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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Paul Lem, Philip Bates, B. Baylin, J. Vanderveen, May 2012
This study examined the crystallization behaviour of polyamide 6 from post-industrial carpet waste (PIW6-GF) and virgin polyamide 6 (PA6-GF) - both reinforced with 30 wt% glass fibers. Neutron activation analysis was used to detect the presence of contaminants – principally TiO2, a common pigment in carpet fibers. Once the Ti content in the glass fibers was accounted for, the TiO2 contents in the resin fraction of PIW6-GF and PA6-GF were estimated to be 0.14% and 0% respectively. Differential scanning calorimetery (DSC) was performed to assess the overall level of crystallinity and rate of crystallization. Experiments showed that, regardless of the cooling rate, PIW6-GF started to crystallize sooner and at higher crystallization temperatures than PA6-GF. This was attributed to the presence of TiO2 acting as a nucleating agent. Towards the end of the crystallization process, the rate of crystallization for PIW6-GF was observed to slow down relative to PA6-GF. At the highest cooling rates attainable in the DSC (200 °C/min), PA6-GF completed crystallization before that of the PIW6-GF compound. This reduction in crystallization rate is again attributed to the nano-scale TiO2 that could be interfering with the later stages of the crystallization process. The total crystallinity of moulded parts was observed to be greater for PA6-GF than PIW6- GF. Dynamic mechanical thermal analysis (DMTA) was performed on both materials one minute after ejection from a 30°C injection mould. This allowed the capture of rigidity data during the cooling of the specimen at a constant temperature of 25°C. PIW6-GF parts exhibited significantly lower complex moduli during the 30 minutes after moulding. Interestingly, modulus values at 25°C of both materials measured one week after the moulding were equal. The slightly lower crystallinity and the slower rate of crystallization are the suspected causes of this stiffness difference.
Indah Widiastuti, Igor Sbarski, S. Masood, May 2012
In this article, numerical modeling is used to simulate the distribution of liquid diffusion in bioplastic material and to determine the hygroscopic stress. The material used is homogeneous PLA based plastic exposed to aggressive automotive liquid. An analytical one-dimensional liquid diffusion solution is also presented to consider liquid concentration distribution, which shows a remarkable agreement with numerical simulation results. The results display non-mechanical stress distribution inside the homogenous material due to non-uniform liquid concentration profile.
Electrospinning is a simple and versatile technique to produce fibers. This is accomplished by using an electrostatically driven polymer jet, which thins as it whips towards a grounded target. The micronsized fibers produced from electrospinning are typically collected in the form of a random mat. The size and disordered structure greatly limit their application for areas that require well aligned, highly ordered arrangements such as tissue growth, protective clothing, highly effective thermal insulation and filters for fine particles and reinforcing fillers. Process parameters were studied as a function of percent aligned fibers while microscopy was used to characterize fiber orientation.
Yu-Chih Liu, Chao-Tsai Huang, Tzu-Chau Chen, Tsung-Min Su, May 2012
Nowadays, with the increasing variety, complexity, and dimensional accuracy required for plastic products, CAE tools have been widely used in solving product design and manufacturing issues. However, lacking the consideration of process-induced effects on material properties in analysis, there is a significant deviation between the structural analysis results and the real product deformation. Besides, during the injection molding process performed for the production, it is essential to understand how the high pressure and high temperature plastic melt affects the mold surface for further investigation of the life cycle of metal mold. In this paper, we have proposed the simulation technology using Moldex3D-FEA interface to connect injection molding simulation (Moldex3D) and structural analysis (ANSYS). Using this technology, we can predict the injection molding product life cycle to cover injection molding process-induced variation on the part. At the same time, we also can evaluate how the process-induced effects will influence the mold metal life cycle. The results are very important for people to make the comprehensive consideration for full system lifecycle management.
Donald Bigg, Jonathan Macarus, Jack Price, Kenneth Heater, May 2012
Most commercial intumescent materials consist of hydrated ceramic compounds in a polymer matrix that expand due to water vaporization when heated above 100°C. There are many applications that could benefit from intumescent, fire suppressant/protection materials where the system operating temperatures exceed 100 °C (e.g., aircraft applications, power generation facilities, chemical and materials processing facilities, etc.). To meet this need, a high-temperature intumescent material was developed that will only intumesce when local temperatures exceed 200°C. Once the initiation temperature is reached, the high-temperature intumescent material rapidly expands to approximately 10 times its original thickness, creating a physical barrier that is robust enough to block the spread of fire.
Kazushi Yamada, Hiromi Matsuura, Ken Miyata, Yoshiaki Oya, Hiroyuki Hamada, May 2012
Heat sealed plastic bags are widely used in food packages, vacuum-seal, and so on. It is very important to understand about heat sealing properties of these packages to confirm the reliability for using with their products. This research studied the heat sealed properties and peelability of heat sealed poly(ethylene terephthalate) (PET) and oriented polypropylene (OPP) films with low- temperature seal layer (adhesion layer). The peel strength and fracture surface of heat sealed PET-based films and OPP-based films were investigated by using peel testing and SEM. The sensitivity for peelable of heat sealed package was investigated by brain wave measurement.
Chen Chen, John Quigley, Donald G. Baird, May 2012
Supercritical carbon dioxide was used with melt blending to form nanocomposites of polypropylene-organoclay. The collapse of the clays is investigated to further understand the processing limitations at high clay content. TEM and WAXD are provided to investigate these effects. It was found that shear forces result in collapse of the exfoliated structure in the composite. However, if the melt is not subject to enough processing, dispersion suffers. An intermediate solution must be determined.
Multi-walled carbon nanotubes (MWCNTs) were employed to improve the mechanical properties and electrical conductivity of syndiotactic polystyrene (sPS) aerogels by exploiting MWCNTs connectivity within the sPS network. The MWCNTs/sPS composite gels were prepared using thermo-reversible gelation process, whereby a hot solution of sPS and a dispersion of Kentera- modified MWNCTs were mixed and cooled at room temperature. Subsequently, MWCNTs/sPS aerogels were obtained by drying the gels under supercritical condition. The morphology of MWCNTs/sPS aerogels was investigated by scanning electron microscopy. The effect of MWCNTs on mechanical and electrical properties of the aerogels was studied. It was seen that the morphology of the aerogels remained almost unaltered with the introduction of MWCNTs. The compressive modulus of the composite aerogels increased compared to the native aerogels. The electrical conductivity enhanced significantly in the presence of a low volume percentage of MWCNTs. In addition, the electrical conductivity increased with compression.
Long fiber-reinforced thermoplastic (FRT) composites widespread use in automotive industrial fabrication is more of a requirement than short FRTs. Mechanical properties of FRT products are dominated upon fiber orientation within the part. Recently, we proposed a new mathematic orientation model for two considerations of the interaction and diffusion between the fibers and the fluid [U.S. Patent Pending in USPTO with Application No. 13/168,211 (2011)], namely, iARD- RPR (Improved Anisotropic Rotary Diffusion Model combined with Retarding Principal Rate Model). Following the well- known Jeffery Hydrodynamic Model, this iARD-RPR Model can well determine the evolution of orientation, suitably for long FRTs. In this study, we employed these models to simulate numerically that the long FRT fluid with polypropylene matrix flows through a center gated disk. As a result, predictions of shell-core-structure orientation distribution, through the thickness measured at three regions of the near-entry, the lubrication, and the near-end-of-filling along the radial direction of the disk, were in good agreement with experimental observations.
Cherie Fletcher, Vicki Flaris, Marén Gültner, Petra Pötschke, May 2012
Blending immiscible polymers with the addition of Nano- additives is a very suitable method for tailoring the properties of materials. Carbon nanotubes (CNT’s) have shown in recent years to be versatile filler influencing several properties favorably. One property of concern is electrical conductivity of multi-walled CNT’s (MWCNT’s) which can be transferred into insulating matrices by filler percolation. These materials will strongly influence modern electronics, energy delivery, and anywhere composite materials are used presently. Drop Shape Analysis using a variety of test liquids to gather mean contact angle measurements is combined with Owens-Wendt theory of surface energy determining values for each sample. Atomic Force microscopy permitted examination of localization properties of the MWCNT’s with and without reactive component directly impacting thermal conduction and ductility.
The continuous demand of high performance materials with key properties requires the optimization of polymerization and post-reactor treatment processes. A multiscale characterization approach including techniques such as rheology, fractionation and NMR has proven to be essential to understand the links between polymerization conditions, molecular structural properties and end performance. Rheology is a preferred candidate for analytical characterization, since its use provides combined knowledge on molecular characteristics and processability. A key parameter for the performance of materials during processing is the so-called LCB. Rheology, in particular methods exploring the longest relaxation mechanisms, is known to provide a significant insight into the type and amount of longer chains incorporated during polymerization. Most of the existing rheological parameters used by Industry and Academia, to correlate molecular structure and processability, are based on techniques that are often time consuming and which, for most of the cases, are only applicable to a given class of materials. The increasing need to reduce “time to market” requires the development of more sophisticated and efficient characterization tools. The combination of different non-linear viscoelastic methods presented within this work will provide further insight into the links between molecular structural properties and polymerization conditions. The use of the Large Amplitude Oscillatory Shear (LAOS) together with uniaxial extensional flow measurements can bring new understanding on the nature of the non-linear viscoelastic response of LCB materials and its correlation with molecular characteristics.
In this paper, polyamidoamine (PAMAM) dendrimer was grafted onto MWCNTs, then initiated the controlled PS polymerization by ATRP method. The grafted MWCNTs were charactered in detail. Furthermore, PS/grafted- MWCNTs nanocomposites were prepared by solution blending and applied for ScCO2 foaming process. Compared with the neat PS foam, this nanocomposites foam exhibits higher cell density and smaller cell size, indicating that the grafted MWCNTs employ excellent heterogeneous nucleating effect.
In this paper, mesoporous silica (SiO2) was prepared by the template polyamidoamine (PAMAM) dendrimers, then modified with polylactide (PLA) by solution blending. PLA/SiO2 composites were charactered in detail. The results showed mesoporous silica could improve the thermal stability of PLA. Microcellular foams of the composites were prepared by supercritical fluid carbon dioxide foaming and exhibited a higher cell density and smaller cell size compared with the pure PLA foam, indicating that the well dispersed SiO2 can act as a well heterogeneous nucleation agent.
David Kazmer, Stephen Johnston, Guthrie Gordon, Robert Gao, Zhaoyan Fan, Navid Asadiznajani, May 2012
A multivariate sensor is designed with a piezoelectric ring and an infrared detector for measurement of melt pressure and temperature. The infrared detector includes a thermistor for measurement of the mold temperature. The polymer melt velocity is estimated by inspecting the transient melt temperature signal. The melt viscosity is then estimated from rheological models as the slope of the melt pressure relative to the melt velocity. Experiments confirm the validity of the approach.
Injection molding process induced residual stress and the corresponding thermo-mechanical properties are passed to a structural analysis mesh with a point-based mapping mechanism and direct hook-up method into a structural analysis package. This mapping method enables a huge amount of data passing more accurately between dissimilar mesh models for the same parts without interface files, and the results calculated with different material and stress models used in molding simulations can be directly available to a structural analysis. Stress analysis on a buckle set is provided for engineering design and material selection consideration with the capability of this mapping mechanism.
Special applications in plastic engineering require new different polymers. Therefore new polymers and additives are constantly being developed. A lot of these special polymers are not available in data bases and cannot be used in simulation software. But it is becoming more and more important to know as much as possible about polymers in order to avoid problems in product development and the manufacturing process. So the polymers have to be tested. This paper shows a possibility of measuring points of a p-v-T chart and transforming them into a mathematic model to do simulation with the specific material afterwards.
Jodo Esteve, Sergio Amancio-Filho, Jorge dos Santos, Leonardo Canto, Elais Hage Jr., May 2012
Due to the increasing use of polymer-metal multi- material structures in automotive and aerospace industries, joining technology has grown in importance. Available techniques to join polymer-metal multi-material structures have been identified to be either too expensive, limited in performance or not environmental friendly. This work intends to investigate the feasibility of the new Friction Spot Joining technology on aluminum AA6181-T4 / poly(phenylene sulfide) laminate structures. Friction spot lap joints with high mechanical strength (29 MPa) were produced and investigated in terms of process temperature (average peak temperatures from 224 to 316 °C) microstructure and compared with similar joints available in the literature. Joints obtained by friction spot presented mechanical performance similar or superior to other available techniques used for joining polymer-metal structures. This is an indicative of the potential of this new technology to produce high performance metal-polymer multi-material structures.
We investigated the nucleation effect of well exfoliated and dispersed GO sheets on polystyrene scCO2 foaming. To get PS/GO nanocomposites with well exfoliated GO sheets, a method based on latex concept were employed. The characterizations based on XRD and TEM demonstrated the exfoliation and well dispersion of GO sheets in polymer matrix. The scCO2 foaming were carried out and the results showed the well exfoliated GO sheets could be a high efficient nucleation agent.
Weicheng Wang, Junjie He, Zhi-Qi Cai, Huifan Ye, Shouping Xu, Xiufang Wen, Jiang Chen, May 2012
Composites of Liquid crystalline epoxy resin(LCE) 3,3',5,5'-Tetramethylbiphenyl-4,4'-diyl bis(4-(oxiran-2-yl methoxy)benzoate) (M1) and glass fiber-reinforced nylon 66 (M2) were prepared by HAAKE 400P. Thermal properties of the composite were examined with TGA and measured with dynamic differential scanning calorimetry (DSC). It showed that the initial decomposition temperature of M2 increased by about 8°C by adding 7% wt M1, indicating the improvement of thermal stability. The melting point of composites decreased by 12°C compared to M2 as the content of M1 increased, showing the improvement of processing property
This paper investigates the differences in film properties between water-quench versus the traditional air-quench blown film process. The effect of process parameters such as water ring position, water temperature and annealing temperatures on the final film properties were studied. Barrier properties such as water-vapour transmission rate (WVTR) and oxygen transmission rate (OTR) were also compared. Results were correlated to the crystallinity differences observed between the samples using optical microscopy and WAXD.
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Any article that is cited in another manuscript or other work is required to use the correct reference style. Below is an example of the reference style for SPE articles:
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
Available: www.4spe.org.
Note: if there are more than three authors you may use the first author's name and et al. EG Brown, H. L. et al.
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