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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AN EXPERIMENTAL STUDIES ON THE EJECTION FORCES FOR POLYMER RESINS
The development and manufacture of the tool for injection molding is a complex task which demands highly skilled and experienced operator. This paper is to analyze the ejection force for different selected polymer resins which is having a series of surface roughness. The research was carried out on a cylinder shaped molding with variations in wall thicknesses. The result reveals that PA6 required high ejection force due to surface texture generated compared with HIPS and ABS.
STUDY ON EXTERNALLY WRAPPED COILS INDUCTION HEATING AND ITS APPLICATION ON RAPID MOLD SURFACE HEATING
The purpose of this study is to use externally wrapped coil induction heating to determine the practicality of its application in mold temperature control. A simulation was performed using the ANSYS software by the integration of both thermal and electromagnetic analysis modules. By experiment, the heating efficiency of coils in series was found to be 8.26C/s, while for parallel coils, it was 1.88C/s. Coils in series offers a much faster heating process. Both the simulation and experimental results are quite similar.
HIGH FLOW GLASS FIBER FILLED AROMATIC POLYAMIDE RESINS
Novel idea of using hyperbranched polymers - dendritic aliphatic polyesters (DAP) as flow promoters in highly glass fiber reinforced polyamides (GF-PA) system is depicted in this paper. Different concentrations and types of DAPs is employed and these are found to be effective in modifying flow from 10% to 160% with the at as low as 0.5 to 3 weight % concentration for GF-PA without affecting the enabling mechanical and thermal properties.
UV-CURE COATINGS ON PLASTICS ADVANTAGES AND APPLICATIONS
The first UV coating was introduced to US Market more then 35 years ago sometimes in the early 70th of the last century. Since then UV coatings steadily grew in North America consumption from modest 1.3M gallons per year to 290M gal of projected sales in 2010. Growth in UV coating started with Inks and Overprint Varnishes following the Wood coatings and finally with advancement in technology for radiation cure coating for metals and plastics started to emerge into the market place.
ONE DIMENSIONAL MELTING IN SINGLE-SCREW EXTRUDERS
For special operating conditions and resins, the melting process for single-screw extruders can occur via a very non-traditional mechanism. For this process, melting occurs almost exclusively at the solid bed-melt film interface between the solid bed and the barrel wall. The newly molten material then infiltrates the solid bed such that a melt pool does not form on the pushing side of the channel. This paper describes the mechanism and provides a model for the melting process.
FIELD FAILURE MECHANISMS IN HDPE POTABLE WATER PIPE
High density polyethylene (HDPE) pipe has been widely used in potable water water applications for several decades. In some locales HDPE pipes have experienced premature failures that have been traced back to a variety of causes. A review of the failure mechanisms observed will be presented along with a forensic analysis of some field failures.
LIGHTWEIGHT CONSTRUCTION POTENTIAL IN THE POWERTRAIN - TRANSMISSION HOUSING PRODUCED BY THE PLASTIC/METAL HYBRID METHOD
In the automotive industry, the use of plastics in the powertrain is essential for lightweight construction and thus for meeting CO2 emission targets. The present technology of light alloy die-casting used to manufacture transmission housings offers little further savings potential. Additional weight savings can, however, be achieved by using a hybrid process (metal/plastic composite). Various levels of this material hybridisation" will be examined here."
COMPATIBILITY OF COATED FABRICS USED IN COLLAPSIBLE FUEL STORAGE TANKS WITH BIODIESEL FUELS
We evaluate the effect of three different biofuels on the properties of three currently used storage container materials. These consist of two urethane coated fabrics and one nitrile coated fabric. In all of our experiments, standard diesel fuel was used for comparison and the resulting permeation rates were found to be greater than the biofuels evaluated in this study.
ULTRASONIC CUTTING OF BIODEGRADABLE POLYLACTIC ACID (PLA) FILMS
Ultrasonic cutting systems are employed with materials that are difficult to cut with standard mechanical systems. The cutting knife/edge typically vibrates at a frequency of 20-60 kHz, heating the substrate during the cutting and simultaneously sealing the cut edges. Polylactic acid (PLA), a biodegradable thermoplastic material derived from starch and sugar, is relatively brittle compared to polyethylene terephthalate (PET), which has similar mechanical properties. This brittleness is problematic during mechanical cutting, which produces micro-cracks that further embrittle the material.
FAN GATE DESIGN TO IMPROVE PACKING CONTROL
A study was performed to determine the effects that three different fan gate designs had in thoroughly packing out an injection molded five-sided box with ribs. Part weight and the identification of sinks and voids on the part will be the means of interpreting the effectiveness of each gate. The materials that were used to conduct the experiment were PC, ABS, POM, and PP.
PHOTODEGRADATION OF POLYPROPYLENES WITH CLARIFYING AGENT
The work compared the effect of ñ-nucleating/clarifying agent based on 1,3;2,4-bis(3,4-dimethylbenzylidene)sorbitol on the photodegradation in two polypropylenes. One of them was nucleated directly by producer while the second in the laboratory. For comparison, neat PP was studied as well. The samples were irradiated by UV-light and then examined using several methods. The results showed that the addition of ñ-nucleating agent influenced only slightly the process of photodegradation. However, significant differences in structure among the materials were observed.
IMPROVED DIALYSIS TECHNIQUE FOR CORE-SHELL PULLULAN-POLYCAPROLACTONE (PCL) NANOSPHERES LOADED WITH HYDROPHOBIC CIPROFLOXACIN
Drug delivery vehicles in the form of nanospheres improve solubility, bioavailability and biodistribution of many pharmaceutical drugs. However, low encapsulation efficiency is a limitation that currently challenges many drug carriers. The dialysis method can be used as a technique to address this problem and enhance the apparent purity and consistency of the nanospheres being prepared. This research introduces a dialysis technique that retains 30 to 40 times more drugs of nanospheres being prepared.
INVESTIGATING THE EFFECTS OF MODIFIERS ON THE MECHANICAL PROPERTIES OF INJECTION MOLDED LIQUID SILICONE RUBBERS
The effects on mechanical properties of blending different levels by weight of talc, silica, and glass fibers in Liquid Silicone Rubber systems was investigated. Specifically, tensile strength, hardness, elongation, and compression set behavior was measured for unblended resin and each level of additive. A material property characterization was developed from these measurements. It was determined that talc and silica had better dispersion and both modifying and reinforcing effects, while the glass had none
INVESTIGATING THE SURFACE ENERGY OF SILICONE
Liberty Orchards is a company that makes some very sticky candies that make processing difficult. The current process requires refrigerating the candy slabs overnight and cutting the next day. By making a mold for casting the candy, the two processes would be eliminated, reducing the cycle time and the cost per part. Previous research has shown that silicone is a possible material choice. The project looked at various elastomers and fluoroadditives to reduce the surface energy of silicone. The different formulations have been tested based on the contact angle goniometer, tensiometer, water resistance, and SEM.
FAILURE ANALYSIS OF PLASTIC CRIMP FITTING ASSEMBLIES
This paper covers a failure analysis of a cross-linked polyethylene (PEX) hot and cold water plumbing system that utilized plastic insert fittings that were fastened with stainless steel clamp rings. The failed fittings exhibited features that led several different investigators to associate the failures with fatigue and slow crack growth. Our examination of the fractures indicated that the failures were due to high stress that caused crazing and subsequent fast fracture of the fittings. Environmental Stress Cracking (ESC) may also have been involved as a contributor to the failures.
EFFECT OF PROCESSING CONDITIONS AND DIE DESIGN ON DIE DROOL PHENOMENON FOR HDPE POLYMER MELT
In this work, the effect of processing conditions and die design on die drool phenomenon for HDPE polymer melt has been investigated. It has been revealed that the thermally induced degradation occurring inside the processing equipment may lead to HDPE melt viscosity/elasticity enhancement, which promotes unwanted material accumulation at the end of the extrusion die. It has been found that for particular processing conditions, shaped die, flared die or the use of hard chrome instead of stainless steel can reduce die drool phenomenon for HDPE.
HYPER-ELASTIC STRESS ANALYSIS OF LIQUID SILICONE RUBBERS
The purpose of this project is to develop hyper-elastic data for various liquid silicone rubbers (LSR). This will include designing a mold and test fixtures for molding and testing various LSRƒ??s. The goal is to collect data for Computer Aided Engineering (CAE) tools. There is generally no published data on tensile, compression, dynamic shear or biaxial strength to be used in CAE software at this time. After verifying the collected data with Finite Element Analysis (FEA) software, the results are as followed.
THE THREE DIMENSIONAL NUMERICAL ANALYSIS OF INJECTION-COMPRESSION MOLDING PROCESS
In this paper, the injection-compression molding process for thermoplastic materials is analyzed using a three dimensional simulation program. Injection-compression process is often used to produce parts with relatively small warpage at a low clamp force. An example case will be used to test the program. The program can be used to compare regular injection molded parts and injection-compression molded parts in terms of injection pressure, clamp force and dimensional stability.
AN INNOVATIVE ROTARY TOOL TECHNOLOGY FOR RAPID HEAT CYCLE MOLDING
A rotary tool technology was developed in order to reduce the cycle time of the RHCM process. The equipment consists of a hot molding cavity, a rotary plate with two cores conditioned at the standard processing temperature and a cold dummy cavity. The polymer is injected between the hot cavity and the core in the first station. Then the mold is opened and the part is trasfered to the second station. The mold is closed and the part is packed and cooled by the cold cavity. To test the proposed technology, a rotary mold for a TV frame was realized.
NUMERICAL ANALYSIS OF DENSITY GRADED FOAMS: TENSILE PROPERTIES
The tensile behavior of functionally graded (FG) foam plates were studied in this work. In order to analyze the mechanical properties of the samples, a finite-element method was used. The plate was divided into an arbitrary number of homogenous plates with perfect bonding throughout thickness. Then, the numerical analysis was used to describe the tensile properties of FG foams. The results show very good agreement with experimental data.
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