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.
The paper discusses how flow simulation is used to analyze and optimize the design of the coextrusion feedblocks. The results help to explain the reason behind certain design arrangements. A case study of a problem encountered in an actual, three-layer film production will be used to demonstrate how the design of the feed block merge section and the material flow properties, especially the elongational viscosity, can create conditions for the “wave” type interfacial instability.
A comparative rheological study of four pairs of isotactic and syndiotactic polypropylene resins with similar MFI was conducted. The rheological tests included double bore capillary rheometry, frequency sweeps and creep and recovery compliance. It was found that, for similar MFI, the viscoelastic behavior is significantly different between these two types of resins which suggest that stereoregularity has an important effect on the viscoelastic behavior of polypropylene melts.
Mixed tocopherols, ?-tocopherol, and ?-tocopherol were evaluated for antioxidant performance in ABS using oxidation induction time as the response. Three commonly used phenolic antioxidants and vitamin E (?-tocopherol) were used as controls. Mixed tocopherols were found to have a greater antioxidant effect than the hindered phenolic AOs or vitamin E in ABS. ?-tocopherol was found to be primarily responsible for the improved performance of mixed tocopherols.
During the injection molding process, shearinduced imbalances can have a drastic affect on many material properties. Samples of tensile bars were molded using an amorphous and semi-crystalline material at three different injection rates. The tensile bars were then Izod impact tested based on the location of the hot and cold side of the bars. A comparison was made to display the effects of the imbalances. The resulting impact strengths were then graphed accordingly and compared within each subgroup.
Nanocomposites based on biodegradable polycaprolactone (PCL) and mica clay organically modified with L-arginine were prepared through solvent blending. Their properties were analyzed with TGA, DSC, and tensile testing. The addition of the organically modified clay caused an increase in properties, but at large incorporation, properties began to decrease. Samples of 3%, 5% and 10% organically modified clay were compared to pure PCL.
Interest in transportable modular production plants is on the rise. These containerized solutions combine flexibility with minimal expense for installation and start up. This presentation will highlight the issues surrounding a successful implementation of this concept for an insulated pipe construction used for offshore crude oil transport.
Injection molding barrel temperatures have high interaction and slow responses. The classical proportionalintegral-derivative (PID) control has difficulties to control for them accurately. An adaptive multi-input-multi-output (MIMO) generalized predictive control (GPC) scheme is developed, implemented and tested for barrel temperatures control of a reciprocating-screw injection molding machine. Experimental results illustrate GPC superiority over the traditional PID control.
This work examines the foam density of polystyrene (PS) blended with low density polyethylene (LDPE) at various ratios and the thermal conductivity of vacuum insulation panels (VIPs) using PS/PE with filers foams as core materials. The experimental results indicate LDPE strongly influences the foam density of PS/PE foam and the content of open-cell in PS/PE with fillers foam. A higher content of open-cells in PS/PE with fillers foam can lead to a lower thermal conductivity of VIP.
Composites consisting of the same material with different reinforcement and matrix shapes, such as fibre and matrix phases, can create high interfacial strength. This paper concentrates on the experimental investigation of all-polypropylene single phase composites. It is interestingly noteworthy that reinforced homo PP composites exhibited superior energy absorption capability when compared with their virgin counterpart for both static and dynamic impact test.
We have carried out experiments on UHMWPE in uniaxial compression in which we have measured the stress-strain and stress relaxation behaviour, covering a wide range of strains and strain rates. A constitutive model that makes use of Eyring processes has been developed and implemented numerically. This model can represent rate-dependent stress – strain behaviour. We have derived a set of values for the model parameters such that it gives a good representation of the observations.
This paper presents a true three-dimensional numerical simulation of the mold filling and packing in injection-molded part. The segregated finite element method and control volume finite element are combined with VOF method to solve the flow/temperature field and to track the melt front advancement during the process. The iterative solver (SOR) was employed for the solution of the equations. Several numerical examples are compared with Hele-Shaw approximation.
Radio Frequency (RF) welding, also known as High Frequency (HF) welding, is often a preferred means of fabricating products made of polar thermoplastic materials. Thermoplastic materials with low dielectric loss factors, such as thermoplastic vulcanizates (TPVs) have presented a challenge to RF welding. Modification of traditional RF welding equipment has been studied to characterize successful RF welding of TPVs with varying rubber to plastic ratios.
A fluoropolymer additive can be used to aid in the processability of resins and to improve some physical properties of the final part. The changes in processability and physical properties are explored. This study examines the effects of the base resin with a loading of fluoropolymer at 0.00% , 0.10%, 0.25%, and 0.50%. Several experiments were run to determine the effects of the fluoropolymer on processing and physical properties.
A comparison of the evolution of different color difference equations, and which ones are commonly used in plastic color measurement today.
We study the effect of the length of an alkane bridge on the equilibrium geometry of biphenyl. We rely on DF theory within the 6-31G* ab-initio framework to determine local energy minima and geometries. We discover that the effect of the bridge length is decidedly nonlinear.
Compression tests were carried out on Glass Mat Reinforced Thermoplastics (GMT) panels applying three ratios for thickness over width. Some panels showed a typical ductile splaying collapse mode with gross plasticity. The specific energy absorption of these panels was very high, and even higher than was found in literature for crush cones of this material. Aim is to formulate design rules for products that are composed of flat plane elements and are loaded on impact.
The effect of cooling rates (2-300degC/min) on the crystallinity, morphology and tensile properties of a selection of polyethylene and polypropylene resins was investigated using conventional and high speed DSC. Increasing cooling rate caused a decrease in percentage crystallinity. Mechanical analysis and polarised light microscopy showed related reductions in tensile modulus and strength and crystallite configuration.
The results of an interlaboratory test program conducted to assess the precision of the Practice Guide for High Strain Rate Testing of Polymers are summarized. Five polymers, HDPE, 30% short glass fiber-filled PA, PC/ABS, 40% long glass fiber-filled PP, and TPO, were tested at nominal plastic strain rates of 40/s and 400/s. The test results were used to generate inter and intralaboratory variability statistics that were incorporated into a precision statement for the Practice Guide.
Decorative woodgrain foils are important in the aesthetic appearance of UPVC profiles in the conservatory industry. Dark colours tend to absorb solar energy which causes distortion when reaching a critical temperature. This research has investigated three different foils subjected to simulated solar energy when placed on UPVC profiles using a specially designed test rig. This equipment failed to give results correlating to outdoor experience, therefore the test will be needed to be modified to be useful.
The effects of chain extension and branching on the properties of nanocomposites produced from recycled poly (ethylene-terephthalate) and organically modified clay were investigated. As the chain extension/branching agent, maleic anhydride (MA) and pyromellitic dianhydride (PMDA) were used. Both MA and PMDA improved the mechanical properties of the nanocomposite owing to the branching and chain extending effects that increase the molecular weight. However, PMDA gave better results at lower content.
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Brown, H. L. and Jones, D. H. 2016, May.
"Insert title of paper here in quotes,"
ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers
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