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.
Improper rebuilding of screws for injection molding plasticators can lead to screws with high wear rates and the formation of resin degradation products. Resin degradation can cause black specks and color streaks in injection molded parts, reducing the yield and profitability of an injection molding process. This paper presents two problems that occur when injection molding screws are not rebuilt properly.
A novel alternating film/foam multilayer sheet was prepared through multilayer co-extrusion. The film layer was a blend of LLDPE with poly(ethylene-octene) elastomer (POE) and the foam layer was cross-linked and foamed POE. The multilayer film/foam sheet exhibited advantaged acoustical properties. In select wavelength regions, the sound absorption coefficient of the multilayer film/foam structure improved 2-3 times compared with conventional single-layer materials.
This paper deals with the effects of barrel and screw heating in rubber extrusion particularly with regard to the throughput and the melt temperature. To determine exactly the impact of heating on throughput behavior during extrusion, experimental investigations were conducted on two rubber extruders of different sizes. In addition, numerical flow simulations were carried out for non-isothermal shear thinning melt flows, under consideration of dissipative heating in the screw channel.
Chemical modification of poly(lactic acid) (PLA) through a reactive extrusion process was performed in the presence of a free-radical initiator and multi-functional chain extenders. Batch foaming, using nitrogen as the blowing agent, was done at various temperatures to differentiate the effect of chain branching and nucleation on the cell size of reactively modified foams. Depending on the conditions very fine, sub-micron size foams were obtained in reactively modified PLA.
Many existing extruders running polyethylene (PE) resins can be optimized to operate at higher production rates and also with higher qualities by the mitigation of gels. This paper provides an assessment process where the extruder is studied for potential rate increases and quality improvements. It is recommended that such an assessment be made prior to purchasing new screws or when a line is close to becoming sold out and more product is required.
While a test method for thermoplastic pipe to determine resistance to rapid crack propagation has been standardized for nearly 20 years, very little testing of PVC for water use has been done. Test methodology and results are presented in this paper for the S4 testing for water for fused PVC manufactured to the AWWA C900 PVC pipe standard, Critical pressure, crack speed, and decompression wave speed are discussed..
Including an explanation of design of experiment (DOE) principles, this paper describes the procedures and results of a designed extrusion experiment. The goals were to understand and model the influence of key process variables (barrel zone temperatures and screw speed) on several performance indicators, such as output, pressure variation, and temperature variation. One important finding was a quadratic model of melt temperature variation, primarily as a function of screw speed and barrel zone 1 temperature.
Semiconducting insulation shield compounds with reduced adhesion to tree retardant cross-linked polyethylene (TRXLPE) are presented. Through a combination of additives comprising 5% by weight of the formulation or less, adhesion force can be reduced by 40% or more without compromising other critical properties such as volume resistivity, cure kinetics, and physical characteristics including tear strength.
ASTM Melt Flow Rate is one of the most common product specifications and is widely used by resin manufacturers and users. Small Amplitude Oscillatory Shear (SAOS), on the other hand, is the preferred rheology data for researchers. A one-to-one correlation between these two kinds of rheology data has not been observed or reported in the past. With a new approach of applying the Cox-Merz Rule, excellent estimates of ASTM melt flow rates were obtained from the SAOS data for a wide range of linear polyethylene resins.
Covering higher output rates in the production of thermoforming sheet motivated the development of a new roll-stack design. While amorphous materials like HIPS and A-PET are not sensitive to cooling parameters, the quality of sheet made of semi-crystalline polymers like PP and PE is showing a great dependency on their cooling history. In the daily production environment not only higher outputs were achieved, but improvements in quality and performance were obtained.
A DSC method was demonstrated to determine the temperature uniformity at transverse direction in BOPA annealing oven by utilizing the existence of small endothermic peak before the melting of alpha-form (221 øC) and /or gamma-form (214 øC) nylon 6 on 1st heating thermograph.
Thermoplastics are often compounded with fillers including talc, mica, calcium carbonate, and nanoclays. These materials often shorten the service life of the processing equipment. This paper describes the screw wear and the processing performance differences that commonly occur with these materials. Remediation techniques are presented.
Optical tomography (OT) is a method that allows volumetric measurements from translucent samples. It is used in medicine and the measurement principle is similar to X-ray computed tomography. Plastics samples are often translucent and are thereby viable for OT measurements. The volumetric foam structure of polymer foams can be visualized using OT.
A biorenewable thermosetting polymer was synthesized by copolymerizing acrylated epoxidized soybean oil and tung oil using a free radical polymerization method. It is found that tung oil acts as a plasticizer in acrylated epoxidized soybean oil. This article presents a simple, versatile, and environmentally friendly technique to produce thermosets with a wide range of thermo-mechanical properties.
This study is related to PET with minor amounts of polycarbonate and PE-LLD. Depending on the shearing in the melt, a minor amount of PC is fully miscible, or exists as nano domains in the PET matrix. On the other hand, PE-LLD is immiscible with PET even in a minor concentration, and it forms micron-sized domains. In a ternary blend of PET, PC (2%) and PE-LLD (3-5%), surprisingly the PC acts as a compatibiliser for the PE-LLD and reduces its domain size in the polymer matrix.
Ultrasonic sealing of thermoplastic films is growing in acceptance throughout the plastics industry, primarily within packaging applications. Reducing the amount of film required for a given application is typically what drives consideration of ultrasonic sealing. However, superior seal quality, the ability to seal through contaminants, and improved process control are becoming increasingly important factors. This document describes the expected benefits of the ultrasonic sealing of films as well as limitations to be considered.
The use of X-ray and spectroscopic methods has been essential to the development and understanding of pigments in the 20th and 21st centuries. In this presentation I will provide some examples of the more pertinent of the developments made possible by the use of these powerful tools.
Flexil? is a novel modified organosilicon based additive developed and marketed by Polymer Dynamix, LLC in South Plainfield, NJ. Flexil? provides the impact modification to glass fiber reinforced polymers. The results demonstrate that Flexil? increases the elongation and impact properties in glass reinforced polymers such as polybutylene terephthalate and polyamide.
Recent developments having a potential to produce purely polymer based, transparent barrier packaging films are reviewed. The focus of this review paper is on micro-/nano-layer enhanced barrier improvment technology. This technology allows a significant barrier property improvment by controlling crystal lamellae alignment in various barrier polymers. The critical parameters affecting crystal lamalle orientation are briefly described as well.
Continuous fibrous composite tapes of PA6/PEO were produced using a novel co-extrusion and two-dimensional multiplication technique. The process is highly versatile in that the number and composition of PA6 fibers and the geometry of the tape can be easily adjusted for various applications. The PA6 fibrous tapes were post-oriented to achieve ultrahigh mechanical properties. In comparison with commercial fibrous composite tapes, the PA6/PEO tapes made using the co-extrusion technology have improved tensile modulus, tunable tensile strength and strain at break.
Any article that is cited in another manuscript or other work is required to use the correct reference style. Below is an example of the reference style for SPE articles:
Brown, H. L. and Jones, D. H. 2016, May.
"Insert title of paper here in quotes,"
ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers
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