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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MELT FRACTURE BEHAVIOR OF PLA FOAMED USING DIFFERENT DIE ENTRY ANGLES
This investigation focuses on effects of die entry angles on the melt fracture behavior of foamed Polylactic Acid (PLA). PLA is foamed using a physical blowing agent along with four dies with varying entry angles. The dies used in this study have entry angles of 60, 90, 120, and 180 degrees. A camera is placed at the die exit to capture snapshots of the extrudate to examine the nature of melt fracture.
PASSIVE MULTI-SCALE ALIGNMENT AND ASSEMBLY
A significant barrier to widespread application of nano-engineered devices is the interfacing of small components. Current macro-manufacturing systems do not have the capability for the precise alignment nano-features require. In this paper, a novel method of self-alignment and assembly is discussed. This approach uses kinematic coupling and elastic averaging across multiple length scales to ensure alignment of the smaller features. Physical realization with ion beam etching, deposition, and thermal imprint lithography are also discussed.
FOAM INJECTION MOLDING OF GLASS FIBER REINFORCED POLYPROPYLENE COMPOSITES
This paper investigates the effects of the processing conditions on the foaming behavior of glass fiber reinforced polypropylene. Composites are injection molded by using an advanced structural foam molding machine with N2 as blowing agent. Samples are prepared with different processing parameters while mold pressure, void fraction and foam morphology are characterized. The results suggest that there is an optimal combination of these processing parameters, which can provide uniform void fraction and high cell density.
THE EFFECT OF CO2 ON THE MELT FRACTURE BEHAVIOR OF FOAMED PLA
The melt fracture behavior of foamed Polylactic acid (PLA) with the presence of blowing agent is studied in this investigation. A CCD camera is utilized to examine how foaming processing parameters such as blowing agent content, mass flow rate and temperature can affect melt fracture behavior. Images captured are used to analyze severity and nature of extrudate distortion.
FEASIBILITY OF DOUBLE CRYSTAL MELTING PEAK GENERATION IN PLA FOR EXPANDED PLA BEAD FOAMS
As the EPP and EPE bead foams have two crystal melting peaks, in order to manufacture expanded PLA bead foam (EPLA) with the same strategy, the feasibility of double crystal melting peak creation for PLA has been investigated in this work. The influence of various annealing temperatures and time on the double crystal melting peak creation is investigated for a linear and a branched PLA with two various degrees of crystallinity in a regular differential scanning calorimeter (DSC).
WIPER MOTOR DRIVE GEAR FAILURE ANALYSIS AND RESOLUTION
The global world of component sourcing offers many benefits to the supply chain, but can create obstacles to resolving quality problems and addressing failures. This paper describes a challenging failure analysis involving overseas manufacturing, extended usage prior to failure, an uncontrolled user environment, and only occasional failures. We discuss the investigation of the product, generation of the failure hypothesis, testing, recommendations and resolution of the issues.
IMPLEMENTATION OF A HIGHLY EFFICIENT MESHLESS METHOD FOR THE THERMAL ANALYSIS OF FOUNTAIN FLOW DURING FILLING IN INJECTION MOLDING
A computational model using a highly efficient local meshless technique to analyze the temperature development during a 2D slit filling is developed. Moving boundaries and the fountain flow effect are considered. The implementation is validated comparing the results with a finite element solution for a fix domain. The fountain flow thermal effect is studied, comparing the solution considering and neglecting this effect.
MICRO INJECTION MOLDING OF POLYMERS FOR BIOMIMICKRY OF ORGAN TISSUE
Two types of polystyrene were injection molded into macroscale parts with microscale features. UV photolithography was utilized to create microchannels on the surface of silicon wafers. Higher mold temperatures facilitated filling of the microfeatures. In addition, an undercut microchannel feature promoted pillar elongation. HIPS exhibited greater heights at identical mold temperature conditions. Pillars with heights of 15 µm were molded with an aspect ratio of 9.3. Polymer surfaces could provide control of biological cell activity
ASSESSMENT OF A NOVEL CO-POLYESTER RESIN THAT EXHIBITS EARLY STRAIN HARDENING BEHAVIOR
A hydroquinone modified co-polyester resin has been shown to exhibit early strain hardening behavior relative to conventional PET analogues based on equibiaxial film stretching data. This behavior was hypothesized to offer advantages in specific blow molding processing aspects, especially preform molding. A study was completed to validate this hypothesis and to better quantify the advantages that could be ascribed to early strain hardening behavior. The results of this study are reported herein.
CREATING MOLECULAR REBAR FROM MULTI-WALL CARBON NANOTUBES
Multi-wall carbon nanotubes have created much interest in theory but lack till now many applications that can create value. Designed Nanotubes has invented a process to produce high aspect ratio nanotubes in high yields called Molecular Rebar that can interact with materials and dramatically change mechanical, electrical, and heat properties of the materials demonstrating that the theory does work. Applications include tires (in development), batteries, composites and capacitors.
THE EFFECT OF TOOLING ALLOY ON THE PHYSICAL PROPERTIES OF AUTOMOTIVE POLYOLEFINS
It is common in the automotive industry to produce injection molds from P20 steel. However, several 7,0XX-series aluminum alloys have been identified by GM as P20 alternatives. The high thermal conductivity and excellent machining characteristics of these aluminums are enablers for cost reduction. Cost reduction is only good if there is no adverse effect on quality and performance. This paper will compare and contrast physical properties of samples molded using duplicate P20 and QC10 tooling.
TROUBLESHOOTING TPU EXTRUSION FOR RATE LIMITATIONS DUE TO SOLIDS IN THE EXTRUDATE
The extrusion of thermoplastic polyurethane (TPU) resins can be rate limited by the occurrence of solid polymer fragments in the extrudate. This paper will discuss the problem and identify a screw and process design that can mitigate the problem and allow high rates.
DEECOM®: A SUSTAINABLE PROCESS USED IN VARIOUS RECLAMATION PROCESSES
Polymer manufacturing utilizes metal parts which are reclaimed for reuse. Traditional reclamation methods utilize solvents and other chemicals which have high energy demand and involve expensive disposal methods. The DEECOM® technology, solvent-free relatively low temperature reclamation technology, is based on pressure swing techniques designed to physically disrupt and remove polymer from parts. The process mechanism results in filter reclamation procedures that have high degree of sustainability and provide opportunity to recycle the removed polymer.
DESIGN INNOVATIONS OF HIGH DENSITY POLYETHYLENE PIPE GRADE RESINS
The continued innovations in the molecular design of high density polyethylene resins have resulted in the development of PE 4710 bimodal resins. These high density bimodal resins have improved the physical attributes of polyethylene pipe such as increased durability, longer design life, increased pressure rating, and increased hydraulic capacity for plastic piping systems. In addition, the high performance achieved can be leveraged to various applications that require the same physical attributes.
RIGID POLYMERIC FOAM BOARDSTOCK TECHNICAL ASSESSMENT
Phenolic foam insulation is commercially available in Europe and Asia. Recently, a study was conducted that assessed the performance of European and Asian sourced phenolic foam versus North American extruded polystyrene (XPS), and polyisocyanurate (PIR) insulation products. This paper discusses the performance aspects of Phenolic foam insulation relative to both polyisocyanurate (PIR) and extruded polystyrene (XPS) foam. The findings are summarized and discussed herein: POLYMER ANALYSIS D33
SUBSTITUTING F-PVC WITH THERMOPLASTIC POLYOLEFIN ELASTOMERS
Flexible polyvinyl chloride has found suitability in a number of injection molded applications over the last several decades. While the material offers a very good balance of properties and processibility, it has come under scrutiny because of its plasticizer content and recyclability, especially in Europe. As such, there are many active programs to replace f-PVC. This paper will review design considerations beyond the datasheet to use when selecting a thermoplastic olefin elastomer to replace f-PVC.
NEW METHOD TO DETECT COLD FUSION JOINTS IN HIGH DENSITY POLYETHYLENE PIPE
This paper describes an innovative apparatus and method that uses electromagnetic energy in the microwave frequency range to volumetrically examine dielectric materials, including high density polyethylene piping fusion joints. This paper describes the theory of use and presents several HDPE inspection case studies. Specifically, this paper describes the mechanics of cold fusion joint detection and in several cases the inspection results are compared to mechanical test results that confirm the accuracy of the examination.
NEW DEVELOPEMNTS IN CO-ROTATING TWIN-SCREW EXTRUSION ELEMENTS FOR HIGH WEAR APPLICATIONS
Co-rotating twin screw extruders are the industry standard for processing filled resins. Rapid wear to high pressure sections in the extruder lowers product quality and increases downtime to change worn elements. More wear resistant element materials have been developed to lengthen the time between machine teardown requirements. A new HVOF method offers up to four times more wear resistance than standard options. This paper compares this new HVOF method of tungsten carbide protection with standard wear resistant options
BIO- ACRYLONITRILE BUTADIENE STYRENE (BIO-ABS): CREATING A NEW GREEN POLYMER THROUGH MELT BLENDING
In this paper, the method for design of a bio-based green material for use in electronics applications is discussed. The aim is substitution of currently used petroleum-based acrylonitrile butadiene styrene (ABS) with a bio-based polymer blend of poly(lactic acid) (PLA) and ABS. In this method, polymers will be melt blended and extruded to test their thermal and mechanical properties. The goal is to achieve performance of the blend equal or better to currently used ABS, as well as be a cost competitive alternative.
POLYBUTYLENE WATER SERVICE PIPE: THE OTHER SIDE OF THE STORY
Polybutylene pipe was once widely used in potable water distribution systems. However, problems occurred with the pipe's performance. It was claimed that the root cause of PB water pipe failures was in-service oxidative degradation of the material. These allegations ignored major problems with the installation of the PB water lines. This paper will show that installation issues far outweighed PB oxidation as the root cause of failure of PB water service lines.
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