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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Time Temperature Superposition of Short Term Stress Relaxation Behavior to Understand Retention of Material Modulus over Time
Several engineering thermoplastics, because of their higher mechanicals, thermal and dimensional stabilities, are increasingly being considered for use as injection molded components, in several industrial applications . There are several load bearing applications, such as springs, bearings, gears, valves etc., wherein during short term, it could be subjected to constant strain under varying temperature and humidity levels . It is of interest to have an understanding, if such materials during end-use, has the ability to retain modulus over a short period of time. Therefore, linear visco-elastic limit of the material needs to be determined under the influence of strain, temperature and moisture. To assess such performance attributes of materials, short-term tensile stress relaxation studies were conducted, using Universal Tensile Instrument, under varying strain levels, temperature and humidity in a 1-hour timescale. The study revealed that the material retained linear visco-elastic behavior in the range of 2% strain until 60°C and moisture was found to have no impact. The relaxation modulus measured from this experiment was also extended using a master curve using Time-Temperature-Superposition (TTS) up to 10 hours. Such an analytical technique could be used for material screening by product developers. Going forward, if there is need to assess the performance of the material over a longer period (>10 hours), the laboratory experimental duration can be proportionately increased.
The Flameretardancy Study of PVA Using for Furniture Made from Corrugated Cardboard
Corrugated cardboards have truss structure, so these have advantageous in terms of specific strength, workability, price and recycling efficiency. Because of these properties, corrugated cardboards are used as not only packing materials but also furniture etc. When a disaster caused in Japan, refugees sleep directory on the floor with a blanket. It caused the second healthy damage like the economy class syndrome. For prevent refugees from its damage, beds made from corrugated cardboard has been used instead of cots in Japanese shelters. We need to give flameretardancy to the cardboard bed for enhancing safety. In this research, flameretardancy of corrugated cardboards is aimed to using Poly-vinyl alcohol (PVA). PVA is useful for the coat of the cardboard. The coating PVA on the cardboard is possible to be recyclable, because PVA has water solubility. We used 2 kinds of flameretardant in this time. In the result of combustion test, the Halogen, Phosphorous and Nitrogen based compound show great flameretardancy for PVA.
Development of an Injection Molded Automotive Hoop Spoiler
This paper presents the development and application1 of a large injection molded sports hoop spoiler (IMSH) for a pickup truck that replaces an already existing industry norm blow molded sports hoop (BMSH).
The new injection molded design has provided the opportunity to include an internal structure that does not exist in the blow molded design, hence allowing for an increase in the static and dynamic performance as well as provide a lower cost, lighter weight, with less assembly components.
The new IMSH has incorporated design features to compensate for durability and thermal loads that are applied in normal usage, which allows the outer visual structure to move with respect to the inner support structure, without stressing either structure whilst producing a good external craftsmanship finish.
Production of In Situ Microfibrillar Composites as a Novel Approach towards Improved Bio-Based Polymeric Products
In this work, we introduce the in situ microfibrillation of poly (lactic acid) (PLA)/polyamide-6 (PA6) blends as an effective approach in improving PLA’s properties as well as its foaming-ability. The in situ microfibrillation of the PLA/PA6 blends was performed using a facile and cost-effective extrusion process followed by hot stretching of the extrudates. The morphological studies proved the successful formation of fully stretched PA6 microfibrils with diameters as low as 200 nm. Inclusion of a small concentration of PA6 microfibrils (3 wt.%) was shown to lead to significant improvements in the crystallization kinetics and mechanical properties of PLA. In addition, formation of a physically entangled network of PA6 microfibrils improved the melt strength and elasticity of PLA which, in turn, improved the microstructure of PLA foams.
Determination of CO2 Solubility and Volume Swelling in PMMA in Light of Retrograde Vitirification
The solubility of CO? in Poly (methyl methacrylate) (PMMA) and the pressure-volume-temperature (PVT) behavior of PMMA-CO2 mixture were investigated in light of the retrograde vitrification process using a magnetic suspension balance (MSB) and an in-house visualization dilatometer; experiments were carried out 20 to 100 °C at 54 atm. The results indicate that as the temperature decreases the swelling increases, although, when a decrease in temperature caused the phase of PMMA to change from liquid to glassy, the swelling decreased. However the solubility increased throughout the drop in temperature. The increase in the solubility with respect to temperature was not a linear trend, illustrating the effect of phase of PMMA on the solubility of CO?.
Measuring Thermal Crystallinity in PET
The mechanical properties of poly (ethylene terephthalate) (PET) depend on the degree of crystallinity. PET crystallizes from both thermal and strain-induced process paths. Strain-induced crystallization occurs under uniaxial or biaxial stretching, the latter is common in stretch blow molding. Thermal crystallization takes place when cooling from the melt or under sustained elevated temperature which are both common during injection and blow molding. The current work focuses on comparing methods used to quantify the percent thermal crystallinity in injection molded water bottle preforms. An injection molded preform with a gradient of induced thermal crystallinity was examined using Differential Scanning Calorimetry (DSC), Micro X-ray Diffraction (?XRD), and Raman Spectroscopy. Correlating these three techniques for percent thermal crystallinity, helps with the development of nondestructive crystallinity measurement methods to aid with process optimization and part quality.
Mechanical Property and Fractrue Analysis of Wood Powder/PP Composite Molded by Injection Molding
The use of wood plastic composites (WPCs) has been increased in various applications owning to low prices, low density, ecological and economical advantage, less hazards. Due to the wood powder could be produced from offcut materials which can raise the utilization ratio of timber. The objective of this research is to use composite combining with plastic and wood to relieve the depending on timber. At current study, two kinds of materials were developed with wood powder and were compared with polypropylene. Mechanical property including tension and Izod impact were evaluated. The fracture behavior of wood powder composite was observed to analyze the relation between mechanical property and combination between wood and polypropylene.
Scratch Behavior of Polyurethane Elastomers with Variation in Soft Segment Type
An investigation on the effect of soft segment type on the scratch performance of cast polyurethane elastomers (CPU) is reported. A series of CPU were synthesized by the same isocyanate and chain extender, 4,4'-methylene diphenyl diisocyanate (MDI) and 1,4-butane diol (BDO), to form the same type of hard segment, with four different soft segments (polyols): polytetramethylene ether glycol (PT), polycaprolactone (PC), ethylene oxide and propylene oxide based polyether polyol (PET) and adipic anhydride based polyester polyol (PES). Scratch tests were carried out according to the ASTM D7027-13 standard. CPU-PET system is observed to exhibit the worst scratch resistance while CPU-PT shows the best. Coefficient of friction measurement, quasi-static uniaxial compression tests as well as dynamic mechanical analysis (DMA) were investigated to correlate with the observed differences in the scratch performance of the CPU model systems.
High Performance High Density Polyethylene (HDPE) for Hot Fill Closure Applications
High performance bimodal high density polyethylene (HDPE) was developed for the hot fill closure applications. Performance of the bimodal HDPE was benchmarked versus incumbent unimodal HDPE resins. The bimodal HDPE resin delivered better environmental stress cracking resistance (ESCR) than a conventional HDPE homopolymer while maintaining a good heat deflection temperature (HDT) and a good Vicat softening point. The high performance HDPE also exhibited greater shear thinning behavior, indicative of good processability under the high shear rates typically encountered in the injection molding process. In addition, the closures made from the new HDPE resin are advantaged with respect to the removal torque.
Comparative Testing of Pre-Pigmented and Natural Compound plus Black Coloring Master Batch HDPE Pipes for Potable Water Applications
A study was initiated to demonstrate that the use of HDPE natural compound plus coloring master batch can be used to meet the requirements of ISO 4427:2007 potable water pipe standard. A test matrix was developed to evaluate a pre-pigmented black HDPE compound and two versions of blended natural compound plus black coloring master batch for conformance to the requirements in three different parts of ISO 4427:2007. One blend version used a typical North American black coloring master batch with a nominal carbon black particle diameter of 58 nm. The other blend version evaluated a black coloring master batch that met the ISO 4427:2007 carbon black average particle diameter requirement (10 – 25 nm). 110 mm PN16 pipe (standard dimension ratio of 11) was produced from all three materials using the same extrusion equipment, temperature profile and extrusion rate. The results of the conformance testing are discussed as well as recommended steps for the use of natural compound and coloring master batch in regions of the world with experience in pre-pigmented HDPE pipe compounds.
Enhancement of Paint Adhesion with Polyolefin Blends
Adhesion of coatings to molded polyolefin articles is a well-known challenge due to the low surface energy of polyolefin materials. This study examines the influence of substrate composition and morphology on adhesion. It has been observed that the composition of the substrate plays a role in the adhesion performance of paint systems due to changes in the surface morphology and chemistry. By engineering the surface morphology of the molded polyolefin, adhesion of paint can be significantly improved and may ultimately lead to a path for low cost, facile decoration of materials in markets where they are currently not in use today.
Influence of Elastomer on Morphology and Mechanical Properties of Nylon 6/OMNT/Elastomer Composite
Nylon 6/OMMT/elastomer composite was first prepared by molten compound method and then how its rheological properties, mechanical properties, micro morphology and the shape of fracture surface vary with elastomer content was investigated. The results indicate: With the increase of elastomer content, impact strength increases significantly, tensile strength, flexural strength and modulus decline and elongation at break declines first but then increases?the SEM images of fracture surface go well along with the results of impact tests, and critical matrix thickness for the composite materials of brittle ductile transition layer is 0.14?m. With the increase of elastomer content, the apparent viscosity increases first but then declines, non-Newtonian index declines and the activation energy declines first but then increases. So adding elastomer makes it possible for Nylon 6/OMMT/elastomer composite to flow steadily in a wide temperature range under a constant shear stresses and makes the composite easy to fabricate.
Microscopy of Intentionally Oxidized Polypropylene-Based Mesh Material
Surgical mesh and sutures made from polymer materials have long been utilized as medical devices. Several polymeric materials have been employed to manufacture these devices, including polypropylene. PROLENE® fibers, comprised of polypropylene-based material with added antioxidants, pigment, and processing aids are fiber spun and used in medical sutures and pelvic mesh implants. Claims of in vivo degradation of mesh devices, including PROLENE®, have been investigated by others [1-7]. Surgical mesh is typically surrounded by tissue during and after implantation. Histological dyes such as Hematoxylin and Eosin (H&E) can be used to stain surrounding tissue on explanted devices. Using optical microscopy, we demonstrate that non-implanted, intentionally oxidized, PROLENE® fibers do not stain with H&E. The inability of PROLENE® to become stained is an important finding as it provides histologists and others a means of delineating between biological material surrounding mesh and the fibers that are used to construct the mesh.
Modern Fabrication of Poly(Lactic Acid) Nanofibers by Cotton Candy Method
Poly(lactic acid) (PLA) nanofiber was prepared using cotton candy method. The nozzle temperatures were varied from 210-260 °C. PLA was fed to extruder then melted PLA was accelerated through small nozzles by hot air pressure. The effect of nozzle temperatures and air pressures on morphology, an average diameter and thermal properties of PLA nanofiber was determined. SEM results suggested that PLA fibers were straight and smooth at low nozzle temperatures. The diameter of fibers decreased with increasing the nozzle temperatures with regardless on the air pressures. MFR and thermal properties informed that PLA degraded at the nozzle temperature higher than 230 °C. The optimized condition was fallen at the nozzle temperature of 250 C with air pressure of 0.2 MPa. The average diameter was around 500 nm at the productivity of 140g/h.
Bridging the Gap: Liquid Solutions for Joint Sealing
Adhesive sealants are used to seal a surface and prevent the passage of a liquid or gas. Henkel’s innovative industrial sealants are the result of consultations with industry experts and the company’s analysis of realworld production environments. Maintaining or improving efficiency is Henkel’s primary focus; making sure our industrial sealants work right the first time and every time. There is a multitude of sealing applications that arise in practice. The most common sealing applications suited for adhesives are gasketing and seam sealing. Henkel also provides solutions for more niche applications such as weld porosity sealing or casting porosity sealing.
Time Is Money: High Speed Adhesive Solutions for Instant Bonding
Over the last century, cutting down manufacturing costs and time using faster assembly methods has been a high priority for many companies. Bonding methods that are reliable, as well as easy to use and automate cut down on these added expenses associated with assembling and manufacturing products. Advancements in adhesive technologies, included improved performance cyanoacrylates, the development of hybrid structural instant adhesives, low pressure molding adhesives as well as polyurethane reactive hot melts have allowed instant bonding to outperform mechanical and thermal joining methods by providing reliable, repeatable bonds for virtually all substrates on a fully automated production line.
Fabrication, Morphological Evaluation, and Characterization of Semiconducting Oxide Nanofibers from Gas Jet Fiber Spinning Process
In this paper, we report that Gas Jet Fiber (GJF) spinning is an efficient process to fabricate sub-micrometer and nanometer sized single or bi-component semiconducting metal oxides (SMO) fibers with different morphological forms like mesoporous or solid cylindrical, core-shell (CS) and side-by-side (SBS). SMO fibers with tailored morphology are fabricated via GJF spinning from polymer template in conjugation with conventional precursor solgel chemistry. The GJF-spun fibers are systematically characterized using SEM, TEM, EDX, N2-BET surface analyzer, and XRD for their morphological and crystallographic studies.
Characterization of Polypropylene/Bamboo Fiber Composites Modified with Polyethylene Grafted Maleic Anhydride
Bamboo fiber (BF) was compounded with polypropylene (PP) in twin screw extruder at bamboo fiber contents of 0-30 wt% with linear low density polyethylene grafted maleic anhydride (LLDPE-g-MA) as modified agent. PP/BF composites were fabricated to dumbbell specimens by injection molding. The effect of bamboo fiber contents on mechanical properties, fracture toughness, morphology and thermal properties of PP/BF composites was investigated. Tensile and storage modulus of the composites increased when increasing bamboo fiber contents. It can be noted that bamboo fiber promoted crystallization and enhanced crystallinity of PP in the composites, which improved the composites mechanical performance. On the contrary, tensile strength of the PP/BF composites was almost unchanged. It can be noted that fracture toughness of the PP/BF composites was maintained at the BF contents of 10 wt%, which was attributed to the good interaction between bamboo fiber and PP matrix with the addition of LLDPE-g-MA.
Effect of Anhydride Type on Structure and Thermal Properties of Poly(Propylene Carbonate) Composites Produced by Reactive Extrusion
Poly(propylene carbonate) (PPC) is an environmental friendly thermoplastic aliphatic polycarbonate. To broaden the application of this material, three types of anhydride (maleic anhydride (MA), phthalic anhydride (PA) and pyromellitic dianhydride (PMDA)) were melt blending to end-cap PPC by reactive extrusion. FTIR, Raman spectroscopy, TGA, and intrinsic viscosity test were used to characterize structure and properties of anhydride end-capped PPC. Results indicate that the reaction mechanism between PPC with MA was different from PPC with PA and PMDA. Intrinsic viscosity test demonstrates that molecular weight of PPC-PMDA was higher than that of pure PPC. In addition, TGA results show that the thermal degradation temperature of PPC could be improved by adding three types of anhydride, and the T-5% of PPC-PMDA was the highest and increased by 26.3 ºC.
The Surface Resistance Value and Physical Properties of Conductivity Fiber Filler-Compounded PES
Although the high-strength resin has been developed as a metal substitute, many resins are mostly to be an insulator that does not conduct electricity. There is a tendency for hoarding the static electricity. Therefore, highly conductive metal is used as jig and parts that related to precision parts of vehicle mounted.
PES (polyether sulfone) is an amorphous plastic, which is high heat resistance. In order to impart conductivity, the conductive filler and PES were compounded and measured the surface resistivity and physical properties.
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