Natural fibers are seeing increased use in composite applications due to their reduced cost, low density, and environmental benefits (more sustainable and lower carbon footprint). Although many natural fiber systems have been examined over the last decade, there have been relatively few studies which have compared a variety of fiber types and processing methods directly in the same experimental set. In this study, natural fiber composites made from low density polyethylene (LDPE) and a variety of Canadian based fiber feedstocks were examined including hemp bast, flax bast, chemically pulped wood, wood chips, wheat straw, and mechanically pulped triticale. The effect of fiber type, fiber fraction and maleic anhydride polyethylene (MAPE) coupling agent on the mechanical properties and long-term moisture absorption behavior was quantified. In general, addition of natural fiber to LDPE results in an increase in modulus (stiffness) with a corresponding loss of material elongation and impact toughness. Of the fiber types tested, composites made from chemically pulped wood had the best mechanical properties and the least moisture absorption. However, the use of MAPE coupling agent was found to significantly increase the mechanical performance and reduce moisture absorption for all other natural fiber types. V C 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 969-980, 2013
The main goal of this research is maximizing the utilization of renewable materials in both the matrix and reinforcement, more importantly exploitation of waste material for biocomposite development and evaluating the mechanical, thermal and water resistance performances. Woven roving and chopped strand mat fiber glass, and hemp fiber mats are incorporated to an epoxy resin based matrix cured with novel hydrolyzed specified risk material (SRM) extracts. Aminophenyl sulphone (APS) is used as a control crosslinking agent for the epoxy resin. Results show that the biocomposites developed in this research exhibit promising flexural strength, tensile strength and tensile modulus; despite relatively poor moisture resistance. The use of waste protein hydrolyzate extracts, hydrolyzed proteins, as crosslinking agent of epoxy resins in making biocomposites is novel and promising and results can be extended to other proteinaceous biomasses as curing agent of epoxy resins.
We propose an entropic measure to assess color homogeneity as well as deviations from a standard/ideal color. We illustrate the concept by analyzing samples obtained in a single screw extruder by mixing blue and yellow polymer pellets. Alternatively the proposed technique can be employed to assess the efficiency and degree of distributive mixing attained in polymer processing equipment.
Abstract.Mixing is an important component in most processing operations including but not limited to polymer processing. Generically, mixing refers to the system capability to reduce composition nonuniformity. Since the entropy is the rigorous measure of disorder or system homogeneity, we will explore in this presentation various ways to employ the entropy to characterize the state of mixing in a multi-component system. The various species can be initially present in the system or they can evolve as a result of a dispersive mixing operation involving a cohesive minor component.
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