SPE Library
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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Conference Proceedings
Synthesis, Characterization And Water Application Of Microcellular Injection Molded Ppgma/Mmt Nanocomposites
shyh-shin hwang, May 2018
This study investigated the effects of MMT (0.5, 1, 3 wt%) loading on thermo-mechanical, adsorption properties of microcellular injection molded PPgMA nanocomposites. The injection molding process was done by non-foam and microcellular molding. Results showed that the dispersion from TEM pictures, some of MMT are intercalated and some of them are exfoliated structures. This 0.5 wt % loading of MMT had the best tensile strength for solid molding while it is 1.0 wt% loading for microcellular molding on PPgMA material. This is the results of MA grafted PP. Tensile strength is related to the filler dispersion in the matrix. Good dispersion resulted in good tensile strength. It had the highest storage modulus for 0.5 wt% MMT loading PPgMA/MMT nanocomposites from the DMA test results. TGA results showed that thermal degradation can be increased with addition of MMT into matrix. SEM morphology showed that with addition of MMT, cell size decreased and cell density increased. Heavy metal adsorption test showed that MMT can adsorb Pb(II) more efficient than that of neat PPgMA.
Preparation Of Polypropylene Single-Polymer Composites With Graphene Nanoplatelets By Film-Stacking
Mingwang SHAO, May 2018
Polypropylene single-polymer composites (PP SPCs) are the materials where both the reinforcing phase and the matrix phase are PP. Graphene nanoplatelets (GNPs) have good mechanical properties because of its unique structure. In this study, GNPs were used as one kind of nanofiller to add in PP SPCs to improve its thermal properties and tensile properties. The PP-GNPs SPCs were prepared by film-stacking method. Differential scanning calorimeter experiments (DSC) were executed to determine the hot pressing temperature and investigate the thermal properties. Influences of the GNPs content on the tensile properties of PP SPCs were studied through the tensile tests. The results show that the melting peak temperature and tensile properties increase with the increase of GNPs content.
An Investigation Of Rheological Properties Of Polypropylene Single-Polymer Composites
Mingxing Yu, May 2018
Polypropylene single-polymer composites (PP SPCs), whose matrix and reinforcement came from identical type of polymers, were fabricated by an approach of applying undercooled polymer melt. The undercooling method could enlarge the processing temperature windows thus realize the fabrication of SPCs without destroy the reinforcement structures. Rheology could be used in the processing of the SPCs, however there is little investigations. This work was done with the aim to investigate the effect of undercooling compaction temperature from 125 oC to 145 oC on rheological properties of PP SPCs by dynamic rheological measurements. The linear viscoelastic range (LVE) was measured for strain sweep. And it was found that complex viscosity of PP SPCs increased as the temperature increased, whereas the storage modulus decreased during frequency sweep. Moreover, the photography of morphology before and after tests revealed a positive correlation between the degree of shrinkage and the compaction temperature. Overall, the effects of temperature on rheological and morphology properties of PP SPCs are strictly dependent upon the molecular structure parameters.
Influence Of The Fiber-Matrix-Interaction On The Fracture Behavior Of Regenerated Cellulose Fiber Reinforced Polypropylene
Jan-Christoph Zarges, May 2018
This investigation focuses on the fiber-matrix-interaction of man-made cellulose fibers (RCF) in a PP matrix with an additional MAPP content using an energetic evaluation of the single fiber pull-out test (SFPT). Furthermore glass fibers were characterized for reference purposes. With the SFPT the interfacial shear strength (IFFS) and the critical fiber length (lc) as well as the consumed energy of a fiber pull-out and a fiber rupture were determined. In a following step the resulting values of lc were related to the fiber length distribution in injection molded specimens. It was shown that, based on the longer RCF in the specimen, theoretically more fiber ruptures appear in the RCF composites. But the RCF composites also contain a higher number of long fibers, consuming a higher amount of energy by being pulled out during a composite failure. The length-dependent consumed energy of a fiber pull-out was increased by using MAPP but simultaneously the critical fiber length was significantly reduced.
Suppression Of Necking In Lldpe/Seps Rubber Bilayer Laminates
Sachin Velankar, May 2018
Semicrystalline plastics often show necking and drawing behavior in tension. In contrast, rubbery materials do not show necking, but instead stretch homogeneously. We examine the behavior of bilayer laminate composites of linear low density polyethylene (LLDPE) and styrene-ethylene/propylene-styrene (SEPS) rubber to test the extent to which the SEPS can modify the necking behavior of the LLDPE. Video recordings of tensile tests on dog-bone shaped samples were analyzed by a Digital Image Correlation (DIC) technique to quantify the degree of non-homogeneity in deformation. The LLDPE showed severe necking with a natural draw ratio exceeding 5. Upon bonding it to a rubber layer, the natural draw ratio reduced significantly. With a sufficiently large SEPS thickness, the neck was almost completely eliminated and the sample reverted to nearly-homogeneous deformation. We present a simple 1D model of the mechanics of the bilayer laminate in which the force within the bilayer is treated as a sum of the force of a Mooney-Rivlin rubber layer and an elastoplastic layer. The model predicts the decrease in natural draw ratio and the elimination of necking as rubber thickness increases, consistent with experiments.
Isolating The Effect Of Polymer-Filler Interaction On Polymer Composite Property Enhancement: The Example Of Polypropylene/Halloysite Hybrids
Tong Wei, May 2018
We prepare polypropylene (PP) composites with both pristine halloysite nanotubes (p-HNT) and PP grafted halloysite nanotubes (PP-g-HNT) using two processing techniques, solid-state shear pulverization (SSSP) and melt mixing. We address the role of isolated polymer-filler interaction effects on polymer nanocomposite property enhancement at similar, high levels of filler dispersion. As demonstrated by microscopy and rheology, nanocomposites prepared by SSSP with different fillers have very similar, well-dispersed states, eliminating differences in dispersion as a factor in property enhancements. The well-dispersed PP/PP-g-HNT nanocomposites exhibit a broad range of properties that are superior to those of PP/p-HNT, including tensile strength, PP non-isothermal crystallization onset temperature, and isothermal PP crystallization half-time. However, the Young’s modulus is the same regardless of filler modification. Only superior filler dispersion contributes to Young’s modulus enhancement in nanocomposites.
Crystallization Behavior Of Poly(Lactic Acid) Composite Nanofibers By Annealing
Jian-hua Hou, May 2018
Poly(Lactic acid) (PLA) is a typical biodegradable and bioabsorbablesemicrystalline material and has drawn extensive attention due to its excellent biodegradability, biocompatibility and mechanical properties. The semicrystalline PLA has a low crystallinity and the crystallite is imperfect which affects the properties of PLA parts. In this study, the effect of annealing on the composite nanofiber of PLA and graphene oxide(GO) and carbon nanotubes(CNT) is investigated. Nanofibers of PLA, PLA/GO and PLA/CNT are successfully prepared. A serials of characterization on crystalline morphology on the nanofibers suggest that the addition of GO and CNT enhance the crystallization of PLA and the enhancement effect of GO is better than that of CNT. Annealing improves the degree of perfection and crystallinity of PLA nanofibers. With the increased annealing temperature, the improvement becomes more significant. The results reveal that annealing is a favorable method to tuning the crystalline of PLA and its composite nanofibers, which allows to optimize other properties for the nanofibers.
High Confidence Performance Predictions For Hybrid Thermoplastic Composite Applications
Subhransu Mohapatra, May 2018
Multi-material hybrid structures that blend continuous fiber thermoplastic composites with lower-cost options such as chopped fiber thermoplastic composites and metals is an attractive proposition for many industries, due to the potential dual benefits of lower weight and cost. High confidence in performance predictions is one of the key enablers to convert this potential into successful industry adoption. However, chopped and continuous fiber thermoplastic composites pose numerous challenges for accurate predictions, due to the inherent complexity of the material behavior. To establish confidence in predictions, a test component was designed that can be produced in a representative production process and can validate all of the many different composite failure modes. Predictive simulation procedures in multiple industry-standard commercial software platforms were established to cater for the needs from multiple industries and loading scenarios. Component level static and dynamic tests were performed on the test component and were compared with the simulation results to validate the methodology. Excellent correlations between the simulation model and the physical test results paves the way for using the methodology for yet-to-be-designed components.
The Influence Of Hygrothermal Aging On The Material Properties Of Endless Fiber-Reinforced Thermoplastics
Matthias Huettner, May 2018
The ambition of developing innovative and technically high-quality products is one of the main reasons for the growing use of fiber-reinforced plastics (FRP) in industry. In particular, the opportunity to combine lightweight construction with a high degree of design freedom and functional integration leads to the preferred use of composite materials in the automotive and aerospace industries.During the operation time the composite parts are exposed to continuously changes of environmental influences which lead to aging of the polymers. This includes frequent temperature changes, dampness, saline media and mechanical loads for instance. The aging effects, caused by the interaction with the surrounding media, result in various changes of the material properties. Strength losses, embrittlement, degradation of the molecular weight or optical changes are some examples which can occur during the aging process and may induce a prematurely failure of the composite parts.In order to predict the life time of those components, the effects of the aging process and the influences on several material properties have to be known. Hence, in the following the environmental aging of a woven fabric reinforced, a short glass fiber-reinforced and an unreinforced polyamide 6 will be investigated and the influences on the material properties will be characterized.
In-Situ Vitamin C Reduction Of Graphene Oxide For Preparing Flexible Tpu Nanocomposites With High Dielectric Permittivity
Han-xiong Huang, May 2018
Flexible thermoplastic polyurethane/reduced graphene oxide (TPU/rGO) nanocomposite sheets are prepared via in situ vitamin C reduction. X-ray photoelectron spectroscopy spectra suggest a successful reduction of the GO by vitamin C, which can enhance the interfacial polarization ability of the resultant rGO layers. X-ray diffraction patterns and transmission electron microscopy image indicate a well exfoliation of the rGO layers in the TPU matrix. This results in the formation of a rheological percolation structure in the nanocomposite with 0.75 vol% rGO, as suggested by the rheological properties. The enhanced interfacial polarization ability and the formed percolation structure of the rGO layers in the TPU matrix allow for constructing a large network of micro-capacitors. Thus high dielectric permittivity (ε′ = 151 at 1 kHz) is obtained for the nanocomposite sample with only 0.75 vol% rGO.
Draping Behavior Of Uni-Directional Tape Laminates – Experimental And Numerical Studies
Sandeep Kulkarni, May 2018
Today continuous fiber thermoplastic composites are used in various applications across the industry due to its excellent mechanical properties, which offer significant weight saving potential. In addition, thermoplastic composites are well suited for mass production and easily integrated in a hybrid overmolding processes. This enables the industry to manage cost while delivering performance. Forming or draping is an important step in the manufacturing of continuous fiber prepreg or tape based thermoplastic material forms. Different studies indicate that forming of multi-layer unidirectional (UD) laminates may result in out-of-plane wrinkling and in-plane fiber misalignment. Thus, understanding the forming behavior and having a simulation method in place for its prediction is essential for widespread acceptance of this new material. This paper presents experimental forming studies on multi-layer GF-PP UD thermoplastic composite laminates. The influence of the tool geometry and the laminate layup on forming behavior are studied. The results show that the current GF-PP UD composites are easy to shape, resulting in a large processing window. However, in some cases process induced defects arise, such as out of plane deformation, fiber waviness, ply splitting, bridging, etc. whose influence on part performance needs to be assessed and quantified. Forming simulations are performed on UD tape based laminate composites in PAM-FORM software using a visco-elastic material model, dedicated to continuous fiber composites. Numerical studies show that the predicted process induced defects such as fiber waviness and wrinkling patterns are in good agreement with experiments. With increased confidence on such a computational framework, thermo-forming simulations can help identify critical spots in the product and process design at an early stage and reduce costly product development times. Keywords— Continuous fiber composite, Unidirectional composite, Thermoforming, Wrinkling, Ply splitting, Marcelling, Numerical simulation
Effect Of Freeze-Drying On The Morphology Of Dried Cellulose Nanocrystals (Cncs) And Tensile Properties Of Poly(Lactic) Acid-Cnc Composites
Nicole Stark, May 2018
Cellulose nanocrystals (CNCs) are routinely produced as aqueous suspensions. These are then typically freeze-dried in order to be added into polymeric composites using melt-blending. However, dispersing freeze-dried CNCs into hydrophobic polymers is a challenge. In this study, our objective was to advance our understanding of the impact of freeze-drying methods on the morphology of dried cellulose nanocrystals (CNCs), and on the tensile properties of the resulting PLA-CNC nanocomposites. CNCs were prepared as aqueous suspensions with 10.7% solids content using a sulfuric acid method, and freeze-dried using a procedure typical to our laboratory. In addition, the CNC aqueous suspension was diluted to 1% and directly freeze-dried or sonicated for 10 or 30 minutes, flash frozen, and freeze-dried. The particle size and morphology of the CNCs before and after freeze drying were determined by microscopy. CNCs were then incorporated into PLA using melt-blending extrusion and injection molding. The PLA-CNC nanocomposites were tested for thermal and mechanical properties. Before freeze-drying, CNCs were nano-scale, while agglomerations were observed after freeze-drying. The agglomerate sizes were reduced with dilution and/or increased sonication time, with fibrillar structures observable after sonication. PLA-CNC composites containing CNCs that were subjected to dilution, sonication for 30 minutes, flash frozen and freeze-dried had higher tensile modulus and strength compared with the other treatments.
Property Characterization Of Injection Molded Hybrid Composites
Gangjian Guo, May 2018
Hybrid composites with two or more fillers offer advantages such as improved mechanical properties and balanced performance/cost ratio. They have been increasingly used in many industries such as automotive and aerospace industry. The properties of hybrid composites largely depend on the matrix material, the type and the content of fillers, the filler distribution in the matrix, and the interfacial bonding between the fillers and the matrix. Wood fiber (WF), glass fiber (GF), and carbon fiber (CF) have been used in a variety of polymer composites applications. This study applies the injection molding process, and investigates the tensile properties, water absorption, burning behavior, and surface roughness of pure polypropylene (PP), PP/WF composites, PP/GF composites, PP/CF composites, PP/WF/GF hybrid composites, and PP/WF/CF hybrid composites. This study would provide guidance for choosing composites for different applications in consideration of cost and performance.
In-Situ Synthesis Of Poly(Ethylene Terephthalate) Graphene Nanocomposites
Vahid Shabafrooz, May 2018
Fabrication of graphene-based poly(ethylene terephthalate) (PET) nanocomposites through in-situ polymerization is demonstrated. With the goal of improving the incorporation and dispersion of graphene in the PET matrix, an ultrasonic exfoliation method was employed in ethylene glycol (EG), a raw material used in PET synthesis. The graphene EG dispersions were used as precursors to fabricate PET nanocomposites. Transmission electron microscopy (TEM) was used to evaluate the level of exfoliation of graphene in the dispersions. Mechanical testing showed at 2 wt. % concentration of graphene, the elastic modulus and the tensile strength of PET increased by 22% and 10%, respectively. Differential scanning calorimetry (DSC) measurements were performed to evaluate the percent crystallinity, and it was observed that addition of graphene at 2 wt. % increased the crystallinity of PET by 33%. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to study morphology and microstructure of the PET nanocomposites, respectively.
Virtual Characterization Of Prepreg Platelet Length Effect On Tensile Properties Of Coupons With Stochastic Morphology
Sergey Kravchenko, May 2018
Progressive failure analysis is herein used to study the damaged deformation up to ultimate failure in prepreg platelet-based tensile coupons with stochastic morphology. Computational damage mechanics approaches (continuum and discrete) are utilized for constitutive modelling and addressing complex interacting/competing damage mechanisms. The developed failure analysis allows for virtual characterization of how the composite structure details, meaning the platelet geometry and system morphology (geometrical arrangement and orientation distribution of platelets), define the effective properties of a platelet-molded composite system, its stiffness, strength and variability in properties.
Effects Of Tris(Nonylphenyl) Phostite On Mechanical Property Of Poly(3-Hydroxybutyrate-Co-3-Hydroxyhexanoate)
Takashi Kuboki, May 2018
This study investigates the effects of tris(nonylphenyl) phostite (TNPP) on the mechanical property of bacterial polyester, poly(3-hydroxybutyrate-co-hydroxyhexanoate) (PHBH). Two types of PHBH were used: One has 5.6 mol% of 3-hydroxyhexanoate (3HH) (PHBH5.6) and the other has 11.1 mol% of 3HH (PHBH11.1). PHBH/TNPP samples were prepared by melt-compounding and injection molding, and TNPP content varying from 0 to 3wt%. Tensile test results suggested that the addition of TNPP slightly decreased Young’s modulus and strength of both PHBH5.6 and PHBH11.1. However, the addition of TNPP influenced strain at failure and fracture energy of the two types of PHBH in a different manner, that is, significant increase of strain at failure and fracture energy for PHBH11.1, in contrast to decrease of strain at failure and fracture energy for PHBH5.6. The results suggest that TNPP can be used as an additive to significantly improve ductility and fracture energy of PHBH with high 3HH content.
High Fracture Resistance, Filler Adhesion And Dispersion In Epoxy Carbon Nanofiber Composites
Muhammad Anwer, May 2018
This study evaluates the morphological, fracture and mechanical characteristics of composites of epoxy with carbon nanofibers (CNFs). These composites were prepared via modified solvent exchange process resulting in significant filler dispersion and matrix filler adhesion as evidenced from the SEM micrographs. Composites with 0.1, .5, and 1t% fillers were evaluated. The crack resistance, KIC of these composites with just 1wt% CNF is more than 2 times that of neat epoxy. The tensile strength and modulus of the epoxy CNF composites show more moderate changes with increase in the CNF content.
Damage Induced Surface Texturing Of Short Fiber PDMS Composite Materials
Reza Rizvi, May 2018
Damage induced surface texturing (DIST) is a newly developed technique based on fiber de-bonding and pullout in composite materials. This method consists of two stages - in the first stage fibers are aligned longitudinally in the compliant material and during the second stage, the composite is cut perpendicular to the direction of aligned fibers to generate the textured surface. Characterization of the produced composite demands thorough investigation of process parameters like matrix and fiber stiffness, fiber geometry, fiber volume percent ratio. In the present study, surface textured composites are produced using polydimethylsiloxane (PDMS) as the compliant material, which has been reinforced with various fibers to manipulate the surface functionality of the cut surface. The results indicate that increasing fiber elastic modulus, fiber diameter and fiber tensile strength will increase de-bonding and pullout length. In contrast, enhancing critical strain energy release rate (G2c), matrix modulus, the friction coefficient between fiber and matrix and fiber/matrix misfit strain can decrease de-bonding and pullout length. Furthermore we show that increased de-bonding and pullout lengths impart the generated surfaces with increased hydrophobicity.
Acoustic And Flame Retardant Light Weight Reinforced Composite
Ruomiao Wang, May 2018
Acoustic performances are commonly required by different industries, such as building and construction, automotive and others. Based on the specific application, the requirements and also test methods can be significantly different from one area to another. Flame retardant performance represents another type of commonly specified requirement as well, and this kind of performance also shows significant dependence on test methods, which are determined by the applications. In this paper, two new grades of light weight reinforced thermoplastic (LWRT) composites are introduced. Acoustic performance tested by ASTM E1050 and ASTM C423-17 methods, and flame retardant (FR) performance tested by ASTM E84 and SAE J369 methods will be discussed. The physical properties and mechanical properties of the new composites will also be compared with the standard LWRT materials.
Potential Of Biocarbon As Reinforcement For Pbt In Automotive Applications
Manjusri Misra, May 2018
Over the last few decades, the move towards more sustainable development and environmental protection has offered many opportunities to develop both biodegradable and biobased composite materials with excellent performance. This new class of materials promises to enable the circular economy concept and sustainable development for our future. In this work, the properties comparison between renewable bioresourced fillers and synthetic conventional fillers were presented and discussed. This works reveals that biocarbon-filled poly(butylene terephthalate) (PBT) hold very high potential to replace existing mineral filler-filled PBT composites in automotive applications. With high biobased content, lower density and cost, it is obvious that the biocarbon filler can be used as a substitute for conventional fillers to develop more eco-friendly products.
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