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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Improved Solvent Stress Testing for Polycarbonate
Solvent stress testing has proven to be an effective method for identifying areas of elevated stress in parts and assemblies made from polycarbonate. Dilutions of various stress-cracking agents have been developed to quantify the levels of molded-in and/or applied stresses. Unfortunately, there has not been good correlation between the various test solutions. Calibration tests were performed for this study to develop guidelines to improve the resolution and accuracy of solvent stress testing, particularly at low stress levels.
Controlling Intra-Cavity Melt Flow and Weld Strength through New Runner Design Technology
The development of high sheared laminates are shown to have a significant effect on filling pattern. New methods are shown to manage these hotter high sheared laminates to control filling pattern and position them so as to increase weld line strength.
Molecular-Scale Reinforcement of Glassy Networks
Improvements in mechanical and thermal properties of glassy networks have been made through the use of a unique class of molecules that reinforce the network at the molecular scale, commonly referred to as fortifiers. In our studies, fortifiers are incorporated either as an additive or as a reactive monomer in the network. Each approach provides different benefits in properties. Several mechanisms of fortification are discussed and correlated to the observed improvements in properties.
Effect[GTLim1] of Slip Agent and Talc Surface Treatment on the Scratch Behavior of TPOs
A set of model TPO systems, with and without slip agent and talc surface treatment, was investigated using a linear load increase scratch test methodology. Our findings suggest that both the presence of slip agent and surface treatment of talc fillers[GTLim2] can greatly reduce scratch visibility. The underlying mechanisms are discussed.
Synthesis of Uniform ZnO Nanorods via Wet Chemistry Approach
ZnO nanords were synthesized using spherical ZnO nanoparticle precursor solution. Our unique wet chemistry approach can produce uniform ZnO nanorods at a much lower concentration than expected. We used transmission electron microscopy to characterize the rodlike shape evolution of ZnO quantum dots. The underlying mechanisms for the formation of ZnO nanorods are described and discussed.
Creep Behavior of Sisal Reinforced Starch Based Blends
Creep measurements were carried out on starch based blend reinforced with sisal short fibers. The selected matrices were MaterBi-Y (cellulose acetate) and MaterBi-Z (polycaprolactone). The studied temperatures were higher than Tg for MaterBi-Z and lower of Tg for MaterBi-Y and as expected, the behavior was different. Different models were applied and allowed the comparison with other materials.
Geometry Influence in Cavity Pressure Curves Registration
The geometric factors influence of injected pieces on the cavity pressure curves behavior during the injection process was studied. Mold cavity sensors were placing in the most critical areas in the pieces. The geometries were evaluated using an injection process simulator program. Substantial changes in the cavity pressure curves in pieces with different thickness were obtained. The shape factor is an important geometric factor that showed smaller variation in the cavity pressure registrations in pieces of small length.
Investigation of Molecular Entities Present in Maleated Polypropylene Using LSM
Maleated polypropylene (mPP) is often used as an adhesion promoter in polypropylene composites. Poly (maleic anhydride) (PMA) or oligomers of maleic anhydride are often present in maleated polypropylene, but they do not contribute to the adhesion of polypropylene to glass fiber reinforcements. PMA can be detected by confocal laser scanning microscopy.
Failure Analysis of a PEX Piping Crimp System
Premature failures have occurred in some PEX piping systems that utilized a stainless steel crimp ring to attach the PEX pipe to copper or brass fittings. Leaks in these systems were traced to a non-uniform crimping of the PEX tubing around the circumference of the fittings. Some leaks were also due to cracking of the crimp rings as a result of the crimping process and corrosion of the rings.
Flow Field Simulation of the Modular VCR in Continuous Mixer
VCR (Various clearance rotor) is a new type of continuous mixer’s modular rotor. The flow field of different configurations flow field of VCR has been simulated in this paper. According to the simulation result, the pressure, velocity and viscosity field are obtained. The average shear stress, shear rate and shear degree in deferent configurations are calculated by post-process program. Meanwhile, the mixing ability of different configurations flow field is compared.
The Effect of Process Conditions on Part Quality in Microinjection Molding
Micromolded parts produced using a range of injection velocities, mold temperatures, melt temperatures, and hold conditions were examined for part quality. Part dimensions were measured using an optical comparator and residual stresses were evaluated under polarized light. Results are discussed in terms of the material properties and processing conditions.
Statistical Approach to Evaluate Composite Damage (Design of Experiment and Evaluation)
The objective of this research is to develop a methodology for combined mechanical and thermal synergistic test for M40J/PMR-II-50 [90/0]s, a uni-tape composite material; and its analysis by using a statistical approach. Four different controlled factors (mechanical strain, temperature range of thermal cycling, number of thermal cycles, and heating rate), which degrade the composite, are evaluated in terms of both primary effects and interaction effects quantitatively.
A Study of Micro Injection Molding Optical Fiber Ferrules
This study focused on plastic micro injection molding optical fiber ferrules. Each ferrule has a through hole in the center. The inner diameter is 125±1?m. How to keep the micro core pin at the center becomes a critical issue. A guiding mechanism is introduced to reduce the chance of pin’s mis-alignment and increase life time. The design concept of presented guiding mechanism is also suitable for molding micro tubes, especially for high aspect ratio cases.
Properties of Injection Molded Amorphous Polymer for Punching
Deformation and crack-formation of holes during punching were investigated for injection molded polystyrene (PS) and polycarbonate (PC). Amount of deformation for both polymers increased with increasing punching temperature and with decreasing punching speed. The extent of deformation for both polymers were especially large when punching was conducted at temperatures above the glass transition temperature (Tg) of the polymers. For PS, two types of cracks appeared. However, only one type of crack appeared for PC.
Monte Carlo Modelling of LDPE on a Molecular Level; Relating Molecular Structure to Polymer Properties
Although LDPE is amongst the oldest polymers, it is also the polymer with one of the most complex molecular structures. Using a Monte Carlo method a model has been developed with which it is possible to calculate the detailed structure of each and every single molecule. The molecular characteristics have been related to analytical methods like GPC, NMR and DMS. Moreover the effects of the molecular structure on the polymer properties have been studied. The model has proven to be a valuable tool in product and process development.
Improvement of Mold Design: A New Method Based on Contradictions
Designing injection molds is of a critical issue in injection processing. In order to improve its design, we propose to focus on technical problems. We built and tested a design procedure based on technical problems mold design has to cope with. Using this procedure, design process duration is reduced; the mold cost and part quality might be improved.
The Role of Numerical Injection Molding Simulation in Predicting Mechanical Properties
Research objective is to establish manufacturing-related design rules and procedures for engineering design of injection molded thermoplastics parts, and to investigate application of novel materials to support development of design for sustainability. Outputs of numerical injection molding simulations have been compared with tensile and tensile-impact test results for different geometry-material combinations. Combination with simulation results on thick-walled parts reported earlier has led to a systematic with predictive capability of simulation outputs for differences in mechanical performance.
Vibration Welding Non-Planar Surfaces
This study examines the vibration welding of mating plates whose faying surface lies in two distinct planes. Plates containing both ‘horizontal’ and ‘angled’ surfaces were injection molded using a glass-fiber-reinforced nylon 6. These plates were then vibration welded to create a butt-welded assembly containing two non-parallel weldlines. The tensile weldline strengths were measured at different locations along the weld. Weld pressure, vibration direction with respect to the plate axis and the geometry of the ‘angled’ section were all observed to have significant effects on weld strength.
Molecular Reinforced Nano-Silicate Composites
It is well established that physical interactions at the polymer/reinforcement interface have a significant influence on the bulk response in nanocomposites. This paper presents results from studies where both the physical and chemical interactions at the interface are altered and related to the bulk mechanical properties of the nanocomposite. The results show that for optimum performance, both types of interactions must be considered.
Process Monitoring and Quality Prediction: A Task for the Entire Process Chain
Rising quality requirements and complexity mean that e.g. an injection molding machine can no longer be observed in isolation. It is becoming increasingly important to view the process chain in its entirety, starting with the material properties and proceeding via plastification, mold filling and cooling, right through to the downstream processes such as refinement and coating, or joining techniques. From this viewpoint for online process control, techniques are necessary that take into account every step of the production line.
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