-crosslinked rubbery materials that can be melted, dissolved or recycled and c...

G. Ampierman S. Brochu M. Desjardins

2001-01-01

250

Thermoplastic film camera for holographic recording  

International Nuclear Information System (INIS)

The design thermoplastic-film recording camera and its performance for holography of extended objects are reported. Special corona geometry and accurate control of development heat by constant current heating and high resolution measurement of the develop temperature make easy recording of reproducible, large aperture holograms possible. The experimental results give the transfer characteristics, the diffraction efficiency characteristics and the spatial frequency response. (orig.).

1982-03-22

251

Investigation of physical properties of thermoplastic polyimides  

Energy Technology Data Exchange (ETDEWEB)

Thermoplastic polyimides are a class of promising high temperature polymers for aerospace applications. NASA-developed LARC-TPI is a prominent member of this family of polymers. Its physical characteristics have been measured as a function of its curing schedule. The results and their possible interpretations are discussed.

Singh, J.J.; Stoakley, D.M.

1987-12-01

252

Apparatus for thermoforming thermoplastic sheet materials  

Energy Technology Data Exchange (ETDEWEB)

The present invention relates to an improved plug or tool for use in the production of shaped articles from thermoplastic sheet materials. An important feature of the present invention is that the tool or plug comprises a body portion which incorporates one or more inserts which possess a thermal conductivity different from the thermal conductivity of the body portion.

Bullock, L.W.; Kovacs, F.; Vlahek, J.

1985-02-19

253

Glass transition temperature of thermoplastic starches  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thermoplastic starch was produced by mixing potato starch and glycerol in a single screw extruder. The glass transition temperatures of the materials obtained were measured by differential scanning calorimetry (DSC). Both the influence of extruder parameters and material parameters, such as moisture...

M. Mitrus

254

Thermoplastic Composite Materials for Aerospace Applications  

Science.gov (United States)

Mechanical and thermo-physical properties of composites materials with thermoplastic matrix (PEEK/IM7, TPI/IM7 and PPS/IM7) used for aerospace applications have been analyzed as function of two different process techniques: compression molding and fiber placement process ``hot gas assisted.''

Casula, G.; Lenzi, F.; Vitiello, C.

2008-08-01

255

THERMOPLASTIC ELASTOMERS EXHIBITING SUPERIOR ABRASION RESISTANCE PROPERTIES  

UK PubMed Central (United Kingdom)

A blend of thermoplastic polyester elastomer, hydrogenated styrenic block copolymer, and high styrene content styrenic block copolymer is disclosed which has good processability and more effective abrasion resistance than the blend using polystyrene in place of the high styrene content styrenic block copolymer.

QIAN GUOQIANG; VENKATASWAMY KRISHNA

256

IMAGE ANALYSIS DEDICATED TO POLYMER INJECTION MOLDING  

Directory of Open Access Journals (Sweden)

Full Text Available This work follows the general framework of polymer injection moulding simulation whose objectives are the mastering of the injection moulding process. The models of numerical simulation make it possible to predict the propagation of the molten polymer during the filling phase from the positioning of one point of injection or more. The objective of this paper is to propose a particular way to optimize the geometry of mold cavity in accordance with physical laws. A direct correlation is pointed out between geometric parameters issued from skeleton transformation and Hausdorff's distance and results provided by implementation of a classical model based on the Hele-Shaw equations which are currently used in the main computer codes of polymer injection.

David Garcia; Guy Courbebaisse; Michel Jourlin

2001-01-01

257

Injection molding of power-law polymer  

Science.gov (United States)

A polymer in injected with a constant pressure gradient between two parallel plates. The progression of the polymer front is modeled for a power law fluid (typical of a polymer) and compared to results for a Newtonian fluid.

Krane, Matthew J.

2008-10-25

258

Efeito do processamento em misturas de alumina/ligantes orgânicos usadas na moldagem por injeção em baixa pressão Effect of processing variables in alumina/organic binders mixtures used in low-pressure injection molding  

Directory of Open Access Journals (Sweden)

Full Text Available A moldagem por injeção em baixa pressão (MIBP) é uma técnica que já vem sendo empregada na produção de peças cerâmicas com formas e geometrias complexas. A homogeneidade da mistura de ligantes orgânicos e pós cerâmicos é um fator determinante que deve ser controlado para minimizar a formação de imperfeições no processamento de feedstocks para MIBP. Defeitos típicos de processamento por MIBP, como bolhas de ar e aglomerados, geram gradientes de densidade nas misturas que, após conformação, possuem poucas possibilidades de remoção. Essas imperfeições comprometem o desempenho dos produtos obtidos por essa técnica. Este trabalho está focado na avaliação dessas heterogeneidades e como elas podem ser correlacionadas com a variação da densidade aparente e com o comportamento reológico dessas misturas. Para tanto, aluminas submicrométricas, como recebida e desaglomerada, foram adicionadas a uma mistura fundida de ligantes a base de parafinas, ceras e aditivos e processada em dois tipos diferentes de misturadores, com e sem o auxílio de vácuo. Foi observada a presença de aglomerados existentes na alumina como recebida, possivelmente gerados durante a etapa de calcinação. Também foi observado que o tipo de misturador e a aplicação ou não de vácuo durante a etapa final do processamento têm grande influência no tempo de mistura necessário para reduzir a viscosidade do feedstock para a injeção.The low-pressure injection molding (LPIM) is a technique already being used in the production of ceramic parts with complex shapes and geometries. The homogeneity of the mixture of organic binder and ceramic powder is a determining factor which must be controlled to minimize defects formation while feedstock processing to LPIM. Typical defects of LPIM processing, such as air bubbles and agglomerates, generate density gradients in the mixtures, which, after shaping, have little possibility of removal. These imperfections compromise the performance of the products obtained by this technique. This work is focused on the evaluation of these inhomogeneities and how they can be correlated with density variation and the rheological behavior of these mixtures. Therefore, submicrometer aluminas, as received and deagglomerated, were added to a molten mixture of paraffin based binders, waxes and additives and processed in two different mixers, with and without vacuum. The presence of alumina agglomerates was observed in the powder as received, possibly generated during the calcination step. It was also observed that the type of mixer and vacuum application or not during the final processing step, has a major influence on the mixing time required to reduce the viscosity of the feedstock for injection.

P . A. Ourique; A. Susin Neto; S. G. Echeverrigaray; R. C. D. Cruz; J. E. Zorzi

2013-01-01

259

Efeito do processamento em misturas de alumina/ligantes orgânicos usadas na moldagem por injeção em baixa pressão/ Effect of processing variables in alumina/organic binders mixtures used in low-pressure injection molding  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A moldagem por injeção em baixa pressão (MIBP) é uma técnica que já vem sendo empregada na produção de peças cerâmicas com formas e geometrias complexas. A homogeneidade da mistura de ligantes orgânicos e pós cerâmicos é um fator determinante que deve ser controlado para minimizar a formação de imperfeições no processamento de feedstocks para MIBP. Defeitos típicos de processamento por MIBP, como bolhas de ar e aglomerados, geram gradientes de densidade (more) nas misturas que, após conformação, possuem poucas possibilidades de remoção. Essas imperfeições comprometem o desempenho dos produtos obtidos por essa técnica. Este trabalho está focado na avaliação dessas heterogeneidades e como elas podem ser correlacionadas com a variação da densidade aparente e com o comportamento reológico dessas misturas. Para tanto, aluminas submicrométricas, como recebida e desaglomerada, foram adicionadas a uma mistura fundida de ligantes a base de parafinas, ceras e aditivos e processada em dois tipos diferentes de misturadores, com e sem o auxílio de vácuo. Foi observada a presença de aglomerados existentes na alumina como recebida, possivelmente gerados durante a etapa de calcinação. Também foi observado que o tipo de misturador e a aplicação ou não de vácuo durante a etapa final do processamento têm grande influência no tempo de mistura necessário para reduzir a viscosidade do feedstock para a injeção. Abstract in english The low-pressure injection molding (LPIM) is a technique already being used in the production of ceramic parts with complex shapes and geometries. The homogeneity of the mixture of organic binder and ceramic powder is a determining factor which must be controlled to minimize defects formation while feedstock processing to LPIM. Typical defects of LPIM processing, such as air bubbles and agglomerates, generate density gradients in the mixtures, which, after shaping, have l (more) ittle possibility of removal. These imperfections compromise the performance of the products obtained by this technique. This work is focused on the evaluation of these inhomogeneities and how they can be correlated with density variation and the rheological behavior of these mixtures. Therefore, submicrometer aluminas, as received and deagglomerated, were added to a molten mixture of paraffin based binders, waxes and additives and processed in two different mixers, with and without vacuum. The presence of alumina agglomerates was observed in the powder as received, possibly generated during the calcination step. It was also observed that the type of mixer and vacuum application or not during the final processing step, has a major influence on the mixing time required to reduce the viscosity of the feedstock for injection.

Ourique, P . A.; Susin Neto, A.; Echeverrigaray, S. G.; Cruz, R. C. D.; Zorzi, J. E.

2013-03-01

260

Induced mutation of Egypt cotton variety and selection of long fiber cotton mutant by irradiation  

International Nuclear Information System (INIS)

In order to obtain long fiber cotton variety which would be adaptable to the ecological conditions of Yellow River Region, the mutation induction of Egypt cotton variety, Ashmouni, was carried out by ?-ray of 279 Gy in 1985. In M1 generation, serious radiation damage was shown in seed-lings, the death percentage of seedling was 63.3%. Two plants with early maturity were selected and their seeds were planted individually in 1986. The complex segregation appeared in M2 generation. The selection and domestication were carried out for several years and four stable mutant lines which included early maturity, dwarf plant, compact pattern, stranger bollbearing ability as well as upland cotton characters were obtained in 1991. The fiber length of these lines reached 33 ? 35 mm, and the mutants were adaptable to ecological condition in Shandong Province. The mutant line, 90197-1, whose growing period and plant height shorter than those of upland cotton cultivar, Zhong-mian No.12, has compact plant pattern, high bollbearing ability and ginning out turn of about 40%. Further yield test is required for these lines. The hereditary variability of the progeny in mutated Egypt cotton variety, preliminary cytological observation and the analysis of isoenzyme in mutants are also discussed.

1994-01-01

 
 
 
 
261

Effects of mechanical properties of thermoplastic materials on the initial force of thermoplastic appliances.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To measure the forces delivered by thermoplastic appliances made from three materials and investigate effects of mechanical properties, material thickness, and amount of activation on orthodontic forces. MATERIALS AND METHODS: Three thermoplastic materials, Duran (Scheu Dental), Erkodur (Erkodent Erich Kopp GmbH), and Hardcast (Scheu Dental), with two different thicknesses were selected. Values of elastic modulus and hardness were obtained from nanoindentation measurements at 28°C. A custom-fabricated system with a force sensor was employed to obtain measurements of in vitro force delivered by the thermoplastic appliances for 0.5-mm and 1.0-mm activation for bodily tooth movement. Experimental results were subjected to several statistical analyses. RESULTS: Hardcast had significantly lower elastic modulus and hardness than Duran and Erkodur, whose properties were not significantly different. Appliances fabricated from thicker material (0.75 mm or 0.8 mm) always produced significantly greater force than those fabricated from thinner material (0.4 mm or 0.5 mm). Appliances with 1.0-mm activation produced significantly lower force than those with 0.5-mm activation, except for 0.4-mm thick Hardcast appliances. A strong correlation was found between mechanical properties of the thermoplastic materials and force produced by the appliances. CONCLUSIONS: Orthodontic forces delivered by thermoplastic appliances depend on the material, thickness, and amount of activation. Mechanical properties of the polymers obtained by nanoindentation testing are predictive of force delivery by these appliances.

Kohda N; Iijima M; Muguruma T; Brantley WA; Ahluwalia KS; Mizoguchi I

2013-05-01

262

The use of thermoplastic lined pipelines for aggressive hydrocarbon service  

Energy Technology Data Exchange (ETDEWEB)

This study is related to the use of thermoplastic liners to control corrosion of new and rehabilitated pipelines carrying aggressive hydrocarbon products. The aim is to investigate the technical and safety issues involved in introducing a thermoplastic liner into an existing carbon steel pipeline for aggressive hydrocarbon service at temperatures up to 150 C and internal pressures up to 34 MPa (5,000 psi). The principle objective is to provide design data for thermoplastic lined pipelines. The scope combines the use of liner insertion techniques with thermoplastic materials widely used in onshore pipelines and demonstrates the effectiveness of thermoplastic linings. The results indicate that thermoplastic liners can be used to control corrosion of pipelines in aggressive hydrocarbon environments.

Woodward, K.A.; Al-Hassan, T. [Health and Safety Executive, Merseyside (United Kingdom). Offshore Safety Div.

1996-12-31

263

Examination of injection moulded thermoplastic maize starch  

Directory of Open Access Journals (Sweden)

Full Text Available This paper focuses on the effect of the different injection moulding parameters and storing methods on injection moulded thermoplastic maize starch (TPS). The glycerol and water plasticized starch was processed in a twin screw extruder and then with an injection moulding machine to produce TPS dumbbell specimens. Different injection moulding set-ups and storing conditions were used to analyse the effects on the properties of thermoplastic starch. Investigated parameters were injection moulding pressure, holding pressure, and for the storage: storage at 50% relative humidity, and under ambient conditions. After processing the mechanical and shrinkage properties of the manufactured TPS were determined as a function of the ageing time. While conditioning, the characteristics of the TPS changed from a soft material to a rigid material. Although this main behaviour remained, the different injection moulding parameters changed the characteristics of TPS. Scanning electron microscope observations revealed the changes in the material on ageing.

2007-01-01

264

Thermoplastic retention appliances. A controversial clinical reality.  

Directory of Open Access Journals (Sweden)

Full Text Available AIM: The present article attempts to critically analyze the efficiency, advantages and disadvantages of thermoplastic appliances, which are widely used today to retain the outcome of an orthodontic treatment.METHOD: Collection and evaluation of original articles regarding the subject under investigation from PubMed and Cochrane Databases until January 2010.FINDINGS: Transparent appliances are the preferred appliances to retain the orthodontic treatment outcome both by patients and clinicians. They are efficient, esthetically pleasing, provide comfort and have low cost. Despite their tendency to develop open bite and unwanted occlusal contacts, the partial or continuous application and the duration of use don’t seem to comprise destabilizing elements of the treatment outcome compared to Hawley appliances.CONCLUSION: The efficiency combined with the advantages and disadvantages make the thermoplastic appliances an alternative choice to Hawley orthodontic appliances. However, evidence based research needs to establish the advantages of these retention appliances compared to other retention appliances.

Ioulia Ioannidou-Marathiotou

2011-01-01

265

LARC-TPI and new thermoplastic polyimides  

Energy Technology Data Exchange (ETDEWEB)

The LARC-TPI linear thermoplastic polyimide has been developed by NASA for high temperature adhesive applications in aerospace structures in the forms of varnish, films, powders, and prepregs. LARC-TPI improves adhesive processability and lowers glass transition temperature, while retaining mechanical, thermal and electrical properties inherent in the polyimides. It may be used as a structural adhesive for metals, composites, ceramics, and films. 8 references.

Yamaguchi, A.; Ohta, M.

1987-02-01

266

Glass transition temperature of thermoplastic starches  

Directory of Open Access Journals (Sweden)

Full Text Available Thermoplastic starch was produced by mixing potato starch and glycerol in a single screw extruder. The glass transition temperatures of the materials obtained were measured by differential scanning calorimetry (DSC). Both the influence of extruder parameters and material parameters, such as moisture and glycerol content and amyloses/amylopectine ratio were investigated. Repeated extrusion cycles affect the glass transition temperature only to a very small extent.

M. Mitrus

2005-01-01

267

Evolução da morfologia de fases de blendas PA6/AES em extrusora de dupla rosca e moldagem por injeção/ Evolution of phase morphology of PA6/AES blends during the twin screw extrusion and injection molding processes  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A evolução da morfologia de fases em blendas não reativas e reativas de poliamida-6 com copolímero de acrilonitrila/EPDM/estireno (AES) em uma extrusora de rosca dupla co-rotacional foi investigada. A evolução da morfologia de fases ao longo da extrusora de rosca dupla foi monitorada através da coleta de pequenas amostras em válvulas no barril da extrusora e caracterização por microscopia eletrônica de transmissão (MET). Foram utilizados como compatibilizantes (more) reativos os copolímeros metacrilato de metila-co-anidrido maleico (MMA-MA) e metacrilato de metila-co-metacrilato de glicidila (MMA-GMA). Os grupos anidrido maleico e epóxi nos copolímeros podem reagir com os grupos finais de cadeia da poliamida durante o processamento no estado fundido e melhorar a interação na interfase do sistema PA6/AES. A blenda PA6/AES não compatibilizada apresentou uma morfologia grosseira de fases onde a fase AES não está bem dispersa na matriz de PA6 devido à falta de interações adequadas entre os componentes da blenda. A adição do compatibilizante MMA-GMA não proporcionou boa dispersão de fases e não melhorou as propriedades mecânicas da blenda, provavelmente porque as possíveis reações no sistema são lentas e podem não ocorrer na extrusora. Por outro lado, a blenda compatibilizada com o copolímero MMA-MA apresentou uma excelente resistência ao impacto à temperatura ambiente e uma diminuição na temperatura de transição dúctil-frágil. As partículas de AES apresentam-se muito mais refinadas e sofrem uma redução significativa em seu tamanho já no início do processo de extrusão. A morfologia observada nas amostras injetadas apresentou uma boa correlação com as propriedades mecânicas obtidas. Abstract in english The evolution of phase morphology in non-reactive vs reactive blends with polyamide and ethylene-propylene-diene elastomer grafted with styrene-acrylonitrile copolymer (AES) in a co-rotating twin-screw extruder was investigated. The morphological evolution of these blends along a twin-screw extruder was monitored by quickly collecting small samples from the melt at specific extruder barrel locations and characterizing them with a transmission electron microscope (TEM). Th (more) e copolymers methyl methacrylate-co-maleic anhydride (MMA-MA) and methyl methacrylate-co-glycidyl methacrylate (MMA-GMA) were used as compatibilizing agents. The maleic anhydride and the epoxy groups of the copolymers can react with the polyamide end groups during melt processing and improve the interphase interaction in the PA6/AES system. The uncompatibilized blends showed a coarse phase morphology where the AES phase is not well dispersed in the PA6 matrix due to lack of adequate interaction between the components. The addition of MMA-GMA compatibilizer neither promoted good phase dispersion or improved the mechanical properties of the blends, probably because the possible reactions are very slow and may not occur inside the extruder. On the other hand, the addition of the MMA-MA copolymer promotes better impact strength and good phase dispersion in the blend. The AES particles undergo significant reduction in the first stages of the mixture inside the extruder. The morphology observed for the injection molded specimens was correlated with the mechanical properties.

Bassani, Adriane; Hage Jr, Elias; Pessan, Luiz A.; Machado, Ana V; Covas, José A.

2005-07-01

268

Evolução da morfologia de fases de blendas PA6/AES em extrusora de dupla rosca e moldagem por injeção Evolution of phase morphology of PA6/AES blends during the twin screw extrusion and injection molding processes  

Directory of Open Access Journals (Sweden)

Full Text Available A evolução da morfologia de fases em blendas não reativas e reativas de poliamida-6 com copolímero de acrilonitrila/EPDM/estireno (AES) em uma extrusora de rosca dupla co-rotacional foi investigada. A evolução da morfologia de fases ao longo da extrusora de rosca dupla foi monitorada através da coleta de pequenas amostras em válvulas no barril da extrusora e caracterização por microscopia eletrônica de transmissão (MET). Foram utilizados como compatibilizantes reativos os copolímeros metacrilato de metila-co-anidrido maleico (MMA-MA) e metacrilato de metila-co-metacrilato de glicidila (MMA-GMA). Os grupos anidrido maleico e epóxi nos copolímeros podem reagir com os grupos finais de cadeia da poliamida durante o processamento no estado fundido e melhorar a interação na interfase do sistema PA6/AES. A blenda PA6/AES não compatibilizada apresentou uma morfologia grosseira de fases onde a fase AES não está bem dispersa na matriz de PA6 devido à falta de interações adequadas entre os componentes da blenda. A adição do compatibilizante MMA-GMA não proporcionou boa dispersão de fases e não melhorou as propriedades mecânicas da blenda, provavelmente porque as possíveis reações no sistema são lentas e podem não ocorrer na extrusora. Por outro lado, a blenda compatibilizada com o copolímero MMA-MA apresentou uma excelente resistência ao impacto à temperatura ambiente e uma diminuição na temperatura de transição dúctil-frágil. As partículas de AES apresentam-se muito mais refinadas e sofrem uma redução significativa em seu tamanho já no início do processo de extrusão. A morfologia observada nas amostras injetadas apresentou uma boa correlação com as propriedades mecânicas obtidas.The evolution of phase morphology in non-reactive vs reactive blends with polyamide and ethylene-propylene-diene elastomer grafted with styrene-acrylonitrile copolymer (AES) in a co-rotating twin-screw extruder was investigated. The morphological evolution of these blends along a twin-screw extruder was monitored by quickly collecting small samples from the melt at specific extruder barrel locations and characterizing them with a transmission electron microscope (TEM). The copolymers methyl methacrylate-co-maleic anhydride (MMA-MA) and methyl methacrylate-co-glycidyl methacrylate (MMA-GMA) were used as compatibilizing agents. The maleic anhydride and the epoxy groups of the copolymers can react with the polyamide end groups during melt processing and improve the interphase interaction in the PA6/AES system. The uncompatibilized blends showed a coarse phase morphology where the AES phase is not well dispersed in the PA6 matrix due to lack of adequate interaction between the components. The addition of MMA-GMA compatibilizer neither promoted good phase dispersion or improved the mechanical properties of the blends, probably because the possible reactions are very slow and may not occur inside the extruder. On the other hand, the addition of the MMA-MA copolymer promotes better impact strength and good phase dispersion in the blend. The AES particles undergo significant reduction in the first stages of the mixture inside the extruder. The morphology observed for the injection molded specimens was correlated with the mechanical properties.

Adriane Bassani; Elias Hage Jr; Luiz A. Pessan; Ana V Machado; José A. Covas

2005-01-01

269

Thermoplastic Coating of Carbon Fibers, Annual Report, 1988 - 1989.  

Science.gov (United States)

A continuous powder coating system was developed for coating carbon fiber with LaRC-TPI (Langley Research Center-Thermoplastic Polyimide), a high-temperature thermoplastic polymide invented by NASA-Langley. The coating line developed used a pneumatic fibe...

D. D. Edie G. C. Lickfield L. E. Allen J. R. McCollum

1989-01-01

270

Separation and recovery of thermoplastics by froth floatation  

Energy Technology Data Exchange (ETDEWEB)

This paper describes efforts by Argonne National Laboratory to develop a froth flotation process for separating and recovering plastics from mixed plastics waste streams generated from shredding obsolete appliances and automobiles. A process for recovering and separating equivalent-density ABS and HIPS from obsolete appliances was developed and pilot-tested with a through-put of 1,250 lbs/hr. The basic process is outlined; unit operations and equipment are discussed, and material balances are presented. The resulting ABS product was analyzed and its physical and mechanical properties were established. Its properties resembled those of virgin, mid-grade ABS that is commercially sold today and is widely used by the automotive industry. Injection-molding tests were also conducted by automotive-components suppliers, using the 100% recovered ABS. Headlamp back-cans and automotive ventilation-system duct components were injection molded and the results showed that the recovered ABS met the specifications for these applications. These results confirmed that the recovered ABS can be used as a substitute for virgin plastic materials for molding highly complex automotive component designs, and in parts for other durable goods. Economic analysis of a commercial-scale system was also performed using manufacturers' equipment quotes and operating data from the pilot plant, and it predicts a simple payback of less than 2 years for plants producing about 850 tons per year of ABS.

Karvelas, D. E.; Jody, B. J.; Pomykala, J., Jr.; Daniels, E. J.

1999-10-22

271

Radiation effects on carbon fiber reinforced thermoplastics  

International Nuclear Information System (INIS)

Polyether-ether-ketone (PEEK) and a newly developed thermoplastic polyimide ''new-TPI'' were applied to carbon fiber reinforced plastic (CFRP) as a matrix resin. PEEK and new-TPI showed excellent resistance over 50 MGy to electron irradiation and the crosslinking proceeded predominantly by irradiation. The changes in mechanical properties induced by electron irradiation of the CFRP with the two resins were examined at various temperatures. The flexural strength and modulus measured at -196 and 25 degree C were scarcely affected up to 120 MGy and both the values measured at high temperature were increased with dose.

1993-01-01

272

Radiation effects on carbon fiber reinforced thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

Polyether-ether-ketone (PEEK) and a newly developed thermoplastic polyimide ``new-TPI`` were applied to carbon fiber reinforced plastic (CFRP) as a matrix resin. PEEK and new-TPI showed excellent resistance over 50 MGy to electron irradiation and the crosslinking proceeded predominantly by irradiation. The changes in mechanical properties induced by electron irradiation of the CFRP with the two resins were examined at various temperatures. The flexural strength and modulus measured at {minus}196 and 25{degree}C were scarcely affected up to 120 MGy and both the values measured at high temperature were increased with dose.

Sasuga, Tsuneo; Udagawa, Akira; Seguchi, Tadao [Japan Atomic Energy Research Institute, Gunma (Japan)

1993-12-31

273

Phase transitions in blends functionalized thermoplastics  

International Nuclear Information System (INIS)

Phase transitions, morphology and structure-property relationships in polymer blends based on functionalized thermoplastics, i.e. widely used polyurethanes and styrene-acrylic acid copolymers, were investigated by means of inter-expletive non-destructive methods. Wide and small angle X-ray scattering (WAXS and SAXS), dynamic mechanical thermal analysis, thermally stimulated depolarization currents techniques, dielectric relaxation spectroscopy and several physico-mechanical characterization techniques were used. The results obtained by the various techniques were critically compared to each other. (author)

2001-01-01

274

Low temperature properties of engineering thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

There are currently a wide variety of engineering thermoplastics available for a multitude of applications. Because of present market requirements, there has been a limited demand for test results of the physical properties of these materials at low temperatures. Several potential applications exist, however, and as a result, several engineering thermoplastic samples were tested at {minus}40 and {minus}56.6{degrees}C. Although not all these tests followed the procedures specified by the American Society of Testing and Materials precisely, the data represent comparative data that can be utilized for further design efforts. The evaluations included tensile testing, compressive properties, and Izod impact testing. Several materials with varied glass loadings were studied to determine the low temperature tendencies these molding compounds would exhibit. Some of the resins examined were: polyetheretherketone (PEEK), polytherimide (PEI), polyphenylene sulfide (PPS), polyethersulfone (PES), polyphthlamide (PPA), and a liquid crystal polymer (Vectra A130). In all cases, no detrimental effect was discerned over this temperature range; the study also indicated that improvements in the physical properties could be expected.

Kaye, C.J.

1991-01-01

275

Acetylation of rice straw for thermoplastic applications.  

UK PubMed Central (United Kingdom)

An inexpensive and biodegradable thermoplastic was developed through acetylation of rice straw (RS) with acetic anhydride. Acetylation conditions were optimized. The structure and properties of acetylated RS were characterized by fourier transform infrared (FTIR), solid-state (13)C NMR spectroscopy, X-ray diffractometer (XRD), scanning electron microscope (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results showed that acetylation of RS has successfully taken place, and comparing with raw RS, the degree of crystallinity decreased and the decomposition rate was slow. The acetylated RS has got thermoplasticity when weight ratio of RS and acetic anhydride was 1:3, using sulphuric acid (9% to RS) as catalyst in glacial acetic acid 35°C for 12h, and the dosage of solvent was 9 times RS, in which weight percent gain (WPG) of the modified RS powder was 35.5% and its percent acetyl content was 36.1%. The acetylated RS could be formed into transparent thin films with different amount of plasticizer diethyl phthalate (DEP) using tape casting technology.

Zhang G; Huang K; Jiang X; Huang D; Yang Y

2013-07-01

276

Influence of Addition of Thermoplastic Elastomer on Mechanical and Tribological Properties of Vapor-Grown-Carbon-Fiber Filled Polybutylene Terephthalate Composites  

Science.gov (United States)

In order to develop the new high-performance tribomaterials for mechanical and electrical micro-devices, the influence of adding thermoplastic elastomer (TPE) on the mechanical and tribological properties of vapor-grown-carbon-fiber (VGCF) filled polybutylene telephthalate (PBT) composites (VGCF/PBT) was investigated. In this study, three types of functionalized TPE based on styrene butadiene elastomer: epoxy group grafted SBS (SBS-EP), hydroxyl group grafted SEEPS (SEEPS-OH) and amine group grafted SBBS (SBBS-NH2) were added with PBT and VGCF/PBT composites. These composites were compounded with a twin screw extruder and injection-molded, and their morphology, tensile, impact and tribological properties were evaluated. The internal structure of the ternary composites (VGCF/PBT/TPE) was changed by the addition of TPE and VGCF. Moreover, the size of dispersed TPE particles changed with the types of functionalized TPE. The influence of the addition of TPE on the mechanical and tribological properties of VGCF/PBT was differed from each property item. Izod impact properties and wear resistance were remarkably improved with the addition of various functionalized TPE, however, the tensile properties and frictional coefficient were slightly changed by the addition. From the relation between various properties and internal structure of these ternary composites, it was found that the tensile elongation at break, izod impact strength and specific wear rate correlate closely with the size of dispersed TPE particles. It follows from these results that it may be possible to develop the new tribomaterials with sufficient balances of mechanical and tribological properties for micro-devices.

Naito, Takahito; Nishitani, Yosuke; Sekiguchi, Isamu; Ishii, Chiharu; Kitano, Takeshi

277

Sustainability of thermoplastic vinyl roofing membrane systems  

Energy Technology Data Exchange (ETDEWEB)

The International Council for Research and Innovation in Building and Construction (CIB-RILEM) has developed a framework for sustainable roofing based on a series of tenets divided into three key areas: preservation of the environment, conservation of energy, and extended roof life. This paper investigated the sustainability of thermoplastic vinyl roof membranes using these guidelines and the relevant tenets for roof system selection. Several tenets provided alternatives for minimizing the burden on the environment using non-renewable raw materials, conserving energy with thermal insulation, and extending the lifespan of all roof components by using long lasting membranes. A life cycle assessment was carried out to provide a quantitative framework for assessing the sustainability of roofing materials. It was found that the PVC membrane systems had a lesser impact on the environment than other competing systems.

Graveline, S. P. [Sika Sanarfil, Canton, (United States)

2010-07-01

278

Thermoplastic microcantilevers fabricated by nanoimprint lithography  

DEFF Research Database (Denmark)

Nanoimprint lithography has been exploited to fabricate micrometre-sized cantilevers in thermoplastic. This technique allows for very well defined microcantilevers and gives the possibility of embedding structures into the cantilever surface. The microcantilevers are fabricated in TOPAS and are up to 500 ?m long, 100 ?m wide, and 4.5 ?m thick. Some of the cantilevers have built-in ripple surface structures with heights of 800 nm and pitches of 4 ?m. The yield for the cantilever fabrication is 95% and the initial out-of-plane bending is below 10 ?m. The stiffness of the cantilevers is measured by deflecting the cantilever with a well-characterized AFM probe. An average stiffness of 61.3 mN m?1 is found. Preliminary tests with water vapour indicate that the microcantilevers can be used directly for vapour sensing applications and illustrate the influence of surface structuring of the cantilevers.

Greve, Anders; Keller, Stephan Urs

2010-01-01

279

Microfluidic device fabrication by thermoplastic hot-embossing.  

UK PubMed Central (United Kingdom)

Due to their low cost compatibility with replication-based fabrication methods, thermoplastics represent an exceptionally attractive family of materials for the fabrication of lab-on-a-chip platforms. A diverse range of thermoplastic materials suitable for microfluidic fabrication is available, offering a wide selection of mechanical and chemical properties that can be leveraged and further tailored for specific applications. While high-throughput embossing methods such as reel-to-reel processing of thermoplastics is an attractive method for industrial microfluidic chip production, the use of single chip hot embossing is a cost-effective technique for realizing high-quality microfluidic devices during the prototyping stage. Here we describe methods for the replication of microscale features in two thermoplastics, polymethylmethacrylate (PMMA) and polycarbonate (PC), using hot embossing from a silicon template fabricated by deep reactive-ion etching.

Yang S; Devoe DL

2013-01-01

280

Pen microfluidics: rapid desktop manufacturing of sealed thermoplastic microchannels.  

UK PubMed Central (United Kingdom)

A unique technique for the rapid fabrication of thermoplastic microfluidic chips is described. The method enables the realization of fully-sealed microchannels in around one hour while requiring only minimal infrastructure by taking advantage of a solvent swelling mechanism that allows raised features to be patterned on the surface of homogeneous thermoplastic materials. Patterning is achieved without photolithography by simply drawing the desired microchannel pattern onto the polymer surface using a suitable ink as a masking layer, either manually or under robotic control, followed by timed exposure to solvent vapor to yield a desired depth for the masked channel features. The channels are then permanently sealed through solvent bonding of the microchannel chip to a mating thermoplastic substrate. The process is demonstrated using cyclic olefin copolymer as a thermoplastic material, with fully operational microfluidic devices fabricated following a true desktop manufacturing model suitable for rapid prototyping.

Rahmanian O; DeVoe DL

2013-03-01

 
 
 
 
281

Influence of oxidized starch on the properties of thermoplastic starch.  

Science.gov (United States)

Thermoplastic starch was prepared by adding oxidized starches and glycerol together into starch. The addition of oxidized starch improved the rheological properties and also increased the toughness of thermoplastic starch. Compared with TPS30, the elongation at break increased from 126.8% to 152.5% when 5wt% OS 117% was added. Good compatibility of thermoplastic starch between the matrix and oxidized starch was confirmed by SEM. The addition of oxidized starch lowered the storage modulus and glass transition temperature (Tg) of thermoplastic starch, decreasing Tg from 34.1 to 30°C when 10 wt% OS117% was added. The thermal stability of blending was improved by adding oxidized starches, i.e. when 5 wt% OS70% was added, T5% increased from 134 to 156°C. PMID:23688492

Zhang, Yu-Rong; Wang, Xiu-Li; Zhao, Guo-Ming; Wang, Yu-Zhong

2013-04-12

282

Influence of oxidized starch on the properties of thermoplastic starch.  

UK PubMed Central (United Kingdom)

Thermoplastic starch was prepared by adding oxidized starches and glycerol together into starch. The addition of oxidized starch improved the rheological properties and also increased the toughness of thermoplastic starch. Compared with TPS30, the elongation at break increased from 126.8% to 152.5% when 5wt% OS 117% was added. Good compatibility of thermoplastic starch between the matrix and oxidized starch was confirmed by SEM. The addition of oxidized starch lowered the storage modulus and glass transition temperature (Tg) of thermoplastic starch, decreasing Tg from 34.1 to 30°C when 10 wt% OS117% was added. The thermal stability of blending was improved by adding oxidized starches, i.e. when 5 wt% OS70% was added, T5% increased from 134 to 156°C.

Zhang YR; Wang XL; Zhao GM; Wang YZ

2013-07-01

283

Forming of fiber reinforced thermoplastic sheets  

Energy Technology Data Exchange (ETDEWEB)

The development of fiber reinforced thermoplastic (FRTP) sheets has added a new dimension to the manufacturing industry. The ability of the thermoplastic matrix to soften and melt with the application of heat allows secondary processing of these composites. The material can be formed into components using conventional sheet metal forming processes with necessary modification. Ideally this opens the way for low cycle-time, non-labor intensive manufacturing processes. However, before there can be any wide scale application of the fiber reinforced sheet material, a better understanding is required regarding the formability of these reinforced sheets and the parameters influencing their forming characteristics. In sheet metal industry the term formability is described as the ease of forming and can be judged by various factors which may vary with the needs of a particular manufacturer. It is not always easy to prejudge formability as in many instances the actual sheet forming mechanism is quite complex. However, often a reasonable understanding of the process characteristics can be obtained through some relatively simple laboratory experiments. The present paper describes the results of a series of such tests namely hemispherical dome forming, cup drawing and vee bending using mainly polypropylene/glass fiber composite sheets with various fiber architecture, forming temperature and speed. Grid strain analysis has been applied to measure the magnitudes and directions of the principal strains and how they are influenced by fiber orientation. A kinematic approach has been shown to theoretically predict the deformation pattern with reasonable accuracy. Some salient features such as fiber buckling, sheet wrinkling, springback have been discussed in the context of forming process variables.

Bhattacharyya, D.; Burt, C.R.; Martin, T.A. [Univ. of Auckland (New Zealand). Dept. of Mechanical Engineering

1993-12-31

284

Characteristics and utilization of thermoplastic elastomers (TPE)-an overview  

Energy Technology Data Exchange (ETDEWEB)

The unique feature of thermoplastic elastomer, the combining of processing characteristics of thermoplastics with the physical properties of vulcanized rubber is reviewed. Highlights of TPE and its characteristics is aimed to generate interest in TPE, where SANS technique will be utilized for its characterization. The topics discussed include rubber elasticity, state of aggregation of polymers, microseparation in block copolymer system, application of TPE, and finally some notes in developing interest in TPE and SANS in Indonesia. (author)

Roestamsjah [R and D Center for Applied Chemistry, Indonesian Inst. of Sciences (Indonesia)

1998-10-01

285

Applications of lasers in metallization of thermoplastic and thermosetting polymers  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: This work focuses on the studies of chemical and physical changes induced by ArF-laser irradiation leading to formation of surfaces catalytically highly active and fully prepared for the direct electroless metallization for the case of thermoplastic and thermosetting polymer composites. The only pretreatment method for surface to be activated was laser irradiation. There are compared two polymer composites: thermoplastic and thermosetting with the same qualitative and quantitative contents of the selected copper compounds. Additionally, there is presented wide context of laser applications in electroless metallization of polymeric materials.Design/methodology/approach: The composites contained the same amount of copper(II) oxide (CuO) and copper(II) acetoacetate Cu(acac)2, while varied with the type of polymer matrix. There were chosen polyamide 6 as thermoplastic and polyurethane resin as thermosetting polymer matrixes. The composites were irradiated with various numbers of ArF excimer laser pulses (? = 193 nm) at constant fluence of 100 mJ/cm2. The metallization procedure of the laser-irradiated samples was performed by use of a commercial metallization bath and formaldehyde as a reducing agent. The samples were examined using FTIR, contact angle measurement and SEM techniques.Findings: It was found that laser irradiation induce catalytic properties in the studied composites. However, better catalytic properties were achieved for the thermoplastic than thermosetting polymer composites.Research limitations/implications: In order to better understand the differences in laser interactions between thermoplastic and thermosetting composites more examples of various polymer matrixes should be investigated.Practical implications: Suitable condition for laser irradiation of the composites associated with the best catalytic properties were proposes. Better catalytic properties were achieved for thermoplastic than thermosetting composite.Originality/value: Comparison of new thermoplastic and thermosetting polymer composites intended for laser direct electroless metallization is firstly reported in this article.

P. Rytlewski; M. ?enkiewicz

2013-01-01

286

Silicone thermoplastic sheeting for treatment of facial scars: an improved technique.  

UK PubMed Central (United Kingdom)

Silicone thermoplastic sheeting has been used successfully in the management of hypertrophic and keloid scars resulting from thermal burn injuries. A technique is described that incorporates silicone thermoplastic sheeting for fabrication of a compression face mask. This technique combines the moldability of thermoplastic splinting materials with the therapeutic surface of silicone, yielding the advantages of both in a one-step process.

Bradford BA; Breault LG; Schneid T; Englemeier RL

1999-06-01

287

A high throughput, controllable and environmentally benign fabrication process of thermoplastic nanofibers  

Science.gov (United States)

Continuous and uniform yarns of thermoplastic nanofibers were prepared via direct melt extrusion of immiscible blends of thermoplastic polymers with CAB and subsequent extraction removal of CAB. Ratios of thermoplastic/sacrificial polymers, melt viscosity, and interfacial tensions affect the formati...

288

Experimental investigation of laser-assisted thermoplastic tape consolidation  

Energy Technology Data Exchange (ETDEWEB)

An experimental investigation of a novel approach for manufacturing of thermoplastic matrix composites, is described. The technique is based on using laser energy as the focused heat source to melt the matrix material for subsequent consolidation, and appears to be particularly suited for thermoplastic filament winding opertions. An experimental set up is defined to produce multi ply rings, and the feasibility of this technique is demonstrated by discussing several samples that were produced using Ryton AC40-60 prepreg tapes. The quality of consolidation is examined through cross-sectional micrographs. 12 references.

Beyeler, E.; Phillips, W.; Guseri, S.I.

1988-01-01

289

Absorption depth profile of water on thermoplastic starch films  

Energy Technology Data Exchange (ETDEWEB)

It is well known that petroleum derived polymers are primary environmental contaminants. The study of new packing biodegradable materials has been the object of numerous papers in past years. Some of these new materials are the thermoplastic films derived from wheat starch. In the present paper, the authors study some of properties of wheat starch thermoplastic films, with various amounts of absorbed water, using photoacoustic spectroscopy techniques. The absorption depth profile of water in the starch substrate is determined for samples having a variable water level.

Bonno, B.; Laporte, J.L.; Paris, D.; D' Leon, R.T.

2000-01-01

290

Adsorption depth profile of water on thermoplastic starch films  

Energy Technology Data Exchange (ETDEWEB)

It is well known that petroleum derived polymers are primary environmental contaminants. The study of new packing biodegradable materials has been the object of numerous papers in past years. Some of these new materials are the thermoplastic films derived from wheat starch. In the present paper, the authors study some of properties of wheat starch thermoplastic films, with various amounts of absorbed water, using photoacoustic spectroscopy techniques. The absorption depth profile of water in the starch substrate is determined for samples having a variable water level.

Bonno, B.; Laporte, J.L.; Paris, D.; D' Leon, R.T.

2000-01-01

291

Thermoplastic polyurethane (TPU)/polyolefin (PO) blends  

Science.gov (United States)

Thermoplastic polyurethane (TPU) is a very important material with high versatility and superior physical properties. Melt blending TPU with metallocene polyolefin (PO) can lower TPU cost and improve polyolefin properties like abrasion resistance, adhesion, and paintability. Since TPU and non-polar PO blends are completely immiscible, efficient compatibilizers become the key issue and remain challenging. My main thesis work is to develop and study compatibilized TPU/PO blends. Although reactive compatibilization is considered the most efficient method, fast interfacial reactions between highly reactive functional groups are necessary to generate compatibilizers within usually short processing time. It is known that the urethane linkage (carbamate -NHCOO-) in TPU can reversibly dissociate to generate highly reactive isocyanates at melt temperatures. To find out the best reactive compatibilization, three approaches were employed on different molecular scales: (1) model urethane compound (dibutyl & dioctyl 4,4'-methylenebis(phenyl carbamate)) and small functional molecule (primary amine, secondary amine, hydroxyl, acid, anhydride, and epoxide) reactions at 200°C monitored by nuclear magnetic resonance and Fourier-transform infrared to examine the basic chemistry; (2) short, model TPU's with different chemical structures blended with functional polymers including poly(ethylene glycol) and polybutadiene to explore the effect of interface in immiscible mixtures; (3) melt blending of a commercial TPU with polypropylene (PP), further involving more complicated morphology, using different types of functional PP's (note: amine functional PP's were prepared by melt amination) as compatibilizers followed by rheological, morphological, thermal, and mechanical characterizations. Besides the core thesis project on TPU blends, other related work that has been accomplished includes: (1) adhesion between TPU and PP; (2) rheological properties of TPU; (3) block copolymer formation by reactive coupling. In the first work, the unique interfacial reactions were applied to promote TPU-PP adhesion that was quantified by asymmetric double cantilever beam test. In the second study, the abnormally high flow activation energy of TPU was explained by simultaneously investigating the effect of temperature and thermal degradation on the melt viscosity. In the third project, block copolymers were prepared by rapid reactive coupling of amine and isocyanate functional polymers and the reaction kinetics were also studied.

Lu, Qiwei

292

Thermoplastic Composite Wind Turbine Blades: An Integrated Design Approach  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis proposes a new structural design concept for future large wind turbine blades based on fully recyclable thermoplastic composites (TPC). With respect to material properties, cost and processing, reactively processed anionic polyamide-6 (APA-6) has been identified as the most promising the...

Joncas, S.

293

Study of structure and properties of thermoplastic polyurethanes  

International Nuclear Information System (INIS)

In the investigation on the effect or clay nano-composite on the structure and properties of thermoplastic polyurethanes (TPUs), the mechanical properties of TPUs had maximum values with 8 wt % clay content. The wide angle X-ray diffraction patterns showed that the glycerol propoxylate had better compatibility with the organoclay than poly(propylene glycol). (author)

2008-01-01

294

Bioinspired design and macroscopic assembly of poly(vinyl alcohol)-coated graphene into kilometers-long fibers.  

UK PubMed Central (United Kingdom)

Nacre is characterized by its excellent mechanical performance due to the well-recognized "brick and mortar" structure. Many efforts have been applied to make nacre-mimicking materials, but it is still a big challenge to realize their continuous production. Here, we prepared sandwich-like building blocks of poly(vinyl alcohol) (PVA)-coated graphene, and achieved high-nanofiller-content kilometers-long fibers by continuous wet-spinning assembly technology. The fibers have a strict "brick and mortar" layered structure, with graphene sheet as rigid brick and PVA as soft mortar. The mortar thickness can be precisely tuned from 2.01 to 3.31 nm by the weight feed ratio of PVA to graphene, as demonstrated by both atomic force microscopy and X-ray diffraction measurements. The mechanical strength of the nacre-mimicking fibers increases with increasing the content of PVA, and it rises gradually from 81 MPa for the fiber with 53.1 wt% PVA to 161 MPa for the fiber with 65.8 wt% PVA. The mechanical performance of our fibers was independent of the molecular weight (MW) of PVA in the wide range of 2-100 kDa, indicating that low MW polymers can also be used to make strong nanocomposites. The tensile stress of fibers immersed in PVA 5 wt% solution reached ca. 200 MPa, surpassing the values of nacre and most of other nacre-mimicking materials. The nacre-mimicking fibers are highly electrically conductive (?350 S m(-1)) after immersing in hydroiodic acid, enabling them to connect a circuit to illuminate an LED lamp.

Kou L; Gao C

2013-05-01

295

Poly(hydroxy amino ethers): Novel high-barrier thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

A visible trend in the area of food and beverage packaging is the ever increasing substitution of plastics for materials such as glass and metal. This research details the synthesis and properties of a new class of high barrier thermoplastics, namely poly(hydroxy amino ethers) (PHAE) prepared from stoichiometric reactions of primary amines or bis-sec-diamines with aromatic diglycidyl ethers in solution or in the melt. These polymers are true high molecular weight thermoplastics that can be fabricated by a variety of conventional processing techniques. The oxygen transmission rates of these polymers range from moderate (<5 BU) to very low (<0.1 BU), depending on the backbone structure of the PHAE in question. These extraordinary barrier properties are the consequence of a high degree of interchain cohesion due to hydrogen bonding interactions. The effect of polymer structure on oxygen transmission rate, glass transition temperature, and physical properties has been studied in detail.

Silvis, H.C.; Brown, C.N.; Kram, S.L.; White, J.E. [Dow Chemical Co., Midland, MI (United States)

1995-12-31

296

Development and Characterization of Amorphous Thermoplastic Matrix Graphene Nanocomposites  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of the present work is the development of amorphous thermoplastic matrix nanocomposites based on graphite nanoparticles. Different types of graphite were used, including unmodified graphite, graphene nanoplatelets and graphite intercalation compounds. Graphite intercalation compounds were subjected to thermal treatment to attain exfoliation of the nanofiller. The exfoliation process was studied by means of thermal analysis. The nanofillers and nanocomposites were characterized by means of X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) analysis. The nanocomposites were further characterized by means of mechanical and dielectric analysis. The flammability of the nanocomposites was also analyzed. Results obtained indicate that addition of the nanofiller allows improving the proprieties of the amorphous thermoplastic matrix. The effect of the degree of dispersion of the nanofiller is particularly relevant for the dielectric properties of the nanocomposites, whereas no direct correlation between degree of dispersion and mechanical properties can be observed.

Antonio Greco; Alessia Timo; Alfonso Maffezzoli

2012-01-01

297

Microstructure-property relationships in discontinuous fiber reinforced thermoplastic composites  

Energy Technology Data Exchange (ETDEWEB)

A novel Aligned Discontinuous Fiber (ADF) composite process has been developed to optimize performance and processability of discontinuous fiber thermoplastic composites. The principle feature of this process is the alignment of the fibers using electric fields in air. The successful control of the orientation state of the fibers using the ADF process led to the fabrication of micro-structure controlled discontinuous fiber composites and the subsequent investigation into the microstructure-property relationships of these materials.

Vyakarnam, M.N.; Drzal, L.T. [Michigan State Univ., East Lansing, MI (United States)

1996-12-31

298

Thermoplastic polymers surfaces for Dip-Pen Nanolithography of oligonucleotides  

Science.gov (United States)

Different thermoplastic polymers were spin-coated to prepare smooth surfaces for the direct deposition of end-group modified oligonucleotides by Dip-Pen Nanolithography. A study of the diffusion process was done in order to investigate the dependence of calibration coefficient and quality of deposited features on environmental parameters (temperature, relative humidity) and ink's molecular weight and functionality. The optimization of the process parameters led to the realization of high quality and density nanoarrays on plastics.

Suriano, Raffaella; Biella, Serena; Cesura, Federico; Levi, Marinella; Turri, Stefano

2013-05-01

299

Synthesis of biodegradable thermoplastic elastomers (BTPE) based on ?-caprolactone  

Directory of Open Access Journals (Sweden)

Full Text Available Aiming to mimic blood vessels, biodegradable thermoplastic elastomer (BTPE) is designed to be elastic, flexible and tough. A series of biodegradable triblock copolymers and poly(ester-urethanes) (PEU) based on ?-caprolactone have been synthesized and studied. The crystallinity of the poly(?-caprolactone) used as soft segment has been disrupted by incorporating either L-lactide (L-LA) units or trimethylene carbonate (TMC) units. Our studies suggest that soft segment composition does affect the mechanical properties significantly.

2010-01-01

300

Mechanical properties of carbon fibre reinforced thermoplastics for cryogenic applications  

International Nuclear Information System (INIS)

The high specific strength, the high specific stiffness and the excellent fatigue behaviour favours carbon fibre reinforced plastics (CFRP) as a supplement to metals for low temperature applications. The weakest link in the composite is the polymeric matrix, which is preloaded by thermal tensile strains and becomes brittle at low temperatures. Tough thermoplastic polymers show a higher cryogenic fracture strain than commonly used epoxy-matrix systems. Two carbon fibre reinforced tough thermoplastics (PEEK, PC) were tested at 293 K, 77 K and 5 K by tensile, bending and fatigue loading. It has been found, that the toughness of the matrices generally improves the static strength at low temperatures. In bidirectionally reinforced thermoplastics, transversal cracks appear in the matrix or in the boundary layer at composite strains below 0,2%, originated by the thermal preloading. The formation and development of the cracks depend on the fibre-matrix-bond and on the thickness of the composite layers. Fibre-misalignment results in a poor tension-tension fatigue endurance limit of less than 50% of the static strength. Further developments in the manufacturing process are necessary to improve the homogeneity of the composite structure in order to increase the long term fatigue behaviour. (orig.)

1989-01-01

 
 
 
 
301

Modular injection mold manufacturing in a selective laser sintering machine  

Science.gov (United States)

Reduced time to market places exacting requirements for the speed and quality of the design, manufacture and testing of new plastic parts. Traditionally, the greatest time for getting a new plastic product prototyped and tested is that for the mold fabrication phase. New metal materials for selective laser sintering (SLS) rapid prototyping technology allow direct mold fabrication for prototype plastic parts. Typically these molds are also useable for small scale production runs up to 50,000 parts. Using this technology prototype parts can be manufactured using the same materials and processes as used for the final product allowing testing of the whole manufacturing process for the prototype. This gives a company new opportunities to get a new or modified product to market faster and cheaper than by using traditional mold making processes. In this paper we describe this new technology and discuss how small and mid-size manufacturing companies can benefit from it.

Ikonen, Ilkka; Biles, William E.

1997-12-01

302

Validation of three-dimensional micro injection molding simulation accuracy  

DEFF Research Database (Denmark)

Data analysis and simulations on micro-molding experiments have been conducted. Micro molding simulations have been executed taking into account actual processing conditions implementation in the software. Various aspects of the simulation set-up have been considered in order to improve the simulation accuracy (i.e. decrease deviations from experimental values): injection speed profile, cavity injection pressure, melt and mold temperatures, three-dimensional mesh parameters, and material rheological characterization. Quality factors investigated for the quantitative comparisons were: short shot length, injection pressure profile, molding mass and flow pattern. The importance of calibrated micro molding process monitoring for an accurate implementation strategy of the simulation and its validation has been demonstrated. In fact, inconsistencies and uncertainties in the experimental data must be minimized to avoid introducing uncertainties in the simulation calculations. Simulations of bulky sub-100 milligrams micro molded parts have been validated and a methodology for accurate micro molding simulations was established.

Tosello, Guido Technical University of Denmark,

2011-01-01

303

Recycling of ligno-cellulosic and polyethylene wastes from agricultural operations in thermoplastic composites  

Science.gov (United States)

In the US, wood plastic composites (WPC) represent one of the successful markets for natural fiber-filled thermoplastic composites. The WPC typically use virgin or recycled thermoplastic as the substrate and wood fiber as the filler. A major application of the WPC is in non-structural building appli...

304

All-thermoplastic nanoplasmonic microfluidic device for transmission SPR biosensing.  

UK PubMed Central (United Kingdom)

Early and accurate disease diagnosis still remains a major challenge in clinical settings. Biomarkers could potentially provide useful tools for the detection and monitoring of disease progression, treatment safety and efficacy. Recent years have witnessed prodigious advancement in biosensor development with research directed towards rapid, real-time, label-free and sensitive biomarker detection. Among emerging techniques, nanoplasmonic biosensors pose tremendous potential to accelerate clinical diagnosis with real-time multiplexed analysis, rapid and miniaturized assays, low sample consumption and high sensitivity. In order to translate these technologies from the proof-of-principle concept level to point of care clinical diagnosis, integrated, portable devices having small footprint cartridges that house low-cost disposable consumables are sought. Towards this goal, we developed an all-polymeric nanoplasmonic microfluidic (NMF) transmission surface plasmon resonance (SPR) biosensor. The device was fabricated in thermoplastics using a simple, single step and cost-effective hot embossing technique amenable to mass production. The novel 3D hierarchical mold fabrication process enabled monolithic integration of blazed nanogratings within the detection chambers of a multichannel microfluidic system. Consequently, a single hard thermoplastic bottom substrate comprising plasmonic and fluidic features allowed integration of active fluidic elements, such as pneumatic valves, in the top soft thermoplastic cover, increasing device functionality. A simple and compact transmission-based optical setup was employed with multiplexed end-point or dual-channel kinetic detection capability which did not require stringent angular accuracy. The sensitivity, specificity and reproducibility of the transmission SPR biosensor was demonstrated through label-free immunodetection of soluble cell-surface glycoprotein sCD44 at clinically relevant picomolar to nanomolar concentrations.

Malic L; Morton K; Clime L; Veres T

2013-03-01

305

Induction Consolidation of Thermoplastic Composites Using Smart Susceptors  

Energy Technology Data Exchange (ETDEWEB)

This project has focused on the area of energy efficient consolidation and molding of fiber reinforced thermoplastic composite components as an energy efficient alternative to the conventional processing methods such as autoclave processing. The expanding application of composite materials in wind energy, automotive, and aerospace provides an attractive energy efficiency target for process development. The intent is to have this efficient processing along with the recyclable thermoplastic materials ready for large scale application before these high production volume levels are reached. Therefore, the process can be implemented in a timely manner to realize the maximum economic, energy, and environmental efficiencies. Under this project an increased understanding of the use of induction heating with smart susceptors applied to consolidation of thermoplastic has been achieved. This was done by the establishment of processing equipment and tooling and the subsequent demonstration of this fabrication technology by consolidating/molding of entry level components for each of the participating industrial segments, wind energy, aerospace, and automotive. This understanding adds to the nation's capability to affordably manufacture high quality lightweight high performance components from advanced recyclable composite materials in a lean and energy efficient manner. The use of induction heating with smart susceptors is a precisely controlled low energy method for the consolidation and molding of thermoplastic composites. The smart susceptor provides intrinsic thermal control based on the interaction with the magnetic field from the induction coil thereby producing highly repeatable processing. The low energy usage is enabled by the fact that only the smart susceptor surface of the tool is heated, not the entire tool. Therefore much less mass is heated resulting in significantly less required energy to consolidate/mold the desired composite components. This energy efficiency results in potential energy savings of {approx}75% as compared to autoclave processing in aerospace, {approx}63% as compared to compression molding in automotive, and {approx}42% energy savings as compared to convectively heated tools in wind energy. The ability to make parts in a rapid and controlled manner provides significant economic advantages for each of the industrial segments. These attributes were demonstrated during the processing of the demonstration components on this project.

Matsen, Marc R

2012-06-14

306

Biodegradation of thermoplastic starch/eggshell powder composites.  

UK PubMed Central (United Kingdom)

Thermoplastic starch (TPS) was prepared using compression molding and chicken eggshell was used as a filler. The effect of the eggshell powder (EP) on the properties of TPS was compared with the effect of commercial calcium carbonate (CC). The organic compound on the surface of the eggshell powder acted as a coupling agent that resulted in a strong adhesion between the eggshell powder and the TPS matrix, as confirmed by SEM micrographs. The biodegradation was determined by the soil burial test. The TPS/EP composites were more rapidly degraded than the TPS/CC composites. In addition, the eggshell powder improved the water resistance and thermal stability of the TPS.

Bootklad M; Kaewtatip K

2013-09-01

307

Blends of thermoplastic and elastomeric matrices with liquid crystalline polymers  

Energy Technology Data Exchange (ETDEWEB)

Liquid crystalline polymers (LCPs) present a unique balance of properties and, when added to thermoplastic (TP) or elastomeric (EL) matrices, can impart to the relevant blends specific properties that can be utilized for specific applications. As regards TP/LCP blends, the proclivity of LCPs to form fibrous structures and their low melt viscositiy allowed to obtain blends reinforced and easier to process than the pure TPs: particularly, depending on the LCP-TP structures and on the processing parameters, materials with improved processability, high modulus, enhanced impact strength and creeping resistance were obtained. As regards EL/LCP blends, that based on fluoroelastomers were in depth investigated and offered outstanding properties.

Roggero, A.; Pedretti, U.; La Mantia, F.P. [Eniricerche, Milanese (Italy)

1995-12-01

308

Nanoimprint technology nanotransfer for thermoplastic and photocurable polymers  

CERN Multimedia

Nanoscale pattern transfer technology using molds is a rapidly advancing area and one that has seen much recent attention due to its potential for use in nanotechnology industries and applications. However, because of these rapid advances, it can be difficult to keep up with the technological trends and the latest cutting-edge methods. In order to fully understand these pioneering technologies, a comprehensive understanding of the basic science and an overview of the techniques are required. Nanoimprint Technology: Nanotransfer for Thermoplastic and Photocurable Polymers covers

Taniguchi, Jun; Mizuno, Jun; Saito, Takushi

2013-01-01

309

Advances in PAS-2 thermoplastic prepregs and composites  

Energy Technology Data Exchange (ETDEWEB)

A family of polyarylene sulfide polymers is being developed as thermoplastic engineering resins. These resins have high temperature mechanical performance, good mechanical strength, and good solvent resistance. The newest member of this family of resins is PAS-2 amorphous polyarylene sulfide. One potential application for this amorphous resin is as a matrix for high performance composites. The amorphous polyarylene sulfide resin has been formed into unidirectional prepreg tapes. These tapes have been molded into laminates of excellent quality. Recently, new levels of performance in mechanical properties and processing have been achieved.

Lee, D.M.; Register, D.F.; Lindstrom, M.R.; Campbell, R.W.

1988-04-01

310

Interlaminate Deformation in Thermoplastic Composite Laminates: Experimental-Numerical Correlation  

Directory of Open Access Journals (Sweden)

Full Text Available The interlaminar deformation behaviors of thermoplastic AS4/PEEK composite laminates subjected to static tensile loading are investigated by means of microscopic moiré interferometry with high spatial resolution. The fully threedimensional orthotropic elastic-plastic analysis of interlaminar deformation for the thermoplastic laminates is developed in this paper, and used to simulate the stress-strain curves of tensile experiment for its angle-ply laminates. Under uniaxial tensile loading, the 3D orthotropic elastic-plastic FE analysis and microscopic moiré interferometry of interlaminar deformations are carried out for the [±25]S4 laminates. The quantitative local-filed experimental results of interlaminar shear strain and displacements at freeedge surface of the laminate are compared with corresponding numerical results of the orthotropic elastic-plastic FE model. It is indicated that the numerical tensile stressstrain curves of angle-ply laminates computed with 3D orthotropic elastic-plastic model are agree with experimental results. The numerical interlaminar displacement U and shear strain ?xz are also consistent with the experimental results obtained by moiré interferometry. It is expected the elastic-plastic interlaminar stresses and deformations analysis for the optimal design and application of AS4/PEEK laminates and its structures.

Shen M.; Tong J.; Wang S.; Fang Y.

2010-01-01

311

Development of thermo-plastic heating and compaction facility  

International Nuclear Information System (INIS)

Low- and intermediate-level radioactive wastes consist of spent resin, spent filter, concentrated waste and dry active waste(DAW) and they are solidified or packaged into drums or high integrated containers(HICs). DAWs occupy 50 percent of all low- and intermediate-level radioactive wastes generated from nuclear power plants in Korea. Incinerable wastes in the DAWs are about 60 percent. Therefore, it is very important for us to reduce the volume of incinerable wastes in DAWs. Experience of supercompaction turned out that thermo-plastic wastes have a swelling effect after supercompaction process due to their repulsive power. And the thermo-plastic heating and compaction facility has been developed by KEPCO. In conclusion, heating and compaction facility can reduce the volume of DAWs as well as upgrade the quality of treated wastes, because the swelling effect by repulsive power after compaction is removed, final wastes form the shape of block and they have no free-standing water in the wastes. Plan for practical use is that this facility will be installed in other nuclear power plants in Korea in 1999. (Cho, G. S.). 1 tab., 2 figs.

1998-01-01

312

Biodeterioration studies of thermoplastics in nature using indigenous bacterial consortium  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Thermoplastics, poly vinyl chloride and low-density polyethylene were treated in the presence of indigenously developed bacterial consortium in laboratory and natural conditions. The consortium was developed using four bacteria, selected on the basis of utilization of PVC as primary carbon source, namely P. otitidis, B. aerius, B. cereus and A. pedis isolated from the plastic waste disposal sites in Northern India. The comparative in-vitro treatment studies as revealed by (more) the spectral and thermal data, illustrated the relatively better biodegradation potential of developed consortium for PVC than the LDPE. Further, the progressive treatments of both the thermoplastics were conducted for three months under natural conditions. For this purpose, bioformulation of consortium was prepared and characterized for the viability up to 70 days of storage at 25±1ºC. The consortium treated polymer samples were monitored through SEM and FT-IR spectroscopy. Analytical data revealed the biodeterioration potential of the developed consortium for PVC and LDPE, which could help in disposing the plastic waste.

Anwar, Mohd. Shahbaz; Negi, Harshita; Zaidi, Mohd. Ghulam Haider; Gupta, Sanjay; Goel, Reeta

2013-06-01

313

Thermoplastic development of electroradiographic charge patterns for medical applications  

International Nuclear Information System (INIS)

[en] Ionography and Xeroradiography using toner development are much less sensitive than X-ray recording on screen-film systems. The aim of our work was to find a direct development technique with high sensitivity for electroradiographic charge patterns to obtain a relief pattern on a thermoplastic material. For the ionography as well as for the xeroradiography new carrier frequency techniques were developed which permit the screening of the signal charge due to the X-ray without screening the biascharge. Combining suitable plastic and elastic components we adapted the thermal and electric properties of the thermoplastics to the special requirements of electroradiography. With some of these optimized materials we achieved a charge sensitivity of 10-10 C/cm2 corresponding to a calculated X-ray sensitivity of 50 ?R. However, this X-ray sensitivity could not be achieved experimentally. Due to this and other drawbacks regarding picture quality, resistence to cycling, resolution and aging we conclude, that this technique is not suitable for practical applications. (orig.)

1982-01-01

314

Synthesis and characterization of energetic thermoplastic elastomers for propellant formulations  

Directory of Open Access Journals (Sweden)

Full Text Available Synthesis and characterization of energetic ABA-type thermoplastic elastomers for propellant formulations has been carried out. Following the working plan elaborated, the synthesis and characterization of Poly 3- bromomethyl-3-methyl oxetane (PolyBrMMO), Poly 3- azidomethyl-3-methyl oxetane (PolyAMMO), Poly 3,3-bis-azidomethyl oxetane (PolyBAMO) and Copolymer PolyBAMO/AMMO (by TDI end capping) has been successfully performed. The thermoplastic elastomers (TPEs) were synthesized using the chain elongation process PolyAMMO, GAP and PolyBAMO by diisocyanates. In this method 2.4-toluene diisocyanate (TDI) is used to link block A (hard and mono- functional)) to B (soft and di-functional). For the hard A-block we used PolyBAMO and for the soft B-block we used PolyAMMO or GAP.This is a joint project set up, some years ago, between the Chemistry Division of the Institute of Aeronautics and Space (IAE) - subordinated to the Brazilian Ministry of Defense - and the Fraunhofer Institut Chemische Technologie (ICT), in Germany. The products were characterized by different techniques as IR- and (1H,13C)NMR spectroscopies, elemental and thermal analyses. New methodologies based on FT-IR analysis have been developed as an alternative for the determination of the molecular weight and CHNO content of the energetic polymers.

Aparecida M. Kawamoto; José Irineu S.Oliveira; Rita de Cássia L. Dutra; Luis Claudio Rezende; Thomas Keicher; Horst Krause

2009-01-01

315

Polyolefin thermoplastic elastomer. Polyolefin kei netsu kasosei elastomer; Sumitomo TPE  

Energy Technology Data Exchange (ETDEWEB)

High quality and high grade polyolefin thermoplastic elastomers (TPE) with truly rubber-like properties, good processability and good appearance have been developed and commercialized under the trade name of SUMITOMO TPE, 3000 series. The conception of TPE is outlined, and the newly developed SUMITOMO TPEs are introduced. The SUMITOMO TPEs are the materials with low specific gravity well matched to the trend of lighter weight products, and possess all the general features of thermoplastic elastomer. They have good heat and cold resisting properties with wide applicable temperature ranges. Their weather-fastness and ozone proof property are excellent. The chemical resistances against acid, alkali and polar solvents are also excellent. They have low hydroscopicity and good electrical insulating properties. They can be blended with suh general purpose polyolefin as PP, PE, etc., and enable bicolor molding. They can also be blended with paint and pigment for any coloring, and are of low cost for their excellent properties. In particular, they are truly rubber-like, having good balanced physical properties and processability. 20 refs., 15 figs., 12 tabs.

Ibuki, Koichiro; Hikasa, Tadashi; Daimon, Akio; Hamanaka, Tatsuo (Sumitomo Chemical Co., Ltd., Osaka (Japan))

1989-11-27

316

Stress-induced structural changes in thermoplastic composites  

Energy Technology Data Exchange (ETDEWEB)

Polymeric Composites: Cyclic stress effects on PEEK (Poly-ether-ether-ketone) matrix thermoplastic composite system were examined by thermal-analysis techniques: DSC (Differential Scanning Calorimeter), DMA (Dynamic Mechanical Analysis), TMA (Thermomechanical Analysis), TGA (Thermogravimetric Analysis), TMA (Thermomechanical Analysis), TGA (Thermogravimetric Analysis), DGT (Density Gradient Technique), and WAXS (Wide angle X-ray Scattering). These measurements identified for the first time stress-induced crystallization of PEEK below the glass transition temperature (Tg). Also, PEEK crystallization above T[sub g] was kinetically studied by DSC and DMA, and a previously developed dual-crystallization methodology was extended to account for the influence of stress on crystallization. Finally, a fatigue kinetic model for un-notched PEEK films and a crack propagation model for PEEK composites were also developed providing a relation between matrix morphology and end-use performance. Collectively, this work established the importance of structural changes in thermoplastic-based composites that can be both monitored and influenced by dynamic (cyclic) mechanical experiments.

Kitano, A.

1991-01-01

317

Dielectric characterization of PCL-based thermoplastic materials for microwave diagnostic and therapeutic applications.  

UK PubMed Central (United Kingdom)

We propose the use of a polycaprolactone (PCL)-based thermoplastic mesh as a tissue-immobilization interface for microwave imaging and microwave hyperthermia treatment. An investigation of the dielectric properties of two PCL-based thermoplastic materials in the frequency range of 0.5-3.5 GHz is presented. The frequency-dependent dielectric constant and effective conductivity of the PCL-based thermoplastics are characterized using measurements of microstrip transmission lines fabricated on substrates comprised of the thermoplastic meshes. We also examine the impact of the presence of a PCL-based thermoplastic mesh on microwave breast imaging. We use a numerical test bed comprised of a previously reported 3-D anatomically realistic breast phantom and a multi-frequency microwave inverse scattering algorithm. We demonstrate that the PCL-based thermoplastic material and the assumed biocompatible medium of vegetable oil are sufficiently well matched such that the PCL layer may be neglected by the imaging solution without sacrificing imaging quality. Our results suggest that PCL-based thermoplastics are promising materials as tissue immobilization structures for microwave diagnostic and therapeutic applications.

Aguilar SM; Shea JD; Al-Joumayly MA; Van Veen BD; Behdad N; Hagness SC

2012-03-01

318

Preparation and characterization of thermoplastic starch/zein blends  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Blends of starch and zein plasticized with glycerol were prepared by melting processing in an intensive batch mixer connected to a torque rheometer at 160 °C. The resulting mixtures were compression molded and then characterized by scanning electron microscopy, differential scanning calorimetry, wide-angle X ray diffraction and water-absorption experiments. The blends were immiscible, showing two distinct phases of starch and zein. The water uptake at equilibrium and (more) its diffusion coefficient were determined. The water uptake at equilibrium decreased with increasing zein content. The diffusion coefficient fell sharply on addition of 20% zein and remained constant as zein content was increased. No appreciable effect of zein on starch crystallization was observed by X ray diffraction. The use of zein in thermoplastic starch compositions causes a decrease in the water sensitivity of these materials and lower its melt viscosity during processing making zein a suitable and very promising component in TPS compositions.

Corradini, Elisângela; Carvalho, Antonio José Felix de; Curvelo, Antonio Aprigio da Silva; Agnelli, José Augusto Marcondes; Mattoso, Luiz Henrique Capparelli

2007-09-01

319

Multiphase design of autonomic self-healing thermoplastic elastomers  

Science.gov (United States)

The development of polymers that can spontaneously repair themselves after mechanical damage would significantly improve the safety, lifetime, energy efficiency and environmental impact of man-made materials. Most approaches to self-healing materials require the input of external energy, healing agents, solvent or plasticizer. Despite intense research in this area, the synthesis of a stiff material with intrinsic self-healing ability remains a key challenge. Here, we show a design of multiphase supramolecular thermoplastic elastomers that combine high modulus and toughness with spontaneous healing capability. The designed hydrogen-bonding brush polymers self-assemble into a hard-soft microphase-separated system, combining the enhanced stiffness and toughness of nanocomposites with the self-healing capability of dynamic supramolecular assemblies. In contrast to previous self-healing polymers, this new system spontaneously self-heals as a single-component solid material at ambient conditions, without the need for any external stimulus, healing agent, plasticizer or solvent.

Chen, Yulin; Kushner, Aaron M.; Williams, Gregory A.; Guan, Zhibin

2012-06-01

320

Creep of thermoplastic polyurethane reinforced with ozone functionalized carbon nanotubes  

Directory of Open Access Journals (Sweden)

Full Text Available This work focused on the mechanical behavior, especially creep resistance, of thermoplastic polyurethane (TPU) filled with ozone-treated multi-walled carbon nanotubes (MWCNTs). It was found that the ozone functionalization of MWCNTs could improve their dispersion and interfacial adhesion to the TPU matrix as proved by scanning electron microscope and Raman spectrometer. It finally contributed to the enhancement of Young’s modulus and yield strength of TPU/MWCNT composites. Moreover, the creep resistance and recovery of MWCNT/TPU composites revealed a significant improvement by incorporating ozone functionalized MWCNTs. The strong interaction between the modified MWCNTs and TPU matrix would enhance the interfacial bonding and facilitate the load transfer, resulting in low creep strain and unrecovered strain.

Z. Zhang; Y. Jia; Z. M. Jiang; X. L. Gong

2012-01-01

 
 
 
 
321

Characterization of thermoplastic polyimide NEW-TPI reg sign  

Energy Technology Data Exchange (ETDEWEB)

Thermal and rheological properties of a commercial thermoplastic polyimide, NEW-TPI{reg sign}, were characterized. The as-received material possesses initially a transient crystallite form with a bimodal distribution in peak melting temperatures. After the meltings of the initial crystallite structures, the sample can be recrystallized by various thermal treatments. A bi-modal or single modal melting peak distribution is formed for annealing temperatures below or above 360C respectively. The recrystallized crystallinities are all transient in nature. The polymers are unable to be recrystallized after being subjected to elevated temperature annealing above 450C. The recrystallization mechanism was postulated, and a simple kinetics model was found to describe the behavior rather satisfactorily under the conditions of prolonged thermal annealing.

Hou, T.H. (Lockheed Engineering and Sciences Co., Hampton, VA (United States)); Reddy, R.M. (Old Dominion Univ., Norfolk, VA (United States))

1991-01-01

322

Multiphase design of autonomic self-healing thermoplastic elastomers.  

UK PubMed Central (United Kingdom)

The development of polymers that can spontaneously repair themselves after mechanical damage would significantly improve the safety, lifetime, energy efficiency and environmental impact of man-made materials. Most approaches to self-healing materials require the input of external energy, healing agents, solvent or plasticizer. Despite intense research in this area, the synthesis of a stiff material with intrinsic self-healing ability remains a key challenge. Here, we show a design of multiphase supramolecular thermoplastic elastomers that combine high modulus and toughness with spontaneous healing capability. The designed hydrogen-bonding brush polymers self-assemble into a hard-soft microphase-separated system, combining the enhanced stiffness and toughness of nanocomposites with the self-healing capability of dynamic supramolecular assemblies. In contrast to previous self-healing polymers, this new system spontaneously self-heals as a single-component solid material at ambient conditions, without the need for any external stimulus, healing agent, plasticizer or solvent.

Chen Y; Kushner AM; Williams GA; Guan Z

2012-06-01

323

Evaluation of in-service thermoplastic olefin (TPO) roofing membranes  

Energy Technology Data Exchange (ETDEWEB)

As part of a five-year investigation, mechanical (strength and elongation) and chemical (thermogravimetry and dynamic mechanical analysis) methods of evaluation are used in this paper to characterize in-service thermoplastic olefin (TOP) roof membranes. All the non-reinforced membranes meet the minimum thickness and tensile strength requirement as specified in the proposed ASTM standard. The polyester scrim reinforcement membranes had higher tensile strength and elongation values than those reinforced with random mat of short class fibers. The standard should consider defining the breaking strength in terms of stress instead of load and incorporating strain energy requirements at 23 C and {minus}40 C. The term TPO is confusing and very vague and the standard should consider differentiating between the different types of TPOs. Based on thermogravimetry, at least four different types of TPOs are currently in service. Lastly, the standard should consider using the glass transition temperature to monitor changes in membranes due to aging/weathering.

Simmons, T.R.; Paroli, R.M.; Liu, K.K.; Delgado, A.H.; Irwin, J.D.

1999-07-01

324

Thermoplastic Elastomers via polyolefin/Layered Silicate Nanocomposites  

Science.gov (United States)

Here we report the synthesis of fully exfoliated polyolefin nanocomposites via Surface-Initiated Ring Opening Metathesis Polymerization (SI-ROMP). Montmorillonite (MMT) clay platelets were rendered hydrophobic through ion exchange with alkyl-ammonium surfactants terminated with norbornene. We were then able to form block copolymer brushes of (substituted) norbornenes and cyclopentene via SI-ROMP. Subsequent hydrogenation yielded highly crystalline polyethylene and rubbery saturated polynorbornenes, thus giving a thermoplastic elastomer. Nanocomposites were prepared with different nanofiller percentages and were characterized for morphological (XRD, TEM), thermal (TGA, DSC), and mechanical (DMA, Rheology) properties. Complete exfoliation of nanocomposites was confirmed by XRD and TEM. A fraction of the polymer brushes were subsequently removed from their substrate by reverse ion exchange and characterized in parallel with their corresponding nanocomposite analogs. In this way we were able to directly assess the role of the filler particle in the thermal properties, melt rheology, morphology, and tensile properties.

Harsha Kalluru, Sri; Cochran, Eric W.

2013-03-01

325

Thermoplastic Polyurethane Elastomer Nanocomposites: Morphology, Thermophysical, and Flammability Properties  

Directory of Open Access Journals (Sweden)

Full Text Available Novel materials based on nanotechnology creating nontraditional ablators are rapidly changing the technology base for thermal protection systems. Formulations with the addition of nanoclays and carbon nanofibers in a neat thermoplastic polyurethane elastomer (TPU) were melt-compounded using twin-screw extrusion. The TPU nanocomposites (TPUNs) are proposed to replace Kevlar-filled ethylene-propylene-diene-monomer rubber, the current state-of-the-art solid rocket motor internal insulation. Scanning electron microscopy analysis was conducted to study the char characteristics of the TPUNs at elevated temperatures. Specimens were examined to analyze the morphological microstructure during the pyrolysis reaction and in fully charred states. Thermophysical properties of density, specific heat capacity, thermal diffusivity, and thermal conductivity of the different TPUN compositions were determined. To identify dual usage of these novel materials, cone calorimetry was employed to study the flammability properties of these TPUNs.

Wai K. Ho; Joseph H. Koo; Ofodike A. Ezekoye

2010-01-01

326

Microcellular Foams Based on High Performance Thermoplastic Nanocomposites  

International Nuclear Information System (INIS)

Foams from engineering thermoplastics nanocomposites based on Polyethersulphone and Polyethylene-2,6-naphthalate were prepared by using two different nanofillers (Silica nanoparticles and Graphite nanosheets). The effects of the nanofiller type and content on the foaming process was investigated and related to the density and cellular morphology of foams. The nanocomposite foams based on PES matrix exhibited improved nucleated cells both with SiO2 and Graphite nanosheets, but the density increased at all temperatures. On the contrary, nanocomposite foams based on PEN matrix showed different behaviors with the filler type. In this case, in fact, silica nanoparticles allowed lower densities when compared to the unfilled polymer foams, without influencing cells density. The Graphite nanosheets extended towards higher temperatures the foaming window of PEN nanocomposites, allowing densities as low as 0.15 at 260 deg. C.

2010-06-02

327

Forming arrangement for machines making receptacles out of thermoplastic material  

UK PubMed Central (United Kingdom)

An improved heat-forming deep-drawing molding machine for producing receptacles with thermoplastic banderoles, which machine includes a mandrel which coacts with a mold or a forming chamber for forming a closed banderole coil or loop. The mandrel has substantially the shape of the mold cavity. The mandrel slidably reciprocates in the mold cavity relative to the mold or the forming chamber and has a fixed transverse section relative thereto. The mandrel is composed of stationary and rotatable parts relative to the forming chamber. The rotating parts coact with the curved or round parts of the forming chamber or mold cavity. The rotating parts include suction channels which bias the banderole thereagainst so as to effect an advancing movement of the banderole in the forming chamber. The suction channels are operatively connected to a vacuum source.

DRONET JEAN-MARC

328

Processing Optimization of Deformed Plain Woven Thermoplastic Composites  

Science.gov (United States)

This research addresses the processing optimization of post-manufactured, plain weave architecture composite panels consisted of four glass layers and thermoplastic polyurethane (TPU) when formed with only localized heating. Often times, during the production of deep drawn composite parts, a fabric preform experiences various defects, including non-isothermal heating and thickness variations. Minimizing these defects is of utmost importance for mass produceability in a practical manufacturing process. The broad objective of this research was to implement a design of experiments approach to minimize through-thickness composite panel variation during manufacturing by varying the heating time, the temperature of heated components and the clamping pressure. It was concluded that the heated tooling with least area contact was most influential, followed by the length of heating time and the amount of clamping pressure.

Smith, John R.; Vaidya, Uday K.

2013-07-01

329

Extraction, characterization of components, and potential thermoplastic applications of camelina meal grafted with vinyl monomers.  

UK PubMed Central (United Kingdom)

Camelina meal contains oil, proteins, and carbohydrates that can be used to develop value-added bioproducts. In addition to containing valuable polymers, coproducts generated during the production of biofuels are inexpensive and renewable. Camelina is a preferred oilseed crop for biodiesel production because camelina is easier to grow and provides better yields. In this research, the components in camelina meal were extracted and studied for their composition, structure, and properties. The potential of using the camelina meal to develop thermoplastics was also studied by grafting various vinyl monomers. Oil (19%) extracted from camelina meal could be useful for food and fuel applications, and proteins and cellulose in camelina meal could be useful in the development of films, fibers, and thermoplastics. Thermoplastic films developed from grafted camelina meal had excellent wet tensile properties, unlike thermoplastics developed from other biopolymers. Camelina meal grafted with butylmethacrylate (BMA) had high dry and wet tensile strengths of 53.7 and 17.3 MPa, respectively.

Reddy N; Jin E; Chen L; Jiang X; Yang Y

2012-05-01

330

Attribute based selection of thermoplastic resin for vacuum infusion process : A decision making methodology  

DEFF Research Database (Denmark)

The composite industry looks toward a new material system (resins) based on thermoplastic polymers for the vacuum infusion process, similar to the infusion process using thermosetting polymers. A large number of thermoplastics are available in the market with a variety of properties suitable for different engineering applications, and few of those are available in a not yet polymerised form suitable for resin infusion. The proper selection of a new resin system among these thermoplastic polymers is a concern for manufactures in the current scenario and a special mathematical tool would be beneficial. In this paper, the authors introduce a new decision making tool for resin selection based on significant attributes. This article provides a broad overview of suitable thermoplastic material systems for vacuum infusion process available in today’s market. An illustrative example—resin selection for vacuum infused of a wind turbine blade—is shown to demonstrate the intricacies involved in the proposed methodology for resin selection.

Prabhakaran, R.T. Durai; Lystrup, Aage

2011-01-01

331

A review of recent developments in joining high-performance thermoplastic composites  

Science.gov (United States)

There is currently a great deal of interest in the use of thermoplastic polymers as matrices in fiber reinforced composites for high performance applications, such as those encountered in the aerospace industry. These materials include polyether ether ketone (PEEK), polyphenylene sulphide (PPS), polyetherimide (PEI), polyamideimide (PAI), polyamides, polyimides, and polysulphones. A literature review is provided on the different ways of joining high performance thermoplastic composites by adhesive and fusion bonding. The discussion on adhesive bonding includes examination of the performance of specific adhesive/thermoplastic combinations and of techniques for the preparation of composite surfaces: abrasion, etching, flame, and plasma treatments. Thermoplastic composite welding techniques discussed in depth include the following: heated press welding, resistance welding, induction welding, and ultrasonic welding. Works which examine or compare applications for these bonding techniques are also reviewed.

Cole, K. C.

1991-06-01

332

THERMAL DEGRADATION EFFECTS ON CONSOLIDATION AND BONDING IN THE THERMOPLASTIC FIBER-PLACEMENT PROCESS  

Science.gov (United States)

Effects of elevated temperature exposure during thermoplastic fiber placement on bonding and consolidation are investigated experimentally for AS 4/ polyetherketoneketone (PEKK) composite. Coupons of 24 layers are consolidated on the University of Delaware Center for Composite Ma...

333

Carbon nanotubes in blends of polycaprolactone/thermoplastic starch.  

UK PubMed Central (United Kingdom)

Despite the importance of polymer-polymer multiphase systems, very little work has been carried out on the preferred localization of solid inclusions in such multiphase systems. In this work, carbon nanotubes (CNT) are dispersed with polycaprolactone (PCL) and thermoplastic starch (TPS) at several CNT contents via a combined solution/twin-screw extrusion melt mixing method. A PCL/CNT masterbatch was first prepared and then blended with 20wt% TPS. Transmission and scanning electron microscopy images reveal a CNT localization principally in the TPS phase and partly at the PCL/TPS interface, with no further change by annealing. This indicates a strong driving force for the CNTs toward TPS. Young's model predicts that the nanotubes should be located at the interface. X-ray photoelectron spectroscopy (XPS) of extracted CNTs quantitatively confirms an encapsulation by TPS and reveals a covalent bonding of CNTs with thermoplastic starch. It appears likely that the nanotubes migrate to the interface, react with TPS and then are subsequently drawn into the low viscosity TPS phase. In a low shear rate/low shear stress internal mixer the nanotubes are found both in the PCL phase and at the PCL/TPS interface and have not completed the transit to the TPS phase. This latter result indicates the importance of choosing appropriate processing conditions in order to minimize kinetic effects. The addition of CNTs to PCL results in an increase in the crystallization temperature and a decrease in the percent crystallinity confirming the heterogeneous nucleating effect of the nanotubes. Finally, DMA analysis reveals a dramatic decrease in the starch rich phase transition temperature (?26°C), for the system with nanotubes located in the TPS phase.

Taghizadeh A; Favis BD

2013-10-01

334

Carbon nanotubes in blends of polycaprolactone/thermoplastic starch.  

Science.gov (United States)

Despite the importance of polymer-polymer multiphase systems, very little work has been carried out on the preferred localization of solid inclusions in such multiphase systems. In this work, carbon nanotubes (CNT) are dispersed with polycaprolactone (PCL) and thermoplastic starch (TPS) at several CNT contents via a combined solution/twin-screw extrusion melt mixing method. A PCL/CNT masterbatch was first prepared and then blended with 20wt% TPS. Transmission and scanning electron microscopy images reveal a CNT localization principally in the TPS phase and partly at the PCL/TPS interface, with no further change by annealing. This indicates a strong driving force for the CNTs toward TPS. Young's model predicts that the nanotubes should be located at the interface. X-ray photoelectron spectroscopy (XPS) of extracted CNTs quantitatively confirms an encapsulation by TPS and reveals a covalent bonding of CNTs with thermoplastic starch. It appears likely that the nanotubes migrate to the interface, react with TPS and then are subsequently drawn into the low viscosity TPS phase. In a low shear rate/low shear stress internal mixer the nanotubes are found both in the PCL phase and at the PCL/TPS interface and have not completed the transit to the TPS phase. This latter result indicates the importance of choosing appropriate processing conditions in order to minimize kinetic effects. The addition of CNTs to PCL results in an increase in the crystallization temperature and a decrease in the percent crystallinity confirming the heterogeneous nucleating effect of the nanotubes. Finally, DMA analysis reveals a dramatic decrease in the starch rich phase transition temperature (?26°C), for the system with nanotubes located in the TPS phase. PMID:23987335

Taghizadeh, Ata; Favis, Basil D

2013-05-31

335

Properties and performance of flax yarn/thermoplastic polyester composites  

DEFF Research Database (Denmark)

Aiming at demonstrating the potential of unidirectional natural fiber-reinforced thermoplastic composites in structural applications, textile flax yarn/thermoplastic polyester composites with variable fiber volume fractions have been manufactured by a filament-winding process followed by a vacuum-assisted compression molding process. The microstructure of the composites shows that the flax fiber yarns are well impregnated by the polyester matrix, and this supports the measured low porosity content of the composites. The experimental tensile modulus and ultimate tensile stress of the composites in the axial and transverse directions are well simulated by rule of mixtures models. In the axial direction, at a fiber volume fraction of 0.50, the experimental tensile modulus and ultimate tensile stress are 32 GPa and 350 MPa, respectively. In comparison, for glass fiber composites at a fiber volume fraction of 0.50, the tensile modulus and ultimate tensile stress are calculated to be 38 GPa and 1800 MPa, respectively. The flax yarn composites show better specific tensile modulus than the glass fiber composites with values of 23 GPa/g/cm3 and 20 GPa/g/cm3, respectively. An analysis of data from previous studies of unidirectional natural fibre composites demonstrates comparatively good reinforcement efficiency of the flax yarn fibers with an effective tensile modulus and ultimate tensile stress of the fibers in the area of 70 GPa and 800 MPa, respectively. Altogether, it is demonstrated that composites with high-quality textile flax yarn are well suited for structural applications when stiffness and weight saving are the central selection criteria.

Madsen, Bo; Mehmood, Shahid

2012-01-01

336

Synthesis of thermoplastic poly(ester-olefin) elastomers  

Directory of Open Access Journals (Sweden)

Full Text Available A series of thermoplastic poly(ester-olefin) elastomers, based on poly(ethylene-stat-butylene), HO-PEB-OH, as the soft segment and poly (butylene terephthalate), PBT, as the hard segment, were synthesized by a catalyzed transesterification reaction in solution. The incorporation of soft hydrogenated poly(butadiene) segments into the copolyester backbone was accomplished by the polycondensation of ?, ?-dihydroxyl telechelic HO-PEB-OH, (PEB Mn = 3092 g/mol) with 1,4-butanediol (BD) and dimethyl terephthalate (DMT) in the presence of a 50 wt-% high boiling solvent i.e., 1,2,4-trichlorobenzene. The molar ratio of the starting comonomers was selected to result in a constant hard to soft weight ratio of 60:40. The synthesis was optimized in terms of both the concentration of catalyst, tetra-n-butyl-titanate (Ti(OBu)4), and stabilizer, N,N'-diphenyl-p-phenylenediamine (DPPD), as well as the reaction time. It was found that the optimal catalyst concentration (Ti(OBu)4) for the synthesis of these thermoplastic elastomers was 1.0 mmol/mol ester and the optimal DPPD concentration was 1.0 wt-%. The extent of the reaction was followed by measuring the inherent viscosity of the reaction mixture. The effectiveness of the incorporation of the soft segments into the copolymer chains was proved by Soxhlet extraction with chloroform. The molecular structures, composition and the size of the synthesized poly(ester-butylene)s were verified by 1H NMR spectroscopy, viscometry of dilute solutions and the complex dynamic melt viscosity. The thermal properties of poly(ester-olefin)s were investigated by differential scanning calorimetry (DSC). The degree of crystallinity was also determined by DSC. The thermal and thermo-oxidative stability were investigated by thermogravimetric analysis (TGA). The rheological properties of poly(ester-olefin)s were investigated by dynamic mechanical spectroscopy in the melt and solid state.

Tanasijevi? Branka; Elkhaseh Salem F.K.; Nikoli? Marija S.; ?onlagi? Jasna A.

2004-01-01

337

Plastic wastes as modifiers of the thermoplasticity of coal  

Energy Technology Data Exchange (ETDEWEB)

Plastic waste recycling represents a major challenge in environmental protection with different routes now available for dealing with mechanical, chemical, and energy recycling. New concepts in plastic waste recycling have emerged so that now such wastes can be used to replace fossil fuels, either as an energy source or as a secondary raw material. Our objective is to explore the modification of the thermoplastic properties of coal in order to assess the possibility of adding plastic waste to coal for the production of metallurgical coke. Two bituminous coals of different rank and thermoplastic properties were used as a base component of blends with plastic wastes such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), poly(ethylene terephthalate) (PET), and acrilonitrile-butadiene-styrene copolymer (ABS). In all cases, the addition of plastic waste led to a reduction in Gieseler maximum fluidity, the extent of the reduction depending on the fluidity of the base coal, and the amount, the molecular structure, and the thermal behavior of the polymer. As a consequence, the amount of volatile matter released by the plastic waste before, during, and after the maximum fluidity of the coal and the hydrogen-donor and hydrogen-acceptor capacities of the polymer were concluded to be key factors in influencing the extent of the reduction in fluidity and the development of anisotropic carbons. The incorporation of the plastic to the carbon matrix was clearly established in semicokes produced from blends of a high-fluid coal and the plastic tested by SEM examination. 42 refs., 10 figs., 7 tabs.

M.A. Diez; C. Barriocanal; R. Alvarez [Instituto Nacional del Carbon (INCAR), Oviedo (Spain)

2005-12-01

338

Photoinitiated grafting of porous polymer monoliths and thermoplastic polymers for microfluidic devices  

Energy Technology Data Exchange (ETDEWEB)

A microfluidic device preferably made of a thermoplastic polymer that includes a channel or a multiplicity of channels whose surfaces are modified by photografting. The device further includes a porous polymer monolith prepared via UV initiated polymerization within the channel, and functionalization of the pore surface of the monolith using photografting. Processes for making such surface modifications of thermoplastic polymers and porous polymer monoliths are set forth.

Frechet, Jean M. J. (Oakland, CA); Svec, Frantisek (Alameda, CA); Rohr, Thomas (Leiden, NL)

2008-10-07

339

Repositioning accuracy of a commercially available thermoplastic mask system.  

UK PubMed Central (United Kingdom)

BACKGROUND AND PURPOSE: To evaluate the repositioning accuracy of a commercially available thermoplastic mask system for single dose radiosurgery treatments and fractionated treatment courses. PATIENTS AND METHODS: The repositioning accuracy of the Raycast-HP mask system (Orfit Industries, Wijnegem, Belgium) was analyzed. Twenty-two patients that were treated by intensity-modulated radiation therapy (IMRT) or intensity modulated radiosurgery (IMRS) for 43 intracranial lesions, underwent repeated CT imaging during their course of treatment, or as a positional control immediately before radiosurgery. We evaluated multiple anatomical landmark coordinates and their respective shifts in consecutive repeated CT-controls. An iterative optimization algorithm allowed for the calculation of the x, y and z-components of translation of the target isocenter(s) for each repeated CT, as well as rotation in the respective CT data sets. In addition to absolute target isocenter translation, the total magnitude vector (i.e. sum-vector) of isocenter motion was calculated along with patient rotations about the three principle axes. RESULTS: Fifty-five control CT datasets were analyzed for the target isocenter's respective position relative to the original treatment planning CT simulation. Mean target isocenter translation was 0.74+/-0.53, 0.75+/-0.60 and 0.93+/-0.78 mm in x, y and z-directions, respectively. Mean rotation about the x, y and z-axes was 0.67+/-0.66, 0.61+/-0.63 and 0.67+/-0.61 degrees, respectively. The respective median and mean magnitude vectors of isocenter translation were 1.28 and 1.59+/-0.84 mm. Analysis of the accuracy of the first setup control, representative of setup accuracy for radiosurgery treatments, compared with setup accuracy throughout a fractionated radiation treatment course were statistically equivalent (P= 0.15) thus indicating no measurable deterioration of setup accuracy throughout the treatment course. CONCLUSIONS: The analyzed Orfit thermoplastic mask system performed favorably compared with other mask immobilization systems for which peer-reviewed repositioning data exist. While the performance of the system for fractionated treatment courses was considered to be excellent, use of this mask system for radiosurgery immobilization in our clinic is subject to additional quality assurance measures to prohibit the delivery of treatments with target dislocations larger than 2 mm. The measured data in the present study should enable the users of this system to assign appropriate margins for the generation of planning target volumes.

Fuss M; Salter BJ; Cheek D; Sadeghi A; Hevezi JM; Herman TS

2004-06-01

340

Analysis of ageing of amorphous thermoplastic polymers by PVT analysis  

Science.gov (United States)

The aim of this work is the analysis of ageing phenomenon occurring in amorphous thermoplastic polymers below their glass transition temperature by pressure-volume-temperature (PVT) analysis. The ageing behavior of different polymers as a function of the heating and cooling rates has been widespread studied. Also, different works in literature are aimed to study the effect of the applied pressure on the glass transition behavior. Another relevant aspect related to the glass transition behavior is related to the ageing effects, which can also be influenced by the applied pressure. This is a very relevant issue, since most of the polymers, during ageing, are subjected to mechanical loading. PVT analysis was used to study the ageing of amorphous PET copolymer (PETg) at different pressure levels. Specific volume-temperature curves measured during the cooling and the heating steps were used for calculating the relaxed specific volume, showing that ageing effects increase with increasing applied pressure. The evolution of the fictive temperature as a function of time was calculated from experimental data.

Greco, Antonio; Maffezzoli, Alfonso; Gennaro, Riccardo; Rizzo, Michele

2012-07-01

 
 
 
 
341

Extrusion and characterization of thermoplastic starch sheets from "macho" banana.  

UK PubMed Central (United Kingdom)

UNLABELLED: Starch isolated from macho banana was oxidized by using 2.5% and 3.5% (w/w) of sodium hypochlorite. Native and oxidized starches with glycerol were processed using a conical twin screw extruder to obtain thermoplastic laminates or sheets, which were partially characterized. Oxidized banana starches presented higher moisture and total starch but lower ash, protein, lipids, and apparent amylose content than the native starch. Micrographs of sheets from oxidized starches showed wrinkles and cavities presumably caused by the plasticizer, but with less free glycerol and unplasticized starch granules than those from native starch. Sheets from oxidized starch showed a notorious increase in all thermal parameters (To, Tp, and ?H), mechanical properties (tensile strength, elongation at break, and elasticity), and solubility. Banana starch X-ray diffraction patterns corresponded to a mixture of the A- and B-type polymorphs, with apparently slightly higher crystallinity in oxidized specimens than in native starch. A similar trend was observed in the corresponding sheets. PRACTICAL APPLICATION: Due to the pollution problem caused by the conventional plastics, there has been a renewed interest in biodegradable sheets, because they may have the potential to replace conventional packaging materials. Banana starch might be an interesting raw material to be used as edible sheet, coating or in food packaging, and preservation, because it is biodegradable, cheap, innocuous, and abundant.

Alanís-López P; Pérez-González J; Rendón-Villalobos R; Jiménez-Pérez A; Solorza-Feria J

2011-08-01

342

Synthesis and characterization of thermoplastic polyurethane/nanoclay composites  

International Nuclear Information System (INIS)

In this study thermoplastic polyurethane (TPU) composites were obtained with different nanoclay contents (0, 1, 3 for all cases and 10 wt.% in some cases). The nanoclay Cloisite (registered) 30B (C30B) was dispersed in the TPU matrix by melt processing (twin-screw extruder; TPU-E composites) and during bulk polymerization (TPU-S composites). The synthesis method involved the two-step bulk polymerization of polyesterpolyol (molecular weight 2000 g mol-1) and diphenylmethanediisocyanate (MDI) with 1,4-butanediol as the chain extender. The dispersion state of the nanoclay particles and its effect on the mechanical properties of the composites, before and after ageing, was investigated. The characterization of TPU/nanoclay composites was carried out by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The mechanical characterization was performed through determination of the tensile and tear strengths. The TPU-E 3 wt.% composite showed the best improvement with increases in stress and strain at break (28% and 35%, respectively) and energy (88%), compared to the TPU-E (sample without nanoclay).

2009-03-01

343

Thermoplastic polyurethane synthesis using POSS as a chain modifier  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, thermoplastic polyurethanes (TPUs) were synthesized using the one-shot process in solution. To obtain the samples n-phenylaminopropyl polyhedric oligomeric silsesquioxane (POSS) was added as a chain modifier during the synthesis in four different amounts. The samples were characterized by infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and capillary rheometry. FTIR confirm the TPU attainment due the absence of the band at ~2253 cm-1 suggesting a complete conversion of the isocyanate terminations. The TGA showed that incorporation of POSS decreased the rate of mass loss of TPU under isothermal conditions. The flexible phase showed an enhanced stability to temperature, probably due to increased phase separation between the rigid and flexible domains. The DSC showed that incorporation of 0.4 wt. (%) of POSS increased the glass transition temperature of the flexible phase. Moreover, addition of POSS modified the melting behaviour, providing samples with a higher melting enthalpy compared to neat TPU as a consequence of the formation of larger crystals. The capillary rheometry analysis revels that the POSS addition showed a clear tendency toward higher intrinsic viscosities as the amount of POSS was increased.

Gabriel Hoyer Lopes; Janaína Junges; Rudinei Fiorio; Mara Zeni; Ademir José Zattera

2012-01-01

344

Thermoplastic polyurethane synthesis using POSS as a chain modifier  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english In this study, thermoplastic polyurethanes (TPUs) were synthesized using the one-shot process in solution. To obtain the samples n-phenylaminopropyl polyhedric oligomeric silsesquioxane (POSS) was added as a chain modifier during the synthesis in four different amounts. The samples were characterized by infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and capillary rheometry. FTIR confirm the TPU attainment due the ab (more) sence of the band at ~2253 cm-1 suggesting a complete conversion of the isocyanate terminations. The TGA showed that incorporation of POSS decreased the rate of mass loss of TPU under isothermal conditions. The flexible phase showed an enhanced stability to temperature, probably due to increased phase separation between the rigid and flexible domains. The DSC showed that incorporation of 0.4 wt. (%) of POSS increased the glass transition temperature of the flexible phase. Moreover, addition of POSS modified the melting behaviour, providing samples with a higher melting enthalpy compared to neat TPU as a consequence of the formation of larger crystals. The capillary rheometry analysis revels that the POSS addition showed a clear tendency toward higher intrinsic viscosities as the amount of POSS was increased.

Lopes, Gabriel Hoyer; Junges, Janaína; Fiorio, Rudinei; Zeni, Mara; Zattera, Ademir José

2012-08-01

345

Chemical imaging of thermoplastic olefin (TPO) surface architecture  

Energy Technology Data Exchange (ETDEWEB)

In the automotive industry, ethylene-propylene rubber (EPR) is mixed with polypropylene (PP) to form a thermoplastic olefin (TPO) for use as car bumpers and fascia. An adhesion promoting primer, chlorinated polyolefin (CPO), is spray coated onto the TPO surface to increase adhesion of the base and clear coat paints to the low surface free energy TPO substrate. The surface morphology of rubber domains within the CPO-coated TPO substrate contributes strongly to the material characteristics, including impact resistance and adhesion properties. However, elastomer-phase analysis is challenging using traditional microanalysis imaging techniques. The authors employ fluorescence and Raman chemical imaging to characterize the TPO architecture in order to better understand the surface properties of coated TPO. Fluorescence imaging makes use of Nile red (NR), a fluorescent solvatochromic dye, solvated in the primer, which is effective in differentiating rubber from polypropylene on the basis of large variations in the fluorescence quantum efficiency. Confocal fluorescence chemical imaging performed on T PO coated with NR-doped CPO shows a thin (2--3 {micro}m) layer of elastomer that has migrated to the TPO surface. Raman chemical imaging is in direct agreement with the fluorescence experiments by measuring the intrinsic vibrational signatures of CPO, EPR, and PP without the need for dyes or stains. Raman contrast is enhanced using cosine correlation analysis, a novel multivariate processing technique that provides chemical contrast on the basis of differences in spectral shape.

Morris, H.R. [Duquesne Univ., Pittsburgh, PA (United States). School of Pharmacy; Turner, J.F. II [Carnegie Mellon Univ., Pittsburgh, PA (United States). Center for Light Microscope Imaging and Biotechnology; Munro, B.; Ryntz, R.A. [Visteon Automotive Systems, Dearborn, MI (United States); Treado, P.J. [ChemIcon Inc., Pittsburgh, PA (United States)

1999-04-13

346

Synthesis and characterization of thermoplastic polyurethane/nanoclay composites  

Energy Technology Data Exchange (ETDEWEB)

In this study thermoplastic polyurethane (TPU) composites were obtained with different nanoclay contents (0, 1, 3 for all cases and 10 wt.% in some cases). The nanoclay Cloisite (registered) 30B (C30B) was dispersed in the TPU matrix by melt processing (twin-screw extruder; TPU-E composites) and during bulk polymerization (TPU-S composites). The synthesis method involved the two-step bulk polymerization of polyesterpolyol (molecular weight 2000 g mol{sup -1}) and diphenylmethanediisocyanate (MDI) with 1,4-butanediol as the chain extender. The dispersion state of the nanoclay particles and its effect on the mechanical properties of the composites, before and after ageing, was investigated. The characterization of TPU/nanoclay composites was carried out by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The mechanical characterization was performed through determination of the tensile and tear strengths. The TPU-E 3 wt.% composite showed the best improvement with increases in stress and strain at break (28% and 35%, respectively) and energy (88%), compared to the TPU-E (sample without nanoclay)

Pizzatto, Leandro [Autotravi Borrachas e Plasticos Ltda, Caxias do Sul (Brazil); Lizot, Analice; Fiorio, Rudinei [Departamento de Engenharia Quimica, Universidade de Caxias do Sul, Caxias do Sul (Brazil); Amorim, Cintia L.; Machado, Giovanna [Programa de Pos-Graduacao em Materiais, Universidade de Caxias do Sul, Caxias do Sul (Brazil); Giovanela, Marcelo [Departamento de Fisica e Quimica, Universidade de Caxias do Sul, Caxias do Sul (Brazil); Zattera, Ademir J. [Departamento de Engenharia Quimica, Universidade de Caxias do Sul, Caxias do Sul (Brazil); Crespo, Janaina S. [Grupo de Materiais Elastomericos, Universidade de Caxias do Sul, Caxias do Sul (Brazil)], E-mail: jscrespo@ucs.br

2009-03-01

347

Thermoplastic encapsulation of waste surrogates by high-shear mixing  

Energy Technology Data Exchange (ETDEWEB)

Brookhaven National Laboratory (BNL) has developed a robust, extrusion-based polyethylene encapsulation process applicable to a wide range of solid and aqueous low-level radioactive, hazardous and mixed wastes. However, due to the broad range of physical and chemical properties of waste materials, pretreatment of these wastes is often required to make them amenable to processing with polyethylene. As part of the scope of work identified in FY95 {open_quotes}Removal and Encapsulation of Heavy Metals from Ground Water,{close_quotes} EPA SERDP No. 387, that specifies a review of potential thermoplastic processing techniques, and in order to investigate possible pretreatment alternatives, BNL conducted a vendor test of the Draiswerke Gelimat (thermokinetic) mixer on April 25, 1995 at their test facility in Mahwah, NJ. The Gelimat is a batch operated, high-shear, high-intensity fluxing mixer that is often used for mixing various materials and specifically in the plastics industry for compounding additives such as stabilizers and/or colorants with polymers.

Lageraaen, P.R.; Kalb, P.D.; Patel, B.R.

1995-12-01

348

Performance of polymeric films based thermoplastic starch and organophilic clay  

International Nuclear Information System (INIS)

[en] The aim of this work was the development and investigation of the properties of flat films of LDPE/corn thermoplastic starch (TPS). A bentonite clay (Argel) was organophilized and characterized by XRD. This clay (1%) in both pristine and organophilic forms was added to the matrix (LDPE) and to LDPE/TPS systems with TPS contents varying from 5-20% w/w. The films manufactured (LDPE, LDPE/Clay, LDPE/TPS, LDPE/TPS/Clay) were characterized. Results indicate that water vapor permeability is dependent and increases with TPS content which was attributed to the higher affinity of water by TPS. TPS and Clay addition to LDPE led to significant changes in film properties with respect to the neat LDPE. In general,tensile and perforation forces increased with clay and TPS contents; the strength of thermo sealed films lowered with natural clay addition and increased with TPS and organoclay incorporation and, in general, dynamic friction coefficient decrease with organoclay and TPS addition. Best overall properties were obtained for the systems containing the organoclay and optimal properties were achieved for the 5%TPS10 LDPE1% ANO system. (author)

2010-01-01

349

Thermoplastic encapsulation of waste surrogates by high-shear mixing  

International Nuclear Information System (INIS)

[en] Brookhaven National Laboratory (BNL) has developed a robust, extrusion-based polyethylene encapsulation process applicable to a wide range of solid and aqueous low-level radioactive, hazardous and mixed wastes. However, due to the broad range of physical and chemical properties of waste materials, pretreatment of these wastes is often required to make them amenable to processing with polyethylene. As part of the scope of work identified in FY95 open-quotes Removal and Encapsulation of Heavy Metals from Ground Water,close quotes EPA SERDP No. 387, that specifies a review of potential thermoplastic processing techniques, and in order to investigate possible pretreatment alternatives, BNL conducted a vendor test of the Draiswerke Gelimat (thermokinetic) mixer on April 25, 1995 at their test facility in Mahwah, NJ. The Gelimat is a batch operated, high-shear, high-intensity fluxing mixer that is often used for mixing various materials and specifically in the plastics industry for compounding additives such as stabilizers and/or colorants with polymers

1995-01-01

350

Thermal Degradation, Mechanical Properties and Morphology of Wheat Straw Flour Filled Recycled Thermoplastic Composites  

Directory of Open Access Journals (Sweden)

Full Text Available Thermal behaviors of wheat straw flour (WF) filled thermoplastic compositeswere measured applying the thermogravimetric analysis and differential scanningcalorimetry. Morphology and mechanical properties were also studied using scanningelectron microscope and universal testing machine, respectively. Presence of WF inthermoplastic matrix reduced the degradation temperature of the composites. One for WFand one for thermoplastics, two main decomposition peaks were observed. Morphologicalstudy showed that addition of coupling agent improved the compatibility between WFs andthermoplastic. WFs were embedded into the thermoplastic matrix indicating improvedadhesion. However, the bonding was not perfect because some debonding can also be seenon the interface of WFs and thermoplastic matrix. In the case of mechanical properties ofWF filled recycled thermoplastic, HDPE and PP based composites provided similar tensileand flexural properties. The addition of coupling agents improved the properties ofthermoplastic composites. MAPE coupling agents performed better in HDPE while MAPPcoupling agents were superior in PP based composites. The composites produced with thecombination of 50-percent mixture of recycled HDPE and PP performed similar with theuse of both coupling agents. All produced composites provided flexural properties requiredby the ASTM standard for polyolefin-based plastic lumber decking boards.

Fatih Mengeloglu; Kadir Karakus

2008-01-01

351

Study on the Functionality of Nano-Precipitated Calcium Carbonate as Filler in Thermoplastics  

Science.gov (United States)

This research aims to investigate the functionality of nano-precipitated calcium carbonate (NPCC) as filler in thermoplastic resins based on property enhancement. Three types of thermoplastics were used: polyethylene (PE), polypropylene (PP) and polyvinyl chloride (PVC). The resins were evaluated by determining the effect of different NPCC loading on the chemical structure, thermal and mechanical properties of thermoplastics. Results showed that there was an interfacial bonding with the NPCC surface and the thermoplastics. Change in absorption peak and area were predominant in the PVC filled composite. There was a decreased in crystallinity of the PE and PP with the addition of filler. Tremendous increase on the tensile and impact strength was exhibited by the NPCC filled PVC composites while PE and PP composites maintained a slight increase in their mechanical properties. Nano-sized filler was proven to improve the mechanical properties of thermoplastics compared with micron-sized filler because nano-sized filler has larger interfacial area between the filler and the polymer matrix.

Basilia, Blessie A.; Panganiban, Marian Elaine G.; Collado, Archilles Allen V. C.; Pesigan, Michael Oliver D.; de Yro, Persia Ada

352

The use of Raman spectroscopy to study the reaction between an amine-terminated thermoplastic and epoxy resins  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Reactive thermoplastics are increasingly used as toughening modifiers for epoxy resins. A way to understand the influence of the reactive end-groups on the toughening and curing mechanisms is to observe in situ the reaction between the thermoplastic and the growing epoxy network. For this purpose, R...

van Overbeke, E; Legras, Roger; Carlier, Véronique; Devaux, Jacques; Carter, JT; Mcgrail, PT.

353

Design considerations for manufacturing carbon-fiber thermoplastic composites using microwave heating  

Energy Technology Data Exchange (ETDEWEB)

In an effort to lower the cost of manufacturing carbon-fiber thermoplastic composites, McDonnell Douglas Aerospace is investigating automated tape and fiber placement manufacturing methods. In these methods, structures are fabricated one ply at a time by applying heat to raise the bond line to the softening point of the thermoplastic and applying pressure to consolidate the ply to the structure being fabricated. Infrared, microwave, radio frequency and laser methods are being considered to quickly heat the thermoplastic resin to its consolidation temperature. The penetration of the heating power is different in each of these methods. We are currently conducting studies to determine if microwave heating has significant advantages over alternate heating methods and if so, how it should be incorporated into an actual manufacturing process. This paper describes the results of our studies concerning how the power density and penetration depth affect the manufacturing process.

Lind, A.C.; Wear, F.C. [McDonnell Douglas Aerospace, St. Louis, MO (United States)

1995-12-01

354

The essential work of fracture of thermoplastic orthodontic retainer materials.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To investigate whether oral cleansing agents affect the essential work of fracture (EWF) and plastic work of fracture (PWF) for two types of orthodontic thermoplastic retainer materials. MATERIALS AND METHODS: Polyethylene-terephthalate-glycol (PETG; Tru-Tain Splint) and polypropylene/ethylene-propylene rubber (PP-EPR) blend (Essix-C+) sheets were compared. For each material, six sets of 25 sheets were thermoformed into double-edge-notched-tension specimens; subsets of five specimens were formed with internotch distances (L) equal to 6, 8, 10, 12, or 14 mm, respectively. Sets were stored (160 hours, 25 degrees C) in air (DRY), distilled water (DW), Original Listerine (LIS), mint Crest ProHealth (CPH), 3% hydrogen peroxide (HP), or Polident solution (POL). Specimens were fractured in tension at 2.54 mm/min. Areas under load-elongation curves were measured to determine total work of fracture (W(f)). Linear regressions (W(f) vs L [n = 25]) yielded intercepts (EWF) and slopes (PWF). Ninety-five percent confidence intervals were used to evaluate differences in EWF and PWF estimates. RESULTS: PP-EPR blends showed higher EWFs after storage in HP vs storage in DW. PP-EPR blend showed higher EWFs after storage in CPH vs PETG. After HP storage, PP-EPR exhibited lower PWFs than with any other storage conditions. PP-EPR exhibited higher PWFs than PETG after storage in DRY, DW, and LIS. CONCLUSIONS: Compared with DW, none of the cleansers decreased the energy to initiate fracture. With one exception, no cleanser decreased the energy to continue plastic fracture extension. In PP-EPR blend, increased resistance to fracture initiation was observed with CPH and HP, yet, surprisingly, HP decreased resistance to plastic fracture growth.

Pascual AL; Beeman CS; Hicks EP; Bush HM; Mitchell RJ

2010-05-01

355

Dynamic viscoelasticities for short fiber-thermoplastic elastomer composites  

Energy Technology Data Exchange (ETDEWEB)

Dynamic moduli, E[prime] and E[double prime], and loss tangent tan [delta] were investigated for thermoplastic elastomers (TPEs), styrene-isoprene-styrene copolymers (SISs), styrene-butadiene-styrene copolymer (SBS), and Hytrel and composites reinforced by poly(ethylene terephthalate) (PET) short fibers. The styrenic TPEs have a typical rubbery behavior and the Hytrel TPE has medial characteristics between rubber and plastic. Both E[prime] and E[double prime] of the composites depended on the matrix as well as the fiber loading and fiber length. Based on the viewpoint of different extensibility between the fiber and the matrix elastomer, a triblock model was considered for estimating the storage modulus of the short fiber-TPE composites as follows: E[sub c] = [alpha] V[sub f]E[sub f] + [beta](1 [minus] V[sub f])E[sub m], where [alpha] and [beta] are the effective deformation coefficients for the fiber and the matrix elastomer, respectively. They can be quantitatively represented by modulus ratio M (= E[sub m]/E[sub f]) and fiber length L: [alpha] = (L[sup n] + k)M/(L[sup n]M + k), [beta] = (1 [minus] [alpha]V[sub f])/(1 [minus] V[sub f]), where the constants n and k are obtained experimentally. When k = 0.0222 and n = 0.45, E[sub c] of the TPE composites agreed well with the prediction of the proposed model. The relaxation spectrum of the composites showed a distinct main peak ascribed to the matrix elastomer, but no peak to the PET fiber.

Guo, Wuyun; Ashida, Michio (Kobe Univ., (Japan). Graduate School of Science and Technology)

1993-11-20

356

Final Report: Interphase Analysis and Control in Fiber Reinforced Thermoplastic Composites  

Energy Technology Data Exchange (ETDEWEB)

This research program builds upon a multi-disciplinary effort in interphase analysis and control in thermoplastic matrix polymer matrix composites (PMC). The research investigates model systems deemed of interest by members of the Automotive Composites Consortium (ACC) as well as samples at the forefront of PMC process development (DRIFT and P4 technologies). Finally, the research investigates, based upon the fundamental understanding of the interphases created during the fabrication of thermoplastic PMCs, the role the interphase play in key bulk properties of interest to the automotive industry.

Jon J. Kellar; William M. Cross; Lidvin Kjerengtroen

2009-03-14

357

EFFECT OF MALEIC ANHYDRIDE ON KENAF DUST FILLED POLYCAPROLACTONE/THERMOPLASTIC SAGO STARCH COMPOSITES  

Directory of Open Access Journals (Sweden)

Full Text Available The utilization of biodegradable polymers for various applications has been restricted mainly by its high cost. This report aims to study the water absorption and mechanical properties of kenaf dust-filled polycaprolactone/thermoplastic sago starch biodegradable composites as a function of filler loading and treatment with maleic anhydride. While water absorption in untreated biocomposites increased as a function of filler loading, treated biocomposites resulted in weight loss, whereby low molecular weight substances were dissolved into the aging medium. The kenaf dust imparts reinforcing effects on the biocomposites, resulting in improved mechanical properties. This is further attested by morphological studies in which kenaf dust was well dispersed in the polycaprolactone/ thermoplastic sago starch blend matrix. The addition of maleic anhydride into the polycaprolactone/thermoplastic sago starch blend resulted in a homogeneous mixture. At low filler loading, strain at break of the maleated polycaprolactone/thermoplastic sago starch blend increased at the expense of tensile strength and modulus. This is most likely due to the excessive dicumyl peroxide content, which caused chain scission of the polycaprolactone backbone. Tensile strength and modulus improved only when high filler loading was employed.

Siang Yee Chang,; Hanafi Ismail,; Qumrul Ashan

2012-01-01

358

Melting behavior of typical thermoplastic materials - An experimental and chemical kinetics study.  

UK PubMed Central (United Kingdom)

A medium-scale melting experiment rig was designed and constructed in this study. A detailed experimental study was conducted on the melting behavior and the chemical kinetic characteristics of three typical thermoplastic materials, including polypropylene (PP), polyethylene (PE) and polystyrene (PS). It is observed that the thermal decomposition of the thermoplastic materials mainly consists of three stages: the initial heating stage, the melting-dominated stage and the gasification-dominated stage. Melting of the materials examined takes place within a certain temperature range. The melting temperature of PS is the lowest, moreover, it takes the shortest time to be completely liquefied. To quantitatively represent the chemical kinetics, an nth-order reaction model was employed to interpret the thermal decomposition behavior of the materials. The calculated reaction order is largely in accordance with the small-scale thermal gravimetric analysis (TGA). The small difference between the results and TGA data suggests that there are some limitations in the small-scale experiments in simulating the behavior of thermoplastic materials in a thermal hazard. Therefore, investigating the thermal physical and chemical properties of the thermoplastic materials and their thermal hazard prevention in medium or large-scale experiments is necessary for the fire safety considerations of polymer materials.

Wang N; Tu R; Ma X; Xie Q; Jiang X

2013-08-01

359

Recycling of ligno-cellulosic and polyethylene wastes from agricultural operations in thermoplastic composites  

Science.gov (United States)

In the US, wood plastic composites (WPC) represent one of the successful markets for natural fiber-filled thermoplastic composites. In the past several years, the availability of good quality wood fiber has been diminishing and prices of wood and plastic have been increasing. Therefore, the vast qua...

360

Multichannel and repeatable self-healing of mechanical enhanced graphene-thermoplastic polyurethane composites.  

Science.gov (United States)

A novel self-healing material, which was fabricated using few-layered graphene (FG) and thermoplastic polyurethane (TPU) via a facile method, not only exhibits a mechanical enhanced property, but also can be repeatedly healed by various methods including infrared (IR) light, electricity and electromagnetic wave with healing efficiencies higher than 98%. PMID:23417742

Huang, Lu; Yi, Ningbo; Wu, Yingpeng; Zhang, Yi; Zhang, Qian; Huang, Yi; Ma, Yanfeng; Chen, Yongsheng

2013-02-18

 
 
 
 
361

Investigation on the mechanism of aminosilane-mediated bonding of thermoplastics and poly(dimethylsiloxane).  

Science.gov (United States)

A possible mechanism for the aminosilane-mediated room-temperature (RT) bonding of thermoplastics and poly(dimethylsiloxane) (PDMS) is presented. The plasma-activated thermoplastic or PDMS substrates were modified with alkoxy silanes having different organo functional groups, and their bonding characteristics were studied. Manual peeling tests revealed that strong bonding was realized only when the silane had a free amino group and at least two alkoxy groups on the silicon. Silanization was carried out in both aqueous and anhydrous conditions; bonding occurred readily at RT in the former case, but a longer incubation time or a higher temperature was needed for the latter. The presence of the silane on the surface was confirmed by contact-angle measurements and UV spectrophotometric, attenuated total reflectance infrared spectroscopic (ATR-IR) and X-ray photoelectron spectroscopic (XPS) analyses. In the case where the aminosilane was deposited from aqueous solution, the amino functionality of the silane-catalyzed siloxane bond formation between the silanol on the modified thermoplastic surface and the silanol of the plasma-activated PDMS. In the case of anhydrous phase deposition, the aminosilane first catalyzed the hydrolysis of the ethoxy groups on the silicon, and then, catalyzed the condensation between the silanol groups of both materials. Shelf life tests of the modified thermoplastics showed that the aminosilane was stable over 2 weeks, and that bonding occurred at RT when the substrates were soaked in water before bonding. PMID:23198791

Sunkara, Vijaya; Cho, Yoon-Kyoung

2012-12-12

362

[Effect of thermoplastic extrusion on lysine availability of chickpea (Cicer arietinum, L.) flour  

UK PubMed Central (United Kingdom)

The aim of this research was to evaluate lysine availability of chickpea (Cicer arietinum, L.) flour submitted to thermoplastic extrusion at three feed moisture levels (13%, 18% and 27%). It was verified that extrusion treatments reduced available lysine by 58% and 55% at 13% and 18% feed moisture levels. The major lysine loss, 71%, was verified at 27% feed moisture level.

Valim MF; Batistuti JP

2000-09-01

363

Extraction, characterization of components, and potential thermoplastic applications of camelina meal grafted with vinyl monomers.  

Science.gov (United States)

Camelina meal contains oil, proteins, and carbohydrates that can be used to develop value-added bioproducts. In addition to containing valuable polymers, coproducts generated during the production of biofuels are inexpensive and renewable. Camelina is a preferred oilseed crop for biodiesel production because camelina is easier to grow and provides better yields. In this research, the components in camelina meal were extracted and studied for their composition, structure, and properties. The potential of using the camelina meal to develop thermoplastics was also studied by grafting various vinyl monomers. Oil (19%) extracted from camelina meal could be useful for food and fuel applications, and proteins and cellulose in camelina meal could be useful in the development of films, fibers, and thermoplastics. Thermoplastic films developed from grafted camelina meal had excellent wet tensile properties, unlike thermoplastics developed from other biopolymers. Camelina meal grafted with butylmethacrylate (BMA) had high dry and wet tensile strengths of 53.7 and 17.3 MPa, respectively. PMID:22540881

Reddy, Narendra; Jin, Enqi; Chen, Lihong; Jiang, Xue; Yang, Yiqi

2012-05-07

364

Influence of chemical treatment on the tensile properties of kenaf fiber reinforced thermoplastic polyurethane composite  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study, the effect of polymeric Methylene Diphenyl Diisocyanate (pMDI) chemical treatment on kenaf (Hibiscus cannabinus) reinforced thermoplastic polyurethane (TPU/KF) was examined using two different procedures. The first consisted of treating the fibers with 4% pMDI, and the second involved...

Y. A. El-Shekeil; S. M. Sapuan; A. Khalina; E. S. Zainudin; O. M. Al-Shuja'a

365

Novel segmented thermoplastic polyurethanes elastomers based on tetrahydrofuran ethylene oxide copolyethers as high energetic propellant binders  

Energy Technology Data Exchange (ETDEWEB)

Novel thermoplastic polyurethane (TPU) elastomers based on copolyether (tetrahydrofuran ethylene oxide) as soft segments, isophorone diisocyanate and 1,4-butanediol as hard segments were synthesized for the purpose of using as propellant binders. In order to increase the miscibility of thermoplastic polyurethane elastomers with nitrate ester, polyethylene glycol (PEG) is incorporated in the co-polyether (tetrahydrofuran ethylene oxide) as soft segment. When the molecular weight and content of polyethylene glycol are controlled to 4000 and 6% of soft segments, respectively, the properties of thermoplastic polyurethane elastomers are most perfect. If plasticizing ratio of nitrate ester to thermoplastic polyurethane elastomers exceeds 4 no crystallinities are determined at room temperature. The propellant samples were prepared by a conventional absorption-rolling extrusion process and the mechanical and combustion properties evaluated afterwards. The maximum impulse reaches up to 265{proportional_to}270 s which is a little bit higher than that of a HTPB propellant. The measured results reveal a promising TPE propellant candidate which shows good processing temperature (<393 K) and excellent mechanical properties. An attracting feature which can be pointed out is that the burning rate pressure exponent reaches as low as 0.36 without the addition of burning rate catalysts. This enables an easy control of propellant combustion. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

Chen, Fu-Tai; Duo, Ying-Quan; Luo, Shan-Guo; Luo, Yun-Jun; Tan, Hui-Min [School of Chemical Engineering and Materials Science, Beijing Institute of Technology, Beijing 100081 (China)

2003-02-01

366

Damage detection in laminar thermoplastic composite materials by means of embedded optical fibers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper investigates the possibility of applying optical fibers as sensors for investigating low energy impact damage in laminar thermoplastic composite materials, in real time. Impact toughness testing by a Charpy impact pendulum with different loads was conducted in order to determine the metho...

Kojovi? Aleksandar M.; Živkovi? Irena D.; Brajovi? Ljiljana M.; Mitrakovi? Dragan; Aleksi? Radoslav R.

367

Diaphragm forming of continuous-fiber reinforced thermoplastics suitable for medium-scale production  

Energy Technology Data Exchange (ETDEWEB)

Sheet-form continuous fiber-reinforced thermoplastics can be processed with the diaphragm forming technology. Using a high-temperature resistant rubber diaphragm the cycle-time is reduced to less than two minutes. The consolidated laminate which consists of several thermoplastic prepregs is positioned between two diaphragms. These diaphragms are made out of silicone or fluorine rubber and can be used up to temperatures of 290 C for a long-term. They are clamped in two separate frames which can be closed airtight against each other. After closing the two frames the laminate is evacuated. The prepregs are heated up above the melting temperature of the thermoplastic matrix using a contact heating device. The heated laminate is transferred to the forming unit where air pressure is applied to one side of the diaphragms and the prepregs are formed into the cavity. Complex shaped geometries can be formed because of a homogeneous pressure distribution during processing and the relative thick diaphragms (1 mm) prevent the laminate from wrinkling during forming. After cooling in the cavity the formed part can be demoulded. During the whole process the thermoplastic prepregs stay between the diaphragms.

Michaeli, W.; Jehrke, M. [Institute of Plastics Processing, Aachen (Germany)

1993-12-31

368

Recycling of Ligno-Cellulosic and Polythylene Wastes from Agriculture Operations in Thermoplastic Composites  

Science.gov (United States)

In the US, wood plastic composites (WPC) represent one of the successful markets for natural fiber-filled thermoplastic composites. In the past several years, the availability of good quality wood fiber has been diminishing and prices of wood and plastic have been increasing. Therefore, the vast qua...

369

Chemical-assisted bonding of thermoplastics/elastomer for fabricating microfluidic valves.  

UK PubMed Central (United Kingdom)

Thermoplastics such as cyclic olefin copolymer (COC) and polymethylmethacrylate (PMMA) have been increasingly used in fabricating microfluidic devices. However, the state-of-the-art microvalve technology is a polydimethylsiloxane (PDMS)-based three-layer structure. In order to integrate such a valve with a thermoplastics-based microfluidic device, a bonding method for thermoplastics/PDMS must be developed. We report here a method to bond COC with PDMS through surface activation by corona discharge, surface modification using 3-(trimethoxysilyl)propyl methacrylate (TMSPMA), and thermal annealing. The method is also applicable to PMMA. The bonding strength between thermoplastics and PDMS was represented by the peeling force, which was measured using a method established by the International Organization for Standardization (ISO). The bonding strength measurement offered an objective and quantitative indicator for protocol optimization, as well as comparison with other PDMS-associated bonding methods. Using optimized bonding conditions, two valve arrays were fabricated in a COC/PDMS/COC device and cyclic operations of valve closing/opening were successfully demonstrated. The valve-containing devices withstood 100 psi (?689 KPa) without delamination. Further, we integrated such valve arrays in a device for protein separation and demonstrated isoelectric focusing in the presence of valves.

Gu P; Liu K; Chen H; Nishida T; Fan ZH

2011-01-01

370

Chemical-assisted bonding of thermoplastics/elastomer for fabricating microfluidic valves.  

Science.gov (United States)

Thermoplastics such as cyclic olefin copolymer (COC) and polymethylmethacrylate (PMMA) have been increasingly used in fabricating microfluidic devices. However, the state-of-the-art microvalve technology is a polydimethylsiloxane (PDMS)-based three-layer structure. In order to integrate such a valve with a thermoplastics-based microfluidic device, a bonding method for thermoplastics/PDMS must be developed. We report here a method to bond COC with PDMS through surface activation by corona discharge, surface modification using 3-(trimethoxysilyl)propyl methacrylate (TMSPMA), and thermal annealing. The method is also applicable to PMMA. The bonding strength between thermoplastics and PDMS was represented by the peeling force, which was measured using a method established by the International Organization for Standardization (ISO). The bonding strength measurement offered an objective and quantitative indicator for protocol optimization, as well as comparison with other PDMS-associated bonding methods. Using optimized bonding conditions, two valve arrays were fabricated in a COC/PDMS/COC device and cyclic operations of valve closing/opening were successfully demonstrated. The valve-containing devices withstood 100 psi (?689 KPa) without delamination. Further, we integrated such valve arrays in a device for protein separation and demonstrated isoelectric focusing in the presence of valves. PMID:21121689

Gu, Pan; Liu, Ke; Chen, Hong; Nishida, Toshikazu; Fan, Z Hugh

2010-12-01

371

Evaluation of a Thermoplastic Immobilization System for Breast and Chest Wall Radiation Therapy  

International Nuclear Information System (INIS)

[en] We report on the impact of a thermoplastic immobilization system on intra- and interfraction motion for patients undergoing breast or chest wall radiation therapy. Patients for this study were treated using helical tomotherapy. All patients were immobilized using a thermoplastic shell extending from the shoulders to the ribcage. Intrafraction motion was assessed by measuring maximum displacement of the skin, heart, and chest wall on a pretreatment 4D computed tomography, while inter-fraction motion was inferred from patient shift data arising from daily image guidance procedures on tomotherapy. Using thermoplastic immobilization, the average maximum motion of the external contour was 1.3 ± 1.6 mm, whereas the chest wall was found to be 1.6 ± 1.9 mm. The day-to-day setup variation was found to be large, with random errors of 4.0, 12.0, and 4.5 mm in the left-right, superior-inferior, and anterior-posterior directions, respectively, and the standard deviations of the systematic errors were found to be 2.7, 9.8, and 4.1 mm. These errors would be expected to dominate any respiratory motion but can be mitigated by daily online image guidance. Using thermoplastic immobilization can effectively reduce respiratory motion of the chest wall and external contour, but these gains can only be realized if daily image guidance is used.

2011-01-01

372

High-temperature thermoplastic strengthening of steels St3sp and 09G2S  

Energy Technology Data Exchange (ETDEWEB)

One of the promising trends of improving the mechanical properties of rolled metal is its thermoplastic treatment (TPT) at high (HTPT) and low (LTPT) temperatures. The method of TPT suggested by the All-Union Research Institute of Metallurgical Machinery Construction is a technological modification of the thermal-strain methods of strengthening steels and alloys. 8 refs., 3 tabs.

Ksenofontov, A.G.; Sinel`nikova, M.Yu.; Kozhevnikov, I.V. [N.E. Bauman Moscow State Technical Univ. (Russian Federation)] [and others

1992-01-01

373

Tailoring of thermomechanical properties of thermoplastic nanocomposites by surface modification of nanoscale silica particles  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thermoplastic nanocomposites based on linear polymethacrylates as matrix materials and spherical silica particles as fillers have been synthesized using the in situ free radical polymerization technqiue of methacrylate monomers in presence of specially functionalized SiO2 nanoparticulate fillers. Un...

Becker, Carsten; Krug, Herbert; Schmidt, Helmut K.

374

Positioning immobility technique by thermoplastic sheet for the three-dimension comformal radiation therapy of the abdominal and pelvic tumor  

International Nuclear Information System (INIS)

[en] Objective: To evaluate the clinical application value of positioning immobility technique by thermpolastic sheet for the three-dimension comformal radiation therapy(3D-CRT) of the abdominal and pelvic tumors. Methods: Eleven patients were immobilized with Topslane thermoplastic sheet to carry out the 3D-CRT. The field movements were measured and compared between before and after the set-up. Results: The inaccuracy of the process of 3D-CRT immobilized with Topslane thermoplastic sheet was within 5 mm. Conclusion: Positioning immobility technique by thermoplastic sheet is useful and practical for 3D-CRT of the abdominal and pelvic tumors. (authors)

2006-01-01

375

Review of potential processing techniques for the encapsulation of wastes in thermoplastic polymers  

International Nuclear Information System (INIS)

[en] Thermoplastic encapsulation has been extensively studied at Brookhaven National Laboratory's (BNL) Environmental and Waste Technology Center (EWTC) as a waste encapsulation technology applicable to a wide range of waste types including radioactive, hazardous and mixed wastes. Encapsulation involves processing thermoplastic and waste materials into a waste form product by heating and mixing both materials into a homogeneous molten mixture. Cooling of the melt results in a solid monolithic waste form in which contaminants have been completely surrounded by a polymer matrix. Heating and mixing requirements for successful waste encapsulation can be met using proven technologies available in various types of commercial equipment. Processing techniques for thermoplastic materials, such as low density polyethylene (LDPE), are well established within the plastics industry. The majority of commercial polymer processing is accomplished using extruders, mixers or a combination of these technologies. Extruders and mixers are available in a broad range of designs and are used during the manufacture of consumer and commercial products as well as for compounding applications. Compounding which refers to mixing additives such as stabilizers and/or colorants with polymers, is analogous to thermoplastic encapsulation. Several processing technologies were investigated for their potential application in encapsulating residual sorbent waste in selected thermoplastic polymers, including single-screw extruders, twin-screw extruders, continuous mixers, batch mixers as well as other less conventional devices. Each was evaluated based on operational ease, quality control, waste handling capabilities as well as degree of waste pretreatment required. Based on literature review, this report provides a description of polymer processing technologies, a discussion of the merits and limitations of each and an evaluation of their applicability to the encapsulation of sorbent wastes

1995-01-01

376

Hazardous Air Pollutant Emissions from Process Units in the Thermoplastics Manufacturing Industry. Basis and Purpose Document for Proposed Standards.  

Science.gov (United States)

The document provides the background information and rationale for the decisions made in the (proposed) standards setting process for the thermoplastics manufacturing industry. The affected industry is described, the baseline organic HAP emissions are pre...

1995-01-01

377

Influence of Engage® copolymer type on the properties of Engage®/silicone rubber-based thermoplastic dynamic vulcanizates  

Directory of Open Access Journals (Sweden)

Full Text Available Thermoplastic vulcanizates (TPVs) are a special class of thermoplastic elastomers, which are produced by simultaneously mixing and crosslinking a rubber with a thermoplastic polymer at an elevated temperature. Peroxide-cured TPVs based on blends of silicone rubber and thermoplastic Engage of two different types, mainly ethylene-octene and ethylenebutene copolymers at different blend ratios have been developed. A detailed comparative study of ethylene-octene vs. ethylene-butene based TPVs are mainly focused in this paper. These TPVs exhibit very good overall mechanical and electrical properties. With increasing amount of Engage in the blends at a fixed concentration of peroxide and coagent, tensile strength, modulus and hardness of the TPVs were found to increase considerably. Ageing characteristics and recyclability of silicone rubber based TPVs are also found excellent. Rheological studies confirm the pseudoplastic nature of these TPVs.

2008-01-01

378

Thermoplastic hybrid materials: Polyhedral oligomeric silsesquioxane (POSS) reagents, linear polymers, and blends  

Energy Technology Data Exchange (ETDEWEB)

Polyhedral Oligomeric SilSesquioxanes (POSS) are structurally well defined cage-like molecules represented by the generic formula (RSiO{sub 1.5}){sub n}. POSS compounds possess a unique hybrid composition with an oxygen to silicon ratio of 1.5, intermediate between that for silica and silicone. An entire monomer catalogue (chemical tree) of hybrid POSS-based reagents suitable for polymerization and grafting reactions has been developed from R{sub 7}Si{sub 7}O{sub 9}(OH){sub 3} and related precursors. POSS reagents containing no more than one or two reactive groups enable the preparation of hybrid materials with desirable physical properties such as thermoplasticity, and elasticity. An overview of the synthesis of POSS monomers and thermoplastic POSS-acrylic polymers is given. The thermal and physical properties for POSS-acrylic monomers, homopolymers, and copolymers, and blends with poly(methylmethacrylate) are described.

Lichtenhan, J.D. [Phillips Lab., Edwards AFB, CA (United States). Propulsion Directorate; Noel, C.J. [Ohio State Univ., Columbus, OH (United States). Dept. of Consumer and Textile Sciences; Bolf, A.G.; Ruth, P.N. [Hughes STX, Edwards AFB, CA (United States)

1996-12-31

379

Grafting of wood pulp with thermoplastic sidechains to make wood/plastic composites  

Energy Technology Data Exchange (ETDEWEB)

A method of grafting lignin-containing materials is now known which allows 1-phenylethylene or 4-methyl-2-oxy-3-oxopent-4-ene graft copolymers of wood to be quantitatively made. Graft copolymer is formed by conducting a free-radical polymerization with 1-phenylethene in nitrogen-saturated, organic or aqueous/organic solvent containing a lignin source, calcium chloride, and a hydroperoxide. Grafting changes solubility and surface properties of the wood. The lignin-containing materials grafted are unbleached wood pulps produced by chemical, thermal, and mechanical pulping. Grafting wood pulp produces a wood-reinforced, thermoplastic composite. When a particular plastic is to be blended with wood, we react the wood with the monomer used to make that plastic. This creates a hydrophobic surface of the plastic on the wood. This plastic coating can readily bond to the continuous plastic phase. The products of this grafting reaction are thermoplastic composites with dispersed, bound fibers distributed throughout the continuous phase.

Meister, J.J.; Chen, Meng Jiu [Univ. of Detroit Mercy, MI (United States)] [and others

1995-12-01

380

Compilation of radiation damage test data. Pt. 2. Thermoset and thermoplastic resins, composite materials  

International Nuclear Information System (INIS)

This catalogue summarizes radiation damage test data on thermoplastic and thermoset resins and composites. Most of them are epoxy resins used as insulator for magnet coils. Many results are also given for new engineering thermoplastics which can be used either for their electrical properties or for their mechanical properties. The materials have been irradiated either in a 60Co source, up to integrated absorbed doses between 200 kGy and a few megagrays, at dose rates of the order of 1 Gy/s, or in a nuclear reactor at dose rates of the order of 50 Gy/s, up to doses of 100 MGy. The flexural strength, the deformation and the modulus of elasticity have been measured on irradiated and non-irradiated samples, according to the recommendations of the International Electrotechnical Commissions. The results are presented in the form of tables and graphs to show the effect of the absorbed dose on the measured properties. (orig.)

1998-01-01