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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THE FIVE FACTORS THAT CONTROL TOOL ROOM PERFORMANCE
Molding shops and mold builders realize more and more that the continued practice of a re- active “fixes it when it breaks” maintenance strategy is an exercise in futility. Excessive tooling and labor costs, missed production shipments and repeating part quality issues caused by knee jerk solutions and quick, cheap repairs stifle company growth. Changing a long standing re-active maintenance culture involves understanding the “5 factors of focus” that control tool room performance.
THERMOFORMABLE LIQUID CRYSTAL POLYMER (LCP)
Thermoforming is an economical process for forming large shape products. High performance liquid crystal polymer (LCP) has high thermal stability, excellent dimensional stability and high chemical resistance, which offers new application opportunities in demanding applications. In this paper, a new thermoformable LCP resin is compared with injection molding LCP on mechanical, thermal and rheological properties. Sheet extrusion and thermoforming process conditions are discussed.
THE EFFECT OF COOLING RATES ON GAS PENETRATION AND FINGERING OF GAS-ASSISTED PLASTIC AND POWDER INJECTION MOLDING
The effects of cooling rate on gas penetration depth and residual wall thickness (RWT) of gas-assisted injection molding (GAIM) parts was investigated for polypropylene (PP) and for stainless steel powder feedstock (SSPF). Gas penetration depth and RWT of PP in SLA and in Al cavities did not show any significant difference. However, gas penetration and fingering of SSPF in SLA and in Al cavities were found to be different.
EVALUATION OF LONG-TERM PERFORMANCE OF GFRP FOR HOT WATER APPLICATION BY INJECTION MOLDING
In this study, the long GFR-PPS and short and long GFR-SPS were tested to evaluate the long-term performance at the elevated temperature in water and in air. As a result, tensile strength of there after 10000 hours at 150°C in hot water decreased to 60% or less due to degradation at the interface between matrix resin and GF.
PLUG ASSIST MATERIALS FOR IMPROVED TRANSPARENCY WHEN FORMING POLYPROPYLENE
To avoid scratching issues associated with syntactic foam, solid engineered polymers have been used as plug assist materials for forming transparent polypropylene. A new class of syntactic foam with a copolymer epoxy base has been designed to minimize scratching and improve clarity when forming transparent materials. The performance of copolymer syntactic foams for forming transparent polypropylene was evaluated and compared to the performance of engineered solid polymer and a traditional grade of thermoplastic syntactic foam.
COMPARATIVE STUDY OF WOOD-PLASTIC COMPOSITES BASED ON BIODEGRADABLE POLYMERS
This research was performed to compare mechanical properties of wood-plastic composites based on PLA and PLA/PBS blend. Wood-plastic composites were prepared by melt compounding 70 wt% plastics; PLA, PLA/PBS 70:30 wt% blend, or PP; and 30 wt% pine wood fibers. A suitable coupling agent was used to improve compatibility between polymer matrix and wood fibers. Tensile, flexural, impact and fracture toughness were evaluated and compared. Phase dispersion and interfacial adhesion was studied by SEM.
THE EFFECT OF POLYHYDROXYBUTYRATE-CO-VALERATE (PHBV) CONTENT ON THERMAL, RHEOLOGICAL, MECHANICAL PROPERTIES AND FOAMING BEHAVIOR OF POLYLACTIC ACID (PLA)
This paper examines the effect of PHBV content on the properties of PLA-PHBV blends and their foams. PLA and PHBV blends were manufactured in various compositions via compounding, and their tensile, thermal and rheological properties and their foam morphologies were characterized. The results indicated that although PLA and PHBV are immiscible, the addition of small quantities of PHBV (up to 30 wt%) lead to a finer and more homogenous cellular morphology.
MODIFICATION OF MECHANICAL PROPERTIES OF POLYBUTYLENE SUCCINATE USING IN-SITU COMPATIBILIZATION BLEND WITH POLY(LACTIC ACID)
PBS/PLA blends in various blend ratios added GMA to modify their compatibility were prepared using melt blending. Mechanical properties of polymer blends before and after in-situ compatibilization were investigated. Morphology and compatibility of modified blends was studied via SEM and DSC, respectively. PBS/PLA 50:50 wt% added 10 wt% GMA exhibited high percentage of elongation at break in a range of LDPE due to co-continuous structures. This phenomenon also benefited the impact strength of modified blends.
PORCERAX II, 101 HOW TO PROPERLY MANUFACTURE, USE AND MAINTAIN YOUR PORCERAX INSERTS.
Properly used and maintained Porcerax II, the self venting mold steel, will allow molders to reduce cycle times, injection pressure and scrap due to short shots, sink, and material burning. Design considerations should include: 1. Resins used 2. Surface finish of plastic part required 3. Size of problem area 4. Proper thickness of insert 5. Proper venting on cavity and backside of insert for optimal venting. 6. Molding vertical walls with Porcerax II 7. Ability to remove the insert for periodic cleaning
ADSORPTION AND BARRIER PROPERTIES OF PET/PP BLEND IN INJECTION MOLDING
This research was evaluated the adsorption and barrier properties of PET, PP. The results showed that MVTR of the blend samples decreased with increasing PP contents while the residual rate of L-menthol decreased when increasing PP contents in blend. Therefore, the adsorption amount of a model compound, L-menthol tended to increase with increasing PP contents in the blends. However, the barrier effectiveness of the blends has been improved by the contribution of the PP.
DISPERSION OF SINGLE-WALLED AND MULTI-WALLED CARBON NANOTUBES IN UNSATURATED POLYESTER RESIN
Several strategies were explored for dispersing carbon nanotubes were dispersed in unsaturated polyester resin (UPR). CoMoCAT single-walled carbon nanotubes (SWNTs) were more difficult to disperse than HiPco SWNTs. Oxidation of nanotubes decreased the dispersion quality. Dodecylation via the Billups reaction also failed to improve dispersion quality. Polystyrene grafted from carbon nanotubes was found to be a promising strategy for dispersing both single-walled and multi-walled carbon nanotubes in UPR.
ENVIRONMENTAL STRESS CRACKING OF POLYCARBONATES EXPOSED TO SUNSCREEN AND HAND LOTION
Three general purpose polycarbonate (PC) resins and one PC-siloxane copolymer were injection molded, then exposed to isopropyl alcohol (IPA), hand lotion, and SPF 30 sunscreen while under strain. The hand lotion exhibited the most aggressive environmental stress cracking (ESC) behavior. Effects of molecular weight, polymer composition and annealing are addressed. Scanning electron microscopy of an ESC fracture surface is also presented.
NITRILE RUBBER-BASED NANOCOMPOSITES PREPARED BY LATEX COMPOUNDING OF POSS MODIFIED CLAY
Nanocomposites of HNBR latex and modified clays were prepared by latex blending. The results of x-ray diffraction show that using a reswell technique with trisilanolphenyl POSS with MMT and rubber provides a large d-spacing as well as a mainly exfoliated structure. Modified clay in the latex affords no change in thermal degradation temperature. POSS modified clays successfully provide thermal stability and an intercalated or exfoliated structure when mixed with latex rubber.
DEVELOPMENT OF DRYLESS PELLET -APPLICATION OF PELLET ENGINEERING
This study was carried out to clarify a relationship between moisture absorption fraction and higher-order structure of dry-less recycled PET pellets. Karl Fischer moisture titration, differential scanning calorimetry (DSC), microscopic Raman spectroscopy and scanning electronic microscope (SEM) were used to characterize the pellets to determine distinct structures that differentiates the dry-less pellets with normal pellets.
THE EFFECT OF MACHINE DIRECTION ORIENTATION ON MULTILAYER HIGH BARRIER FILMS
The effect of machine direction orientation (MDO) on high barrier packaging films was investigated. Multilayer films incorporated an ethylene co-vinyl alcohol (EVOH) core and polyolefin skin layers. Total film thickness and layer configuration were varied to determine the effect on film performance and compatibility with the orientation process. Films underwent a 4:1 stretch ratio, and displayed a 33% reduction in oxygen permeability, a 75% increase in modulus, and a five time increase in tensile strength.
IMPROVED MANGEMENT OF PRODUCTION AND CAPACITY THROUGH APPLICATION OF MOLD BASED DATA COLLECTION
There are multiple methods of tracking and monitoring mold performance and production output using on-board machine data count or discrete network-based systems within a production facility. However, these techniques miss the complete history of the mold from first trials through its life in production and including maintenance intervals and component design changes. Using on-board mold monitoring allows transparency and control of capacity, modifications and maintenance of the mold to deliver better overall performance and cost.
NOTES ON THE MICROPELLETIZATION OF POLYMER RESINS
Manufacturing spherical polymer micropellets has been possible with a new technique that uses air to impose surface disturbances on an extrudate. Observations of experimental results considering properties of the melt are taken as the starting point for a deeper understanding of the behavior of polymer resins of interest in the production of micropellets. Such relationships include aspects of material properties as well as processing conditions.
THE AMERICA INVENTS ACT: SIX KEY CHANGES IN U.S. PATENT LAW
On September 16, 2011, the President of the United States signed into law the Leahy-Smith America Invents Act. This law includes some of the most significant changes to U.S. Patent Law since the early 1950’s, changing the U.S. patent system to a “first to file” system. The Act also introduces procedures, such as post grant review and supplemental examination, and alters existing procedures such as inter-partes re-examination.
EFFECT OF FIBER SURFACE TREATMENT ON THERMAL AND MECHANICAL PROPERTIES OF JUTE MAT REINFORCED POLYCABORNATE COMPOSITES
This paper presents the possibility of using natural fiber as reinforcement for engineering thermoplastics composite. Jute mats from waste coffee bag were treated by thermoset resin such as flexible epoxy resin (FE) to improve their thermal resistance prior to compression mold with polycarbonate (PC). The effects of epoxy contents on thermal properties and mechanical properties of the composites were investigated.
FLOW INSTABILITY IN MULTI-LAYER CABLE COATING DIES
The paper describes the study of a flow instability defect in a coextursion, cable coating process. The problem was first analyzed using a 2D Finite Element flow simulation. It was determine that the outer layer was experience very high deformation (velocity changes) when merging with the next inner layer. The problem was solved by modifying the coextruson die to reduce the velocity differences that the material experienced in the merge region. This modification stabilized the coextrusion process and removed the instabilities so that acceptable product could be made
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