SPE Library
The SPE Library contains thousands of papers, presentations, journal briefs and recorded webinars from the best minds in the Plastics Industry. Spanning almost two decades, this collection of published research and development work in polymer science and plastics technology is a wealth of knowledge and information for anyone involved in plastics.
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Conference Proceedings
Effect of Crystallization Conditions on Spherulitic Texture and Tensile Properties of sPS/PPO Blends
G. Dutt, K.M. Kit, May 2001
Syndiotactic polystyrene (sPS) and poly(phenylene oxide) (PPO) blends, miscible in melt state, were crystallized from melt as well as quenched state at different temperatures. The effect of processing conditions on spherulitic texture, ultimate tensile properties and the mode of fracture was studied. The study suggests that by varying composition and processing conditions in melt miscible blends it is possible to control amorphous domain sizes, which is critical in achieving better mechanical properties
CPI In-Line Compounding Systems
Marvin J. Voelker, Charles D. Weber, May 2001
Composite Products, Inc. has commercialized in-line compounding technology to produce long fiber thermoplastic composites. Turnkey systems continuously compound thermoplastic resin with reinforcements ie. ½ inch chopped glass, carbon or natural fibers to produce finished composites with outstanding toughness. The separation of thermoplastic melt processing and the introduction of glass is key to fiber length retention. The patented technology provides molders the ability to maintain the highest level of physical properties while molding appearance parts. or strongly reduce
Blends of Recycled Polyethylenes and Metallocene Impact Modifiers for Rotational Molding
E. Takács, M. Kontopoulou, J. Vlachopoulos, E. Voldner, K. Nichols, May 2001
This paper describes the development of blends of recycled polyethylenes suitable for rotational molding. The blends consist of recycled post-industrial polyethylene resins and polyolefin plastomer impact modifiers, produced by single-site (metallocene) catalysts. The rheological properties of the blends were found to be favorable for rotational molding. Rotomolded parts provided satisfactory low temperature impact strength and good tensile properties.
Toughening Mechanisms in Fiber-Containing Impact Modified Polymers
Guoxin Sui, Shing-Chung Wong, Chee-Yoon Yue, May 2001
An attempt was made to separate the toughening arising from the presence of fiber and that from the toughened matrix using the essential work of fracture. Toughening mechanisms with fiber inclusions were found to be associated with fiber bridging, debonding and pull-out. It was concluded that such fiber toughening would yield a flat curve when the specific total fracture work was plotted against the ligament length. The technique was able to produce fruitful information regarding design for property synergism in impact modified nylon 6,6.
Prediction of Transient Material Functions of PP Resins Using the Multi-Mode PTT Molecular Network Model
Jaime Bonilla Ríos, Rodolfo Mier Martínez, May 2001
The transient rheological material functions [?(t,?),N1(t,?),?e(t,?) ] of three PP resins are predicted using the multi-mode Phan-Thien and Tanner (PTT) molecular network model. The study also includes the standard quality properties (MFI, XSP, GPC, and DSC) of the resins. The model was coded in C-language, validated with published data (Phan-Thien, 1978) and then used for the prediction of transient material functions. The predictions are in good agreement with the resins' rheological data.
An Experimental Comparison of the Improved Mixing Obtained from a New Barrier Screw Design
Kevin R. Slusarz, Michael R. Thompson, John P. Christiano, May 2001
A comprehensive study looking at both distributive and dispersive mixing for a new screw design was done on a single screw extruder. The findings showed an improvement in mixing performance with this new style barrier screw over a conventional barrier screw design. Mixing performance was evaluated by means of microscopic analysis. To better quantify mixing three different systems will be studied; distribution of a pigment, distribution of an inorganic filler, and dispersion of a minor component in an immiscible blend.
Probing Local Chemical Interactions and Bond Energies with AFM
James D. Batteas, Chang Xu, James Helt, Marcus K. Weldon, May 2001
Atomic force microscopy has been utilized to examine molecular interactions of native and OTE modified silica surfaces under aqueous conditions. For native silica, depending on pH, the measured adhesion consists of convolutions of different interactions, including hydrogen bonding, anionic hydrogen bonding and covalent bond breaking. Modification with OTE allows for hydrophobic interactions to be probed, and time dependent adhesion results suggest the possibility of probing molecular reorganization within the contacts.
Polymer Blend Morphology by Dynamic AFM
Andy H. Tsou, May 2001
The reduction in lateral forces during scanning allows the tapping-mode AFM to be an extremely useful tool for evaluating the morphology of polymer blends. Without staining or etching, rubber/plastic domains and fillers in cryo-faced polymer blends can be obtained with strong contrast. Subsequent image processing and measurement of AFM micrographs can provide quantitative structural parameters in blends. Filler partition in polymer blends, compatibility and interfacial tensions between polymers, and filler and phase networking can be measured.
Chemical Imaging with near Filled Scanning Optical Microscopy
Stephan J. Stranick, D. Bruce Chase, Chris A. Michaels, May 2001
The ability to measure chemical bond changes on the nanometer scale is of critical importance for the characterization of catalytic processes, catalytic materials, and surfaces relevant to materials and biological problems. Our goal has been to develop a technique for in-situ, non-destructive measurements of site-specific chemistry on the nanometer scale. The strategy for realizing this goal involves coupling the high spatial resolution of near-field scanning optical microscopy (NSOM) with the chemical specificity of vibrational spectroscopy.
In-Mold Decorating of Plastic Parts
Jordan I. Rotheiser, May 2001
In-mold decorating is a technique with a long history. However, recent developments have created new opportunities for designers. This paper discusses these techniques and how they are applied to plastics.
Comparison of Conventional High-Flow HDPE and Single-Site High-Flow HDPE Blends
T.J. Schwab, W.G. Todd, May 2001
Polyethylene (PE) injection molded rigid containers are widely used for food packaging, especially for frozen and refrigerated food applications. Due to the cold end-use environment, molders of these containers are constantly looking to improve impact performance while maintaining other physical properties. This work compares molded part physical properties of conventional high-flow HDPE products to those obtained with single-site HDPE products and blends of conventional high-flow HDPE with single-site HDPE or metallocene PE.
COF of LLDPE Film at Low Loadings of Erucamide
María X. Ramírez, Douglas E. Hirt, Nate Miranda, May 2001
The relationship between surface concentration and COF of LLDPE films has been studied for the slip agent erucamide [1]. This research continues this study, relating the film's additive surface concentration to its bulk loading. Low bulk loadings ranging from 100 ppm to 1000 ppm were investigated. The surface concentration was measured using surface washing and the bulk loading was quantified using microwave extraction. Results indicate the COF at a given surface concentration to be path-independent, as was hypothesized in our previous study [1].
Migration of Fluorinated Additives to HDPE Film Surfaces
Keisha B. Walters, Douglas E. Hirt, May 2001
The surface concentration of fluorinated additives has been investigated in high density polyethylene (HDPE) films. These additives have been used as processing aids and are presently being studied as surface-property modifiers to lower the surface energy for applications where hydrophobicity is important. We have used ATR-FTIR and ESCA to characterize the composition of these modified film surfaces. Results indicate the extent of surface segregation as a function of additive molecular weight and bulk loading.
Measurement of Microstructural Variation in Blown Films
S. Cherukupalli, R. Jelen, A.A. Ogale, May 2001
A real-time study on the evolution of molecular structure in an isotactic polypropylene blown film (i-PP) is reported. The structural variation along the machine direction of the film has been observed with online Raman spectroscopy. Preliminary measurements indicate a variation in the intensity of 809 cm-1 peak relative to the 841 cm-1 peak as the state of the polymer changes from a melt to solid at the freeze line. This change is related to the development of crystallinity along the film line.
On the Use of Rotational Rheometry for Quality Control
Nafaa Mekhilef, David S.C. Lee, Florence Dion, May 2001
The aim of this work is to evaluate if rotational rheometry provides a more useful measurement of viscosity than capillary rheometry and melt flow index measurements in production environments. To achieve this, we compared the sensitivity of these methods for quality control in the batch production of a commercial fluorinated polymer by using statistical analysis and the ease-of-implementation criterion of each method. The utility of rotational rheometry to develop flow curves to assist blending in a batch process was also investigated.
Status of Research on Design for Mechanical Reliability of Injection Molded Plastics Products
Rolf Koster, May 2001
Various injection molded specimens and specimens from injection molded products have been tensile and tensile-impact tested to develop manufacturing-related design guidelines. Tensile strength of PS perpendicular to flow was affected by both filling-induced and packing-induced phenomena. For a nylon block copolymer the influence of test speed was shown. Cold weld line strength in PS was reduced by increased temperatures in the skins during molding. For polyester-amide and PHB the amorphous structure fraction contributed to reduced weld line strength.
Process Dynamics in Sequential Valve Gate Injection Molding - Processing Strategy and Process Control
Suk-young Shin, Nick Schott, Stephen McCarthy, May 2001
The process dynamics of sequential valve gate injection molding were investigated using multiple pressure transducers in a single cavity. System response is analyzed based on the servo valve signals and the cavity pressure profiles. The optimum process control and part quality control settings of the Sequential Valve Gate system were determined. Also, the experimental results were compared with the predicted results obtained from a simulation program.
Fracture Toughness of Co-Continuous Polycarbonate/ABS Blends
J.P.F. Inberg, L.C.E. Struik, R.J. Gaymans, May 2001
Polycarbonate/ABS blends are industrially important however very little reported on in literature. Co-continuous PC/ABS (50/50) blends were made on a twin-screw extruder and tested in notched Izod at different temperatures and different rubber content in the ABS. Ductility improved strongly with increasing rubber content in the ABS (Tbd lowered to about -40°C) with little decrease in modulus.
Numerical Simulation of Injection Molding of Semicrystalline Thermoplasti
Jianxin Guo, Kwabena A. Narh, May 2001
Injection molding process of semicrystalline plastics was simulated with a stress-induced crystallization model. Pseudo-concentration method was used to track the melt front advancement. The stress relaxation was incorporated into the model using the WFL model. Simulations were carried out under different processing condition to investigate the effect of processing parameters on the crystallinity of the final part. The simulation results reproduced most of the features reported in the literature.
Process Fingerprints for Compounding of Polymer Blends – An Industrial Prospective
Chi-Kai Shih, May 2001
A process fingerprint measurable by on-line monitoring of common process variables could aid immensely the ability of a process engineer to control the process output. The torque curve of a Brabender batch internal mixer offered many fingerprints related to the fundamental behavior the raw ingredients experienced during the mixing process. Suggestions were made how to derive fingerprints from the fundamental functions of twin screw extrusion processes.
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