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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BREAKTHROUGH INVENTIONS IN POLYMER EXTRUSION
Vast improvements in polymer extrusion processinghave been achieved through innovations in machinery,screw and barrel designs, functional operations,monitoring and controls, resins, and fundamentals.Selected examples are given to illustrate the breakthroughmachinery inventions that occurred in the past 50 years inthis field. These inventions and their technical andindustrial significance will be discussed. Selectedexamples include the conception of the single and twinscrewextruders, and the vast functional improvements thataffected market demand of extruded products withconsistent quality at ever higher production rates. Storiesbehind some of the breakthrough inventions will also bepresented.
CYCLIC BLOCK COPOLYMER EXTRUSION CHARACTERIZATION
Extrusion experiments were performed on three Cyclic Block Copolymer (CBC) resins using a highly instrumented single-screw extruder. These materials are substantially fully hydrogenated styrenic block copolymer and they represent a class of optical polymers with excellent light transmittance and unique birefringence properties. The data collected indicate that a screw designed with a compression ratio near 3.0 and a compression rate of no more than 0.0045 mm/mm should work well for the targeted application. These experiments also revealed that CBC extrusion behavior is more sensitive to block copolymer composition than molecular weight across the ranges studied.
PLUG MATERIALS FOR THERMOFORMING: THE EFFECTS OF NON-PLUG MATERIALS FOR THERMOFORMING: THE EFFECTS OF NONISOTHERMAL
The plug-assisted thermoforming process is the largest and most important industrial thermoforming process. The main aim of this study was to investigate the interaction between the properties of the plug and the polymer sheet in thermoforming. Non-isothermal plug only thermoforming tests were carried out using identical plug designs for various combinations of plug and sheet materials. It was hoped that this study would help to improve the understanding of friction and heat transfer effects during the thermoforming process. The plug materials used included: Hytac-B1X (thermoplastic syntactic foam), Hytac-WFT (epoxy syntactic foam with added Teflon), Blue Nylon, and POM (polyoxymethylene). The sheet materials included aPET and polystyrene (HIPS). It was found that the magnitude of slip during plug contact was much higher with aPET than with HIPS and that this reduced as the temperature of the plug was increased. Different plug materials produced significantly different wall thickness distributions in the preforms. It was concluded that friction was the dominant effect during contact.
THIN-WALL INJECTION MOLDING OF OPTICAL GRADE POLYMERS
Thin-wall injection molding experiments and mold filling analysis were performed on four Cyclic Block Copolymer (CBC) resins. These materials are substantially fully hydrogenated styrenic block copolymer and they represent a class of optical polymers with excellent light transmittance and unique birefringence properties. These resins are currently under development for various optical applications including injection molded light guide panels and lenses. The thinwall injection molding behavior and impact performance of the four CBC resins was compared to a competitive polymethylmethacrylate (PMMA) resin.
EPOXY POLYMERS TOUGHENED BY TRIBLOCK COPOLYMERS
A poly(styrene ' butadiene ' methyl methacrylate) triblock copolymer (SBM) and a poly(methyl methacrylate ' butylacrylate ' methyl methacrylate) triblock copolymer were investigated as a toughening agents for a ductile epoxy resin. A carboxyl acid terminated copolymer of butadiene-acrylonitrile (CTBN) was used as a control (conventional toughening agent).The use of CTBN resulted in micron-size rubber particles (c.a. 3 microns diameter) and the use of SBM and MAM resulted in spherical, nanometer size rubber particles (c.a 40 nanometers in diameter). Interestingly, the SBM modifiers were found to be more effective toughening agents at high rubber contents. Scanning electron microscopy attributes the increase in toughness due to extensive matrix dilation and transmission optical microscopy suggests that more energy is dissipated per unit volume for the SBM modified epoxy.
THERMAL AND RHEOLOGICAL PROPERTIES OF PHB SYNTHESIZED WITH VARIOUS HYDROXYVALERATE CONTENT FOR POTENTIAL USE IN FOOD PACKAGING
PHB (Poly (3-hydroxybutyrate) families of naturally occurring polymers are extracted from micro-organisms.PHB behaves similarly to conventional thermoplastics, yet are fully biodegradable in common composting conditions.To improve flexibility for potential food packaging applications, PHB can be synthesized with various copolymers such as 3-hydroxyvalerate (HV). The objective of this study was to characterize the thermal and rheological properties of PHB synthesized with various valerate contents and relate these findings to potential food packaging applications.
STYRENIC BLOCK COPOLYMERS FOR THERMOPLASTIC POLYURETHANE MODIFICATION
Urethane based thermoplastic elastomers (TPU) have an impressive range of performance characteristics such as outstanding scratch/abrasion resistance, excellent oil resistance and high tensile and tear strengths. However, application of TPUs is limited when low hardness (<70 A) is required. Soft TPU materials with low level of hard segment are difficult to process. Commercially, low hardness products are produced by adding phthalate plasticizers, which are not desirable in some applications. The objective of this project is to study TPU hardness modification using styrenic block copolymers to achieve soft TPU alloys without significantly sacrificing other physical properties.
REAL-TIME MONITORING OF INJECTION MOULDING FOR PART MASS DETERMINATION
A methodology is presented for determining moulded part mass from a combination of continuous process measurement and known polymer material pressure-specific volume-temperature (pvT) characteristics. The methodology determines the mass of melt that has been delivered to the mould cavity through the swept volume of the injection screw, but taking into account melt compressibility. The screw position is continually monitored by a computerized system along with the melt pressure and temperature. Results show a good correlation between the predicted and measured specimen mass over a range of processing conditions.
AN OVERVIEW OF ENVIRONMENTAL ALTERNATIVES AS VIEWED BY A PLASTICS INDUSTRY ECONOMIST
The plastics industry has been under heavy criticism from environmentalists for contributing to pollution and litter, exposing consumers to toxic matter, and using more than its fair share of energy resources. Are any of these accusations valid? If so, has our industry been responsive to these challenges in a meaningful way? Do the solutions offered by the environmentalists, to the problems they raise, have merit? This paper will attempt to address major environmental issues at they concern the plastics industry from an economic and scientific viewpoint and summarize what makes sense and what does not.
CURRENT APPLICATIONS OF TITANATES AND ZIRCONATES - 2010
Titanate and zirconate coupling agents as invented by the author generate approximately six ACS CAS abstracted works (technical papers, articles and patents) per week. The author will review the literature and update ANTEC attendees on applications in thermoplastics and thermosets with an emphasis on the latest work in nano and green technologies such as biopolymers and landfill biodegradation. For example, investigators Lei, Yong; Wu, Qinglin; Yao, Fei; Xu, Yanjun from the School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, LA, 70803, USA reported: Composites based on recycled high-polyethylene (RHDPE) and natural fibers i.e. pine wood flour and bagasse were made through melt blending and compression molding. The effects of the fibers and coupling agent type/concn. on the composite properties were studied. The use of maleated polyethylene (MAPE) carboxylated polyethylene (CAPE) and titanium-derived mixt. (TDM)-(20% pellet masterbatch of a neoalkoxy pyrophosphato titanate) improved the compatibility between the bagasse fiber and RHDPE and mech. properties of the resultant composites compared well with those of virgin HDPE composites. The modulus and impact strength of the composites had maxima with MAPE content increase. The composites had lower crystn. peak temps. and wider cryst. temp. range than neat RHDPE and their thermal stability was lower than RHDPE.""
FABRICATION AND CHARACTERIZATION OF POLYMER-BASED SILICA AEROGEL FOR ENHANCED MECHANICAL STABILITY
Silica aerogels have attracted attention for many applications due to their unique properties such as low density (0.003g/cm), mesoporosity (pore size 2-50nm), high thermal insulation and high surface area (500-1200m2/g). However, their fragility and environmental sensitivity restricts the use of monolithic silica aerogel. In this paper, silica aerogel that is cross-linked with diisocyanate is introduced and the effects of polymer concentration on aerogel properties, especially mechanical strength are discussed. Fracture of silicaaerogel mainly occurs at the interface of secondary particles that are formed during aging. It is believed that if the surface of silica aerogel is covalently bonded to nanocast polymer coating, the interparticle necks become wider and can reinforce the structure of the aerogel.
BREAKTHROUGH INVENTIONS IN POLYMER ANALYSIS FOR INDUSTRIAL APPLICATIONS - AN OVERVIEW
Explosive advances took place in all fronts of Polymer Analysis in the past 40 years. Selected breakthrough inventions in two of the most exciting areas, viz., thermal analysis and rheological analysis will be highlighted with emphasis on industrial applications. We'll discuss the evolutions, advancement, and impact to the industry and impact to science and technology as well as available stories behind these inventions. The selections were chosen from patent and journal articles on innovations such as DTA, DSC, TGA, thermal fractionations, TGA-GC, MASS, -IR etc., and MI, Mooney Viscosity tests as well as modern rheometers, polymer fingerprinting techniques.
Enhanced Water Stability of Soy Protein Plastics Using Acid Anhydrides
Protein based plastics were processed using anhydride chemistries in conjunction with glycerol to obtain modified soy protein polymers that were water stable. Formulations processed with chemistries such as maleic anhydride (MA) and phthalic anhydride (PTA) produced relatively water stable soy protein based plastics. Various formulations were produced by varying the anhydride content (3-10% w/w) in the final plastic mass. The respective mixtures were extruded and injection molded to form the samples for characterization. Formulations with 10% PTA were observed to have water absorption of only 19% after 24 hrs of water submersion as compared to 250% for the control formulation.
Temperature Effects on Slow Crack Growth in Pipe Grade PE
Temperature strongly affects the mechanical properties of pipe grade polyethylene (PGPE), such as strength and toughness. It is observed in this study that the temperature also affects the mechanisms of slow crack growth (SCG). A change in the mechanism of SCG is observed at certain temperature, named Crack Growth Transition Temperature (CGTT). The CGTT of the cold drawn (oriented) PGPE appears to be significantly higher than room temperature. At the temperature above CGTT the crack propagates discontinuously, stepwise, whereas at the temperature below CGTT the crack grows continuously. The slope of crack growth rate vs. stress intensity factor (SIF) is also noticeably different for temperatures above and below CGTT. The existence of CGTT implies certain limitations for commonly used extrapolation of SCG and lifetime data from the elevate temperature of an accelerated testing to the room temperature across CGTT.
DISPERSION MORPHOLOGY OF ORGANOCLAY IN ACRYLONITRILE-BUTADIENE-STYRENE/POLYAMIDE 6 /ORGANOCLAY TERNARY NANOCOMPOSITES
In this article, polyamide 6(PA6)/Organoclay masterbatch were prepared by melt mixing, and then acrylonitrile-butadiene-styrene(ABS)/polyamide 6(PA6)(70/30,w/w) nanocomposites were prepared by the melt mixing of PA6, ABS and organoclay. The effect of organoclay platelets on dispersion of ABS/PA6/organoclay ternary nanocomposites had been investigated by wide angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM). Morphology analysis revealed that organoclay platelets were selectively dispersed and exfoliated in PA6 phase, but some were located in interface of PA6 and ABS phase.
AN EVALUATION OF THE PERFORMANCE OF DRIVE SYSTEM CONFIGURATIONS IN SINGLE SCREW EXTRUDERS
A comprehensive study was conducted using three different types of extruder drive and motor configurations for a single screw extruder under identical conditions to compare the energy efficiency. Sound emission data was also measured and compared. Two systems of a conventional design used an AC or DC motor in combination with a mechanical gear reducer and were compared to a Direct Drive system using only a torque motor. The study showed that the Direct Drive system operated at higher energy efficiency and produced lower sound emissions compared to the AC & DC conventional systems. The results show that at the base speed of the drive train, the DC system consumed 10% more energy (kW) than the AC system, and the Direct Drive system consumed between 12 and 15% less energy than the AC system, depending upon the torque required.
INVESTIGATIONS ON THE INTERACTION OF THERMOPLASTIC SURFACES AND PLASMA PROCESSES
Plasma processes constantly gain importance in the field of plastics processing. They are influenced by production parameters on one hand and the substrate itself on the other hand. The properties of polymers vary substantially depending on their processing conditions or their history. This paper describes investigations on the plasma modification of polyamide (PA6) and polypropylene (PP). This includes the examination of the influence of absorbed water in the surface near regions of the bulk material as well as the interaction with the polymeric microstructure. The knowledge of this interaction between plasma and thermoplastic surface can be used for the process development or quality assurance in terms of plasma-assisted modification of polymers.
Renewable Resource-Based Composites for the Automotive Industry
The incorporation of renewable resources in composite materials is a viable means to reduce environmental impact and support sustainability efforts in the composites industry. This paper will focus on unsaturatedpolyester resins prepared from renewable resources and their use in composite materials. Applications of these resins in the automotive industry will be described including a comparison of properties and performance vs. typical petroleum-based resins.
Development of Injection Moldable Composites Utilizing Annually Renewable Natural Fibers
In order to advance the commercialization of natural fiber reinforced plastics for automotive use a partnership was formed between academia natural fiber processor material supplier and OEM. This partnership improved the communication along the supply chain and resulted in optimized material properties to meet OEM specifications and application part performance. Several products have been developed that meet current material specifications offer significant weight savings over conventional mineral- and glass-reinforced composites and are competitively priced.
Economical Preform Production for Conventional & Natural Fiber Composites
This paper presents an independent cost analysis for a novel slurrybased preform technology in order to understand its potential benefits across a range of component and reinforcement scenarios. Specifically the economics for small medium and large automotive composites reinforced with glass carbon and natural fibers through the use of manual sprayup automated P-4 and slurry preforming are examined and compared through technical cost analysis. The molding economics of SMC RTM and SRIM are also addressed in detail.
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