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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Z-Fiber Process: It Means a Better Composite Reinforcement
Decades ago, Charles Macintosh embedded two layers of cotton fabric in natural rubber to make a raincoat. Not only he made a good raincoat, he opened-up future for fibre composites (FCs). Since FCs are made from layers of fabric glued together with resins, resins tend to break apart when stressed. Technically, this is known as delamination. It is possible to avoid delamination by adding extra thickness or by riveting. But these add cost and compromise strength. Resistance to delamination holds the key to a successful application.
Fulcrum Technology Boosts Thermoplastic Pultrusion Process
Composites are fabricated in a variety of processes. However, pultrusion process is favoured when high volume production of composite materials is demanded. Its ability to produce constant cross-section of proﬁles with little waste materials makes pultrusion one of the most cost-effective processes. For equivalent strength, pultruded ﬁnished products can be 50% lighter than aluminum and 80% lighter than steel. This is only part of the story.
Not Only Heat Resistant, Novel Plastic Composites Provide Impact Resistance
Technologically, "nanocomposite" is not a new word. However, it is currently a very exciting word for many researchers. Just like genome research. The recent development of nano-porous, nano-composites by researchers at Ohio State University adds a new dimension to heat resistant plastics.
Wood Plastic Composite
Wood and plastic are best friends these days. They can be combined to give the aesthetics of wood with the added durability of plastic. Termed as wood/plastic composites - WPCs' are a relatively new family of thermoplastic composites based on wood-fibres and the commodity thermoplastics. The polymers used for WPCs' are the high volume, low cost, commodity thermoplastics - polyethylene, polypropylene and PVC.
Advanced Simulation Methods for Prediction of Multi-Layer Non-Matching Fiber-Mat Applications In Resin Transfer Molding Process
The objective of this study is to use a simulation tool of resin transfer molding (RTM) process to get a comprehensive understanding of the permeabiliy measuring process. In order to varify the simulation tool’s capibility to simulate oil flow in non-matching fabric we build the mesh model of the measuring instrument cavity with the non-matching meshes in this study. This varifaciton case focuses on two properties of the RTM process, the arriving time and local pressure increasing trend in filling process. By using the simulation tools, we can observe the resin flow within the mold. The comparison between simulation and experiment result shows the reliability of simulation result. We expect that this study will help to clarify relevant issues and then reduce the trial-and-error time and materials.
Analysis of Contributive Forces In Intra-Laminar Shear of Continuous Fiber Reinforced Thermoplastics
Continuous fiber reinforced plastics offer excellent weight-specific properties, but their broad introduction to lightweight construction applications is still limited, among other things, due to insufficient accuracy of their processing simulations. A major reason for this is the limited availability of reliable material data and models. In this study, picture frame tests coupled with microscopic analysis are employed to separate the contributions of static weave deformation, lubricated rotational roving friction and roving compression and associated matrix relocation to the total intra-laminar shear forces. This approach allows for additional material insight and helps in developing suitable material models in an efficient way.
Bio-renewable Polyester/Graphene Nanocomposites
Bio-based polyesters are a new class of materials that are expected to replace their fossil-based homologues in the near future. In this study, nanocomposites of bio-renewable poly(ethylene 2,5-furandicarboxylate) (PEF) are reported with thermally reduced graphene (TRG) via melt blending method and compared with fossil-based PET/TRG nanocomposites. TRG was prepared from graphite oxide by simultaneous thermal exfoliation and reduction method and characterized. TRG was dispersed in PEF and PET via melt blending, and the nanocomposites were characterized for their thermal and morphological properties. The TRG exhibited strong interactions with PEF, increasing onset of thermal degradation by ~50°C and thermal degradation temperature by ~17°C. A strong nucleation was observed in both PEF and PET with the inclusion of TRG.
Computational Modeling of IR Heating of Composite-Material Parts
This paper explains the computational model developed in predicting the infrared heating of a composite material component. Computational Fluid Dynamics (CFD) technique is used in predicting heating behavior of a thermoplastic composite component. In-house testing facilities has been utilized to determine the radiation characteristic of the materials. The computational thermal model developed is validated by experimentally measured temperatures at key locations of sample plate during its heating. Comparisons between experimental data and numerical simulations showed good match between model & measurement. The developed model can be used as an effective tool in predicting the heater setting parameters for polymers/ composites heating in different application scenarios.
Experimental vs. Numerical Buckling/Post-Buckling Response of Cantilever Orthotropic Web Beams Under Tip Force
A combined numerical and experimental study of lateral torsional buckling of orthotropic rectangular section beam is presented. Pre and post-buckling analysis of beams is studied using Abaqus Riks analysis and compared with experimental results. Timoshenko’s solution with replacement stiffnesses is adopted to calculate the lateral torsional buckling load of six orthotropic beams. Four laminated composite beams with 0 degree layups and two beams with 90 degree layups are prepared in lab. Beams had different length-to-height (l/h) ratios ranging from 6.67 to 20 to study its effect on the critical load. All beams are assumed cantilever and tested under a concentrated load at the free end. Two laser pointers mounted horizontally at the free end are used to measure twisting rotation of beam section (β) for every load increment. Load vs. β plots are generated and compared with numerical and analytical results. The proposed experimental technique could be adopted to study lateral-torsional buckling response of laminated beams with arbitrary fiber orientations (generally anisotropic) under different load and support conditions. The technique also helps to generate load vs. lateral and vertical deflection simultaneously while measuring the section twisting rotation angle (β).
Improving Thermal Conductivity of CoContinuous Ternary Composites using Double Percolation Structure
The double percolation structure was used to produce thermally conductive polymeric composites including high density poly (methyl methacrylate) (PMMA)/polyethylene (HDPE)/ carbon nanofiber (CNF) and polypropylene (PP)/PMMA/boron nitride (BN) composites. Microscopy images showed that for both systems, most of fillers were in PMMA phase, confirming the hypothesis of the filler location by the thermodynamic theory. The thermal conductivity of the PMMA/HDPE/ CNF composite was higher than that of the HDPE/CNF and the PMMA/CNF composites with the same content of fillers loading when the CNF concentration got to 16 wt%. In addition, a similar phenomenon was also found when the BN concentration was above 10% in term of the PP/PMMA/BN composites. This study proved that double percolation structure was a useful way to improve the thermal conductivity of the polymer composites.
Keynote: Structural Characterization of Hybrid Composites with Graphene to Increase the Use of Light Weight
Injection molded composites have been used effectively in automobiles, but there is still a need for the development of lighter and greener materials. Hybrid composites, composites with multiple kinds and length scales of fillers, present the opportunity for exciting new material breakthroughs and the opportunity for finely engineer the performance of the manufactured materials. This study presents the structural testing results for a hybrid composite composed of a blend of glass fibers with graphene nano-platelets within a PA6 matrix. This blend is chosen to meet the high demands of the automotive industry for select under the hood applications. The results presented in this work demonstrate that the addition of less than 1% by mass of graphene nanoparticles can allow the reduction of glass fillers by nearly 25% with only a minimal reduction in performance while reducing the density increase relative to the neat polymer by nearly 20%.
Polyethylene/Graphene/Carbon Fiber Waste Hybrid Nanocomposites
With growing applications of polymer nanocomposites, the need to manufacture cost-effective nanocomposites is increasing. In this work, we report economical nanocomposites from polyethylene (PE) using graphene (GnP) and carbon fiber (CF) waste. The nanocomposites were prepared by simultaneously mixing PE, GnP and CF in a melt blender where CF appeared to be randomly dispersed along with GnP in PE matrix. A delayed crystallization was observed when nanocomposites were crystallized from the melts non-isothermally. The crystallization data was well explained using Avrami model. Moreover, the hybrid filler (CF and GnP together) showed better mechanical performance with increasing CF/GnP ratio.
Preparation of Cellulose Nanocrystal-Polypropylene Masterbatches by Water-Assisted Thermokinetic Mix
In an effort to avoid freeze-drying or solvent blending techniques and better leverage the fact that preparation of cellulose nanocrystals (CNCs) result in aqueous dispersions, we investigated a water-assisted melt compounding approach to disperse cellulose nanocrystals in polypropylene. A simple, water-based cetyltrimethylammonium bromide (CTAB) treatment of CNCs was used to reduce their hydrophilicity and inhibit hydrogen bonding. The aqueous suspension of treated CNCs was then blended with polypropylene in a thermokinetic mixer with various levels of a maleated polypropylene (MAPP) as a dispersing agent. CNC dispersion was evaluated by optical microscopy, scanning electron microscopy, and rheology. CTAB treatment alone was insufficient to provide good dispersion but dispersion improved greatly with increasing MAPP content. At the highest levels of MAPP, agglomerates were still present but nearly all were well below 1 µm in size. However, despite a CNC content of 8%, little rheological evidence of a network structure was found that would suggest well-dispersed nanocomposites.
Reaction Induced Phase Separation of High-TG Thermoplastic from Glassy Thermoset During Cure
Highly crosslinked, typically brittle epoxide/amine thermosets are commonly toughened with high Tg thermoplastics to afford phase separated morphologies that provide increased toughness without sacrificing high temperature performance. The typically low molecular weight thermoplastics are solubilized into the uncured thermoset system, and as the epoxide:amine reaction proceeds, the rapid molecular weight increase of the thermoset phase leads to a loss of solubility of the thermoplastic and initiates phase separation. The morphology development of reaction induced phase separation (RIPS) occurs between the initiation of phase separation and gelation. The development of these phase separated morphologies is altered by the cure prescription, the time between initiation and gelation, and breadth and depth of the rheological well during cure, all of which alter the growth and coarsening of phase separated domains. In this work, networks are prepared adjusting the loading level of thermoplastics to form a wide variety of network types, including droplet dispersed, network-like pattern co-continuous, and co-continuous networks. The morphology of networks is characterized using optical microscopy, scanning electron microscopy, and the phase separation and cure of the networks is monitored with rheokinetics studies. Cure rates of 1 and 5 °C/min are examined. Thermomechanical analysis confirms network type, and the effects of cure schedule, viscosity, loading level on RIPS morphology development is correlated to control phase separation during cure and target desired morphologies.
Reinforced Thermoplastic Containing Recycled Cardboard Fibers for Recreational Vehicles Applications
Lightweight reinforced thermoplastic (LWRT) composites are ideal for the recreational vehicle (RV) industry where traditional building materials are unable to provide the performance required. The LWRT composite is more durable and can be assembled for RV exterior and interior sidewall, ceilings, and roofs of both towables and motorhomes. Due to lighter weight, LWRT-based RVs may provide opportunity for towing with smaller vehicles, can be more fuel efficient, or can carry more cargo than traditional, wood-based RVs. This paper presents the initial investigations into the properties of LWRT composite panel produced from recycled (or old) corrugated cardboard (OCC) fiber, glass fiber and thermoplastic materials using a wet-laid process. New composite systems have been obtained varying the loading levels of OCC fibers (0, 10, and 20 %) and density of the resultant composite panels. The flexural test results showed panels made from OCC fibers were 30 to 50 % stronger and stiffer in machine direction (MD) and 30 to 40 % stronger and stiffer in cross-machine direction (CD) than the control composite material without OCC fibers. The sound absorption properties of the composite panels containing OCC fibers depend on the loadings of OCC fibers and the density of the panel, and 20 % OCC fiber-based composite showed best sound absorption results. The addition of OCC fiber resulted in a smoother surface and better aqueous glue compatibility than the control composite material. In addition, the flame retardancy results showed the addition of OCC fibers decreased the flame spreadability (FSI = 30) according to ASTM E84 standard. The results suggested that sustainable fibers could be used to produce strong and stiff composite panels with significantly lighter weight.
Surface Modifications of Cellulose Nanocrystals by Grafting Polylactic Acid via Polymerization—From Technique
Cellulose nanocrystals (CNCs) have drawn significant attention in recent years owing to their specific strength, renewability, widespread availability and relatively low cost. As a result, they have gained scientific and commercial interest and are currently produced at a pilot scale in many jurisdictions for several polymer composite applications. However, their poor dispersion in typically non-polar polymer resins limits the translation of their exceptional nanoscale properties to the macroscale. In this paper,we presenteda method for the surface modification of CNC by grafting polylactic acid(PLA) onto CNCs. The dispersibility of the native and surface modified CNCs(SMCNC)in rubber latex is compared and reported here. SMCNC showed a very good dispersibility in both water and chloroprene rubber(CR)which make it a good candidate for latex composite applications.
The Advanced Study of Hybrid Molding by CAE Simulation
Hybrid Molding is an emerging molding technology that is used in composite products. It has integrated molding characteristics, which can integrate multi-step process, save cost, reduce cycle time and make the product multifunctional. However, it is very hard to know what happened between composite sheet and melt during the process. In this study, we try to use CAE software to simulate the hybrid molding process. From the analysis results, it is possible to know the temperature change of composite sheet at any time and any place during the hybrid molding process, thereby helping to optimize the process and avoid possible problems.
The Influence of Recycling On Thermotropic Liquid Crystalline Polymer and Glass Fiber Composites
In this paper, high-performance thermotropic liquid crystalline polymer (TLCP)/polypropylene (PP) and glass fiber (GF)/PP composites were prepared by the injection molding process. Mechanical recycling of TLCP/PP and GF/PP composites consisted of grinding of the injection molded specimens and further injection molding of the granules. The influence of mechanical recycling on mechanical and thermal properties was investigated. In situ TLCP/PP maintains tensile modulus and strength during the recycling process, indicating the regeneration of polymeric fibrils at each reprocessing stage. GF/PP composite exhibits deterioration of mechanical properties after recycling because of fiber breakage during processing, which is a very common issue on reusing glass or carbon fiber reinforced composites. The experimental results reveal that the TLCP/PP composite has better recyclability than GF/PP and significantly enhances the mechanical properties of the blend.
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