7:30 am – 11:30 am:
TH3-Composites: Processing and Properties, Natural and Biobased Composites-Room S320D
7:30 am – 8:00 am:
Damange Induced Surface Texturing of Short Fiber PDMS Composite Materials
Reza Rizvi, University of Toledo
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.
8:00 am – 8:30 am:
The Influence of Hygrothermal Aging on the Material Properties of Endless Fiber-reinforced Thermoplastics
Matthias Huettner, Paderborn University
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.
8:30 am – 9:00 am:
Influence of the Fiber-matrix-interaction on the Fracture Behavior of Regenerated Celluloase Fiber Reinforced Polypropylene
Jan-Christoph Zarges, University of Kassel
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.
9:00 am – 9:30 am:
Effect of Freeze-Drying on the Morphology of Dried Cellulose Nanocrystals (CNCs) and Tensile Properties of Poly (lactic) Acid-CNC Composites
Nicole Stark, USDA Forest Service, Forest Products Lab
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.
9:30 am – 10:00 am:
Effects of Tris (Vonylphenyl) Phostite on Mechanical Property of Poly (3-Hydroxybutyrate-co-3-Hydroxyhexanoate)
Takashi Kuboki, University of Western Ontario
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.
10:00 am – 10:30 am:
Potential of Biocarbon as Reinforcement for PBT in Automotive Applications
Boon Peng Chang, University of Guelph
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.
10:30 am – 11:00 am:
Crystallization Behavior of Poly (Lactic Acid) Composite Nanofibers by Annealing
Jian-hua Hou, Zhengzhou University
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.