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

HOW GREEN POLYMERS FIT IN YOUR BUSINESS AND WHERE THEY MAY NOT

Roger Jones, May 2011

Green polymers are being brought to market in order to capitalize on a perceived demand from environmentally conscious consumers. Plastics industry processors and users need to know, however, just what are the particular characteristics of different green polymers and which specific end use demands they fulfill? Are they broad-based products or a series of niche specialties? This paper will address the relative characteristics of current green polymers from point of view of end use market needs, and how best to meet these needs, in terms of economics, performance, and utility.

NANOSCALE INFRARED SPECTROSCOPY OF BIOPOLYMERIC MATERIAL

Michael Lo, Curtis Marcott, Isao Noda, Craig Prater, Debra Cook, Roshan Shetty, Kevin Kjoller, May 2011

Atomic Force Microscopy (AFM) and infrared (IR) spectroscopy have been combined in a single instrument capable of producing sub-micron spatial resolution IR spectra and images. This new capability enables the spectroscopic characterization of microdomain-forming polymers at levels previously impossible. Films of poly(3-hydroxybutyrate-co-3-hydroxyheanoate) were solution cast on ZnSe prisms. Dramatic differences in the IR spectra are observed in the 1200-1300 cm-1 range as a function of position on a spatial scale of less than one micron. This spectral region is particularly sensitive to the polymer crystallinity, enabling the identification of crystalline and amorphous domains within a single spherulite of this copolymer.

RHEOLOGICAL EFFECTS ON FOAM PROCESSING IN ROTATIONAL MOLDING

Maryann Emami, John Vlachopoulos, Elizabeth Takacs, Michael Thompson, May 2011

Rheological properties of several polypropylene polymers were measured and the foam processing of these materials using chemical blowing agent was studied. Foaming was carried out in monolayer and skin-foam layer moldings. The uniaxial extensional viscosity was quantified and the foam characterized based on bulk density, bubble size, and bubble concentration. It was found that the foam processing window is determined and bounded by melt viscosity and melt elasticity. Melt strength and strain-hardening can substantially improve the foaming performance and play significant role in determining the developed morphological structure.

STUDY ON THE PROCESS PARAMETERS TO IMPROVE STRENGTH OF WPC PREPARED BY A NOVEL COMPRESSION MOLDING SYSTEM

Rubyet Islam, May 2011

It was found that compression molded Wood Plastic Composites (WPC) show lower strength than the extruded WPC which could be due to lower net alignment of the reinforcing fibers and lower inter-diffusion and alignment of the polymer chains due to the smaller net flow of material during processing. To test this hypothesis, a new compression molding system was developed where materials were forced to flow in one direction. Comparative strength studies of WPC, prepared by this novel compression molding system, have been presented at varying speed and temperature of die-press. The initials results seem to validate our hypothesis.

FILLER RE-AGGREGATION AND NETWORK FORMATION TIME SCALE IN EXTRUDED HIGH DENSITY POLYETHYLENE / MULTI-WALLED CARBON NANOTUBE COMPOSITES

Castillo Yepez, Brian Grady, Daniel Resasco, May 2011

Multi-walled carbon nanotube (MWNT) / high density polyethylene (HDPE) composites with varying amounts of carbon nanotubes were investigated and the effect of MWNT weight fraction on their electrical conductivity, crystallinity and mechanical properties is presented here. Samples were prepared by melt dilution of a HDPE masterbatch containing 20.2 wt% MWNT with varying amounts of neat HDPE. The effect of extrusion processing on the formation of an electrically conductive MWNT network in extruded samples was assessed by the addition of a low-shear annealing zone (shear rate 1-10 s-1) before final extrusion through a die and it is also discussed here.

INVESTIGATION OF THE RELATIONSHIP BETWEEN CELLULAR AND MECHANICAL PROPERTIES OF INJECTION FOAM MOLDED POLYMER COMPOSITES

Peter Jung, Chul B. Park, May 2011

Microcellular injection foam molding technology can bring a number of advantages to the existing conventional injection molded products such as lower density, material cost reduction, reduction of residual stress, better dimensional stability, reduction of cycle time, and better dispersion of fillers. However, the technology has not been fully employed yet, especially in the automotive sector, because injection foam molded parts, in general, experience a decrease in mechanical strengths. Therefore, this research studies the relationship between cellular and mechanical properties of the two common polymer composites in the automotive industry, which are glass-fiber reinforced plastics (GFRP) and wood-fiber polymer composites (WPC).

THERMOPLASTIC STARCH BLENDS WITH POLYPROPYLENE

Gregory Anderson, May 2011

Polypropylene blends with thermoplastic starch (TPS) have demonstrated significant potential in the bioplastics field. The polymers are improved by achieving higher biocontent and lower green house gas emissions. The TPS is finely dispersed by means of a tandem extruder with plasticizer, water, heat, and shear, and then melt blended with the polymer to produce a co-continuous morphology of TPS and polymer. TPS blends produced in this method lead to improved retention of physical properties over conventional methods. The TPS method is presented as well as morphology, GHG emissions, and properties.

OXIDATIVE STABILITY OF VITAMIN E INFUSED, HIGHLY CROSSLINKED POLYETHYLENE FOR ORTHOPEDIC APPLICATIONS

Jordan Freedman, May 2011

In this paper, highly crosslinked and vitamin E infused (VITE) ultra-high molecular weight polyethylene is evaluated for mechanical properties, oxidation resistance, and wear. Testing included small punch mechanical properties, impact strength, a fatigue study, and knee wear simulator testing. The VITE material showed no evidence of oxidation and no decrease in the mechanical properties with accelerated aging. The VITE material showed an 86% reduction in wear over the control. The combination of crosslinking and vitamin E infusion produced a polyethylene material with improved wear properties and superior oxidation resistance suitable for use in orthopedic applications.

THERMOSET NANOCOMPOSITES FROM EPOXIDIZED LINSEED OIL FOR STRUCTURAL APPLICATIONS

Khozema Jafferji, Daniel Schmidt, Emmanuelle Reynaud, May 2011

In this study, a bio-based epoxy thermoset was made from highly functional epoxidized linseed oil (ELO) using a polyethyleneimine (PEI) crosslinking agent. Following optimization of cure conditions and the stoichiometric ratio of ELO to PEI, the compatibility of this system with several commercial montmorillonite and hydrotalcite layered nanofillers was studied. The hydrotalcites were observed to enhance the homogeneity of the ELO-PEI system, whereas the montmorillonites showed settling and produced inhomogeneous materials in all cases.

Application of Variational Asymptotical Method for Unit Cell Homogenization (VAMUCH) in the Prediction of Mechanical Properties for Microcellular Plastics

Emily Yu, Jun Peng, Lih-Sheng Turng, May 2011

This study presents the application of Variational Asymptotical Method for Unit Cell Homogenization (VAMUCH) with a three-dimensional unit cell (UC) structure and finite element analysis for analyzing and predicting the effective elastic properties of microcellular injection molded plastics. A series of injection molded plastic samples with microcellular foamed structures were produced and their mechanical properties were compared with predicted values. The results show that for most material samples, the numerical prediction is in fairly good agreement with the experimental results, which suggests the applicability and reliability of VAMUCH in analyzing the mechanical properties of porous materials.

PRELIMINARY RESULTS IN RHEOLOGICALLY OBTAINING MODEL PARAMETERS FOR THE PURPOSE OF PREDICTING THE ORIENTATION OF CONCENTRATED LONG GLASS FIBERS IN PROCESSING FLOWS

Kevin Ortman, Donald Baird, Peter Wapperom, Jeffrey Giacomin, May 2011

The purpose of this research is to understand the transient fiber orientation of long glass fiber (> 1mm) reinforced polypropylene, in a well-defined simple shear flow (using a sliding plate), by determining unambiguous model parameters from rheological experiments, and to ultimately predict fiber orientation in complex processing flows. Two fiber orientation models were investigated. One model, the Folgar-Tucker model, has been particularly useful for short glass fiber systems and was used in this paper to assess its performance with long glass fibers. A second fiber orientation model, one that accounts for the flexibility of long fibers, was also investigated.

RHEOLOGICAL CHARACTERIZATION OF POLYPROPYLENE MIXED WITH SPECIALLY MODIFIED CALCIUM CARBONATE

John Suwardie, Peng Wang, Zheng Qian, Costas Gogos, May 2011

The rheological properties of polypropylene filled with specially coated calcium carbonate were investigated in this study. CaCO3 fillers were coated in order to further improve the mechanical and flow properties of the filled polymer. A fluid energy mill (FEM) was used to simultaneously mill and coat the calcium carbonate particles. Both rotational and capillary rheometers were utilized to study the rheological impact of the coated particles. The rheological properties of the specially coated particles were compared with non-coated particles at similar concentration. Shear viscosity, dynamic viscosity and also melt flow index were determined at three different temperatures.

AGING DEPENDENT SLIP AGENT SURFACE MORPHOLOGY OF LLDPE FILMS

Jiazing Chen, Hoang Pham, Nilesh Savargaonkar, Shouren Ge, May 2011

The ability to maintain stability of coefficient of friction (COF) for low density polyethylene (PE) films has been a persisting issue for the flexible food and specialty packaging industry. We conducted a systematic study monitoring the change on slip agent coverage and morphology change on PE film surfaces including films aged at room temperature and at elevated temperatures. We found significant change in slip agent morphology on the film surface over long aging time at room temperature. This paper describes our investigation on erucamide, a slip agent, surface coverage and its morphology changes with respect to aging time and temperatures.

RHEOLOGICAL CHARACTERIZATION OF POLYCARBONATE RESINS AND ITS APPLICATIONS

Vitaly Benkin, May 2011

We show results of rheological testing of polycarbonate resind and its applications. Rheological characterization provides indirect measurements of materials properties, such as molar mass and molar mass distribution. Dynamic storage Gƒ?? and loss Gƒ? modulus represent elastic and viscous properties of the material. Viscosity curves give information about materials behavior under different temperatures and shear rates. Dynamic mudulus and zero shear viscosity can be used as qualitative parameters to characterize and distinguish different materials, and to predict materials performance. Rheological data can be used for process optimization and quality control.

ORDERING KINETICS OF BLOCK COPOLYMER SOLUTIONS DURING SOLVENT REMOVAL

Michael Heinzer, Sangil Han, Stephen Martin, Donald Baird, May 2011

The ordering kinetics of block copolymers in solution are studied during a solvent removal process. The kinetics of styrenic block copolymers in a neutral solvent, toluene, are tracked at various concentrations along a drying path to determine the effect of concentration on phase separation. The ordering process is modeled with the Avrami equation. Small angle X-ray scattering has been used to determine that the structures developing during solvent removal are cylinders. Scattering data also indicates that the concentrations studied by the rheology experiments are limited by the conditions under which samples are dried.

MODELING AVERAGE CAVITY TEMPERATURE USING ARTIFICIAL NEURAL NETWORKS

Scott Everett, Jose Hernandez, Rickey Dubay, May 2011

Average cavity temperature has been shown to be a suitable control variable in obtaining repeatable part quality. Existing control schemes for average cavity temperature use on-line and off-line identification techniques to formulate system models. These models are often linearized about a specific operating region and introduce inaccuracies in control due to process nonlinearities. This work presents an online artificial neural network black-box system identification routine to model the nonlinear dynamics of the average cavity temperature with respect to mold and process conditions.

LOW-DENSITY POLYETHYLENE COMPOSITES FILLED WITH CERAMIC FILLERS FOR ELECTRONIC PACKAGING APPLICATIONS

Ellen Chan, Siu Ning Sunny Leung, M. Omer Khan, Hani Naguib, Francis Dawson, Vincent Adinkrah, Laszlo Lakatos-Howard, May 2011

This study details the fabrication of linear low-density polythene (LLDPE)-based composite materials containing silicon carbide (SiC) and boron nitride (BN) filler particles. The composites were created by using a twin-screw compounder, and evaluated based on their morphology, as well as their thermal, electrical, and mechanical properties. Overall, the addition of ceramic fillers increased the thermal conductivity of the composites, without compromising the electrical resistivity, which is desirable for electronic packaging and heat management components in microelectronics.

A STUDY ON EFFECTS OF VARIOUS PARAMETERS ON COLOURS DURING COMPOUNDING OF PLASTICS

Musharaf Rabbani, Jamal Alsadi, Ghaus Rizvi, Shahid Ahmed, Daniel Ross, May 2011

The historical production data of SABIC IP, Cobourg, was used to determine effects on colours of compounded plastics, of using extruders of different configurations, incorporating minute variations in pigment compositions and using different grades of resins. The colours had been measured in terms of CIE L*,a*,b* values using a spectrophotometer. The measured L*,a*,b* values were then analyzed and compared to the target values using statistical methods. The differences in the observed trends are discussed.

THE MULTIFUNCTIONAL CHARACTERISTICS OF CARBONACEOUS FILLER-REINFORCED POLY(PHENYLENE SULFIDE) COMPOSITES

Muhammad Omer Khan, Siu Ning Sunny Leung, Ellen Chan, Hani Naguib, Francis Dawson, Vincent Adinkrah, Laszlo Lakatos-Howard, May 2011

Poly(phenylene sulfide) (PPS) composites, reinforced by carbon fibers (CFs) and multiwall carbon nanotubes (MWCNTs), were fabricated through melt compounding. Their thermal, electrical, and mechanical properties were systematically studied as functions of filler contents and properties. The electrical percolation thresholds for CFs and MWCNTs were identified; however, the thermal percolation thresholds could not be achieved. This illustrates different requirements are needed in carbonaceous filler network to promote different functional performances of the composites.

MICROCRYSTALLINE CELLULOSE COMPOSITES OF POLY(LACTIC ACID)/POLY(ETHYLENE GLYCOL) OR POLYPROPYLENE CREATED VIA SOLID-STATE SHEAR PULVERIZATION

Philip Brunner, John Torkelson, May 2011

Hybrids of poly(lactic acid) (PLA) or polypropylene (PP) with microcrystalline cellulose (MCC) were created using solid-state shear pulverization (SSSP). For the PLA composite, this was followed with melt processing (MP) with added polyethylene glycol (PEG). We demonstrate a synergistic effect of MCC and PEG in enhancing the crystallization kinetics of PLA. Additionally, an SSSP processed 80/20 wt% PP/MCC composite was successfully injection molded into a bottle cap, which shows excellent MCC dispersion and stiffness.