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
Material Designation Code for High Performance Polyethylene Piping Materials
White G. Jee, Steve D. Sandstrum, Kevin J. Kipina, May 2006
As the North American piping industry became familiar with both ASTM and ISO standards and test methods, the need to create a new material designation code for high performance polyethylene piping materials also became evident. Over the last few years, much effort has been expended to reach industry consensus on developing a new material designation code. This paper informs the reader of the actions taken in the standards development process to create a new material designation code for these materials. Also this paper addresses the performance properties of PE 4710 materials and actions taken to-date in incorporating the new material designation code in application standards.
Structure Development of Various Polyolefins in Injection Molding
Jaein Suh, James L. White, May 2006
There have been no systematic comparison studies of structures in injection moldings of the various commercial polyolefins.We have investigated crystallization and orientation development in injection molding of various polyolefins, which include high density polyethylene (HDPE), isotactic polypropylene (i-PP), isotactic polybutene-1 (i-PB1) and isotactic poly(4-methyl pentene-1) (i-P4MP1). We used both volumetric injection speed and injection pressure control as the main processing parameters with varying packing pressure and thermal condition based on injection melt and mold temperatures, similarly related to the crystalline melting points.The effort to take into account of these variations on structure development was combined with considerations of crystallization kinetics and rheological properties of raw materials.
Filament-Like Polyaniline-Polypropylene Based Electro-Conductive Composites
Ricardo H. Cruz-Estrada, Carlos V. Cupul-Manzano, Luis M. Rangel-Rodríguez, Alejandra Caballero-Can, May 2006
The effect caused by adding a polyaniline (PANI) complex (PANICX) on the electrical conductivity and microstructure of (PANICX)-polypropylene (PP) filamentlike composites with contents ranging from 1 to 50 wt.% of PANICX was studied. The composites were produced following an in-situ deformation process using a laboratory single-screw extruder and a capillary die. The microstructure was analysed using optical and scanning electron microscopy techniques. The conductivity was calculated using a Keithley electrometer. The variation of the composites conductivity with respect to PANICX content was observed to be characteristic of a percolating system. The electro-conducting phase was deformed into elongated structures embedded in the bulk of the PP and preferentially oriented in the extrusion direction.
Micro and Nano Scale Solid-State PEI Foams
Pavee Chatchaisucha, Vipin Kumar, May 2006
Polyetherimide by General Electric ( ULTEM 1000) was foamed by the solid-state process using CO2 in the subcritical range. At 5 MPa approximately 10 % CO2 by weight is dissolved in PEI. The rate of diffusion in 1.5 mm thick specimens changed when the gas pressure was lowered to 1 MPa , indicating that in this range of pressures the diffusion rate is dependent of gas concentration. Microcellular structures in PEI were obtained, with density reductions up to 45%. Nano-cellular foams, with cells in the 50-100 nm range, and with cell densities exceeding 1014 cells/cm3 were produced at 5 MPa gas saturation.
Bulk Polymerization of Methyl Methacrylate in a Kneader Reactor
P.-A. Fleury, May 2006
The bulk free radical polymerization of methyl methacrylate (MMA) or the bulk free radical copolymerization of MMA based monomer recipes face a gel effect (Trommsdorff’s effect) and exothermicity. The kneader reactor offers a perfect combination of surface renewal and evaporative cooling to control temperature at high conversion (85 to 95%).This type of reactor can be tested batch-wise to optimize the recipe, such as concentrations of initiator and of chain transfer agent. A simulation program was correlated to experimental batch data to determine the optimum concentrations of initiator and of chain transfer agent to target a given molecular weight.
Iso-Strain Force-Temperature Test (IFTT) - Probing Transitions and Stress and Thermal History in Polymeric Materials
YuanQiao Rao, R.J. Farris, May 2006
A new thermal-mechanical test method, Isostrain Force-Temperature Test (IFTT) is proposed in this paper to study the thermal behavior of polymeric materials. This method was utilized to investigate thermal properties of different forms of polymeric materials with inherent anisotropy, such as fibers and films. A variety of polymeric materials were examined. The examined materials include fibers of Kevlar®, and Spectra®, and films of Teflon®, bisphenol A PC and PET. This study provides important thermal properties of the studied materials including sub-Tg transitions or relaxations, glass transition, melting, and the stress and thermal history they experienced. Some information, which is difficult to probe using other thermal characterization methods, was disclosed for the first time.
Clay-Gelatin Nanocomposites of Improved Properties
YuanQiao Rao, May 2006
Transparent clay-gelatin nanocomposite films were made through solution processing. These films exhibit enhanced physical performance. The Young’s modulus of the composite film was 8.3 GPa, almost 3 times that of gelatin alone, by dispersing only 10 wt% of one type of montmorillonite clay into the nano-sized phase in the gelatin. With the addition of the clay nanoparticles, the melting point of the gelatin increases and the crystallinity decreases.The property enhancements of gelatin are affected by the dispersion of particles (i.e., intercalation and exfoliation), particle properties (i.e., particle aspect ratio), and particle alignment, as studied by XRD and TEM.
An Empirical Model for Melting in Co-Rotating Twin Screw Extruder
Swapnil C. Garge, Babatunde A. Ogunnaike, Mark D. Wetzel, May 2006
In extrusion processes, melting strongly influences the development of product end-use properties such as tensile strength. For effective monitoring and control of these properties, it is essential to describe the melting process quantitatively. Obtaining a high-fidelity quantitative description of the melting process, however, remains a challenging problem. This paper proposes and employs an empirical modeling approach (similar to the identification" of dynamic systems from input/output data) to model the melting process. The recently developed "pulse perturbation technique" is used to generate the input/output data. Each parameter of the identified model can be associated with a distinct melting mechanism thus providing valuable quantitative insights into the melting process. Based on the melting data presented in [1] the model is used to analyze the effect of extruder operating conditions on the melting of semi-crystalline amorphous and rubbery polymers."
Coupled Filling and Cooling Analysis for Injection Molding
Changyu Shen, Wei Cao, May 2006
Conventional analysis such as MOLDFLOW divides the injection molding process into two different stages: filling and cooling. Filling analysis assumes both the cavity and core temperatures keeping constants during filling stage, while cooling analysis assumes the part temperatures in anywhere being constants. In this study, the temperatures between mold and part are assumed unknown and determined by solving both polymer and mold thermal problems. After ejection, the mold temperatures, inheriting from the last cycle, are memorized and used as the initial values for next cycle simulation. To keep the geometrical information consistency, both the part and mold are represented by solid models. The dual domains and conventional Galerkin methods are employed to solve the filling and cooling problems respectively. The coupled method can simulate the transient and more complicate thermal problems.
Unique Atmospheric Plasma Surface Pre-Treatment Approach for Improving Adhesion
Rory A. Wolf, May 2006
Three dimensional parts comprised of polyolefins such as polypropylene have low levels of polar functional groups on the surface and have poor wettability and adhesion properties, making it difficult to apply other functional layers such as dyes, inks, adhesives and coatings. To enhance surface polarity, surface treatments such as flame, corona or plasma can be applied to improve wettability and adhesion. Plasma can specifically be used as a preparatory treatment for the photografting approach recommended in this paper to achieve high stability in treatment and permanent changes to the surface.
Weldability of Bio-Renewable Ultrasonic Exfoliated Nanocomposites
Maria Vlad, Greg Harmon, David Grewell, Avraham Benatar, May 2006
In this work the weldability of bio-renewable nanocomposites was studied. Soybean proteins were denatured in a glycerin solvent and plasticized with a screw extruder. The glycerin contained clay platelets that were exfoliated with high power ultarsonics (2.2 kW @ 20 kHz). Various levels of exposure to the ultrasonic energy were used to exfoliate the clay platelets resulting in nanocomposites with various levels of exfoliation. It was also seen that these materials were not effectively welded with hot plate welding; however, success was found with vibration welding where significant material pullout was seen at the faying surfaces after tensile testing.
Beam Shaping with Spatial Modulators for Laser Micro-Welding of Plastics
David Grewell, Avraham Benatar, May 2006
This paper reviews the use of diffractive optics for beam shaping of high-power lasers (100 W) for micro-welding of plastics. By using Fourier transformations on twodimensional complex arrays, spatial domain images were transformed into phase domain images. These images were then used to produce a mask for the microlithography etching of a glass diffractive optical element (DE). An 80 W fiber laser with a wavelength of 1084 nm was coupled in air to the lens to shape the beam into predetermined patterns. These patterns were then reduced with standard optics to a desired size. The images were focused at the faying surface of two plastic components in a through-transmission weld configuration. Weld quality was assessed based on fidelity, burst pressure and consistency. The resulting welds were able to support burst pressures as high as 0.6 MPa. In addition weld features as small as 300 ?m were also produced.
Coupled Temperature, Diffusion and Squeeze Flow Model for Interfacial Healing Predictions
David Grewell, Avraham Benatar, May 2006
This paper reviews work done to determine weld strength as a function of temperature history fields at the faying surfaces of welds. In order to simplify the resulting models, isothermal conditions were assumed by welding relatively thin films with impulse welding. Furthermore, the weld geometry was clearly defined by accurate placement of an overlap weld geometry. It was found that healing of the weld can be better defined as a function of time and temperature instead of temperature alone, as historically done. By combining squeeze flow of asperity peaks and reptilian diffusion models into one model, it was shown that by using an Arrhenius Equation as a function of temperature and time one can accurately predict weld strength and degree of healing.
Multi Physical Coupled Model; Predictions of Healing with Microwelding of Plastics
David Grewell, Avraham Benatar, May 2006
This paper reviews a coupled temperature, molecular diffusion and squeeze flow model that was used to predict the quality and size of micro-welds in plastics. Weld size and quality predictions that were based on previously presented standard heat source models models and temperature fields, were compared to experimental results. In this case, microwelds as small as 11 ?m in width were produced with through transmission infrared welding. It was found that the predictions were in very good agreement with the experimental results. The model was able to predict weld size without the need for defining a temperature range as previously reported. This model was then further developed to predict the theoretical limit of weld size based on heat source spatial relationship. It is predicted that sub-micron welds are achievable.
Physical Properties of Poly(Ethylene Succinate-Co-Trimethylene Succinate)s
Chi He Chen, Wei-Che Chang, Chia-Jung Tsai, Ming Chen, May 2006
Poly(ethylene succinate), poly(trimethylene succinate) and a series of poly(ES-co-TS)s were synthesized through a direct polycondensation process. The results of intrinsic viscosity and GPC have proven successful in preparing high molecular weight polyesters. Their thermal properties were characterized using differential scanning calorimeter. The compositions and the sequence distributions of the copolyesters were determined by analyses of 1H-NMR and 13C-NMR spectra. The sequence distributions of ES and TS units were found to be random. X-ray diffractograms were obtained for polyesters crystallized isothermally.
An Experimental Study of the Variable-Runner System
Byung-Ohk Rhee, Hyung-pil Park, Baeg-Soon Cha, Kevin Lee, May 2006
Although the family-mold has an advantage to reduce the cost, molding defects frequently occur by an excessive packing the smaller-volume cavity, especially when the two cavities have a large volumetric difference. In this study, we developed a variable-runner system for the filling balance of the cavities by changing the crosssectional area of a runner. We applied the variable-runner system to the cavities having filling imbalance, and achieved a fair filling balance. The filling balance was checked with the temperature and pressure sensors in the cavity. We also examined the influence of the injection speed to the balancing capability of the variable-runner system.
Processing Strategies for the Production of Polymer-Bonded Micro Magnets
Stefan Eimeke, Gottfried W. Ehrenstein, May 2006
As in many other technologies, the cost effective production of polymer-bonded magnets is an important factor. The volumetric ratio of sprue volume to part volume is very high due to the integration of e.g. coils for the induction of the magnetic field inside the mold. Therefore, the injection molding process of polymer-bonded magnets produces a lot of scrap material. This material has to be reprocessed to reduce the production costs of polymer-bonded magnets because the hard-magnetic fillers are very expensive. The effects of multiple reprocessing on the magnets properties are scientifically investigated.
Changes in Plastics Education due to Bologna Process in Croatia
Gordana Baric, Igor Catic, Maja Rujnic-Sokele, May 2006
Production and processing of plastics has always been a very promising industry and research field. However, for further success in this field strong educational background is necessary. Croatia signed in 2001 the Bologna declaration and in 2005 the first generation of students started their education according to the Bologna process. The implementation of the Bologna declaration has caused a lot of changes in the educational process in the fields of plastics. This paper will present the situation and the possibilities for students in the fields of plastics at four Croatian Universities (in: Zagreb (the biggest one), Osijek, Rijeka and Split) and also, research works and specific fields of interest in the Croatian educational and research institutions and the possibilities that are offered to industry experts in this area.
Process of Transition in Croatian Plastics and Rubber Industry
Gordana Baric, Igor Catic, Nedeljko Stefanic, May 2006
Business world is exposed to accelerated, revolutionary changes, driven by results of scientific research and fast technical progress, globalization process, the growing use of the Internet and the development of ebusiness. Companies are trying to adjust to these changes and at the same time they are fighting against rising costs and competition. The situation is much worse for companies from the so-called countries in transition, like Croatia. They went through a very painful process of changing the ownership, losing their markets and jobs and through process of reorganization on every level and at the same time trying to adjust their way of work to the challenges of the modern world. The situation in the Croatian plastics and rubber industry will be presented, its way of adjusting to the changing business conditions and the main organizational and managerial changes that occurred in the Croatian plastics and rubber companies during the process of transition.
Development of a Novel Micro Compounder for Polymer Blends and Nanocomposite
Dong Hak Kim, Younggon Son, May 2006
In this paper, we introduce a new type of small scale compounder. The compounder developed is for mixing of polymeric samples of 0.5 ~ 10 g. It consists of a heated cylindrical metal having two cylindrical cavities connected through a narrow channel and two cylindrical pistons, which squeeze molten polymers from one cavity to the other cavity through the narrow channel. During mixing procedure, the molten polymers flow from one cavity to the other cavity, repeatedly, and this operation generates the extensional flow in the converging and the diverging geometry. Because the compounder has mixing chamber of very simple geometry, the cleaning is very easy and the material lost is very small. We evaluated the mixing efficiency of the compounder by comparing with the commercialized small scale-mixers including a cup and rotor batch mixer, an internal batch mixer and a recirculating conical twin screw extruder. It was found that the compounder developed has many advantages over the existing small scale mixers.
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