Minh-Tan Ton-That

Morphological and rheological properties of PET/clay nanocomposites

This work investigates the effects of clay chemistry and concentration on the morphology and rheology of polyethylene terephthalate (PET)/clay nanocomposites. The complex viscosity of the PET nanocomposites exhibited a more solid-like behavior, in contrast to the matrix that had a frequency-independent viscosity. In addition, at high frequencies where the behavior of the matrix should be dominant, a lower complex viscosity of the nanocomposites was observed due to PET degradation in the presence of the organoclays. The high-frequency data were used to estimate the matrix degradation using the Maron–Pierce equation. The apparent molecular weight of the PET matrix was found to decrease from 65 kg/mol for the neat PET to 30 kg/mol for a PET nanocomposite containing 8 wt% Cloisite®; 30B. The apparent yield stress in the nanocomposites was determined using the Herschel–Bulkley model. Yield stress increased with the level of exfoliation and clay concentration, from ∼0 to 166 Pa when the clay concentration increased from 2 to 8 wt%.

A comparison of flax shive and extracted flax shive reinforced PP composites

In this study, flax shive (FS) and extracted flax shive (EFS) were fully characterized. The results showed that EFS presented lower noncellulose content, smaller porous tunnels and better thermal stability than FS. The 5 % weight loss temperature of EFS was over 200 °C, which can meet the requirements of the processing conditions for the natural fiber reinforced polymer composites. Consequently, the flax shive and extracted flax shive reinforced PP composites were prepared and characterized. It was found that the thermal stability of EFS/PP composites was better than that of FS/PP composites, and both FS and EFS behaved as nucleation agents, which could accelerate the crystallization process of PP in the composites. Mechanical test showed that EFS could be used as a reinforcing material for PP composite when compatibilizer was applied. The flexural strength and modulus of the composites containing 30 % EFS were about 8 % and 100 % higher than that of pure polypropylene, respectively.

Characterization of polypropylene composites reinforced with flax fibers treated by mechanical and alkali methods

Abstract Flax is a type of natural fiber widely used as reinforcing materials for polymer composites. The commercially available flax fibers in Canada consist of a significant amount of shive and other impurities, which could act as stress concentration regions to negatively affect the mechanical property of composites. In this study, the shive was manually removed from the commercial flax fibers by screening and combing to obtain different shive contents from 0 to 30 wt%. By contrast, the obtained flax fibers were further treated with alkaline solution. The fibers obtained from mechanical and alkali treatment were compared on their thermal and mechanical properties. As expected, it was found that the thermal stability and mechanical properties of the flax reinforced polypropylene composites increased significantly with the removal of the shive content. However, the alkali treatment on flax fiber did not further improve the composites properties. The possible reason was that the proper mechanical treatment (screening and combing) prior to alkaline treatment effectively loosened the fiber bundles for better single fiber separation in matrix and significantly removed the impurities, thus the effect of alkaline treatment did not become obvious.

Novel bio-nanocomposite hybrids made from polylactide/nanoclay nanocomposites and short flax fibers

This article aims to formulations and properties of novel hybrid biomaterials containing unique four-phase combinations of polylactide (PLA), nanoclays, flax fibers, and coupling agents. A PLA-grafted maleic anhydride (PLA-g-MA) masterbatch containing 10 wt% PLA-g-MA was obtained by reactive extrusion and was further used, after dilution, as a coupling agent. In addition, three PLA masterbatches containing 10 wt% of three different grades of nanoclays, one untreated nanoclay and two organonanoclays, were also compounded. In a subsequent extrusion step, the nanoclay masterbatches were diluted in PLA down to 4 and 2 wt% while simultaneously incorporating in each one 20 wt% of short flax fibers. Those bio-nanocomposites were compounded without and with an equivalent content of PLA-g-MA, that is, with 4 and 2 wt%, respectively, through the dilution of 10 wt% PLA-g-MA masterbatch. The effects of the nanoclay chemistries, PLA-g-MA, and of flax fibers presence on the properties of bio-nanocomposite hybrid materials were investigated. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, rheology, mechanical properties (tension, flexural, and Izod impact), and reprocess ability tests were used to characterize the bio-nanocomposite hybrid materials. In a second step, PLA-g-MA was replaced by an epoxy/styrene/acrylic copolymer for comparison purpose of their respective effect in bio-nanocomposite performances. Mechanical properties of bio-nanocomposites containing the second coupling agent were also evaluated. The effect of the epoxy/styrene/acrylic copolymer is discussed in comparison with the effect of PLA-g-MA.

Triticale straw and its thermoplastic biocomposites

Abstract The potential of triticale straw for the production of green composites based on polypropylene (PP) was evaluated. The composites were prepared by melt compounding of PP and chopped triticale straw (so-called triticale particles) using different formulations and triticale concentrations. The morphology and crystallization of the PP triticale composites were characterized by means of various techniques, including optical microscopy (OM), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). The composite mechanical performance was also evaluated. The results obtained demonstrate that, by simply adding triticale particles into PP, they play the role of a conventional filler that increases the modulus while reduces the strength. However, the developed formulation with the combination of coupling agent and reactive additive provides superior strength and modulus for the composites; thus, it can upgrade the triticale particles from filler to reinforcement category.

Biomaterial Value Proposition of Triticale

Cereal starch and straw are particularly good candidates for the manufacturing of environmentally friendly polymer materials, especially as replacements, either fully or partially, for traditional synthetic plastic products because of their renewal ability, biodegradability, and low cost. However, the use of cereal starch for the development of bio-based plastics has generated a competition with the human food supply and also created lots of concerns. The use of triticale starch for such purpose can ease those competition and concerns. In this chapter, the development of triticale starch and straw for plastic products and their potential applications are presented. For starch, the most promising venue that can bring rapidly triticale starch into plastic market is as direct use to replace partially traditional plastics and is mainly focused in this chapter. In this case, starch is plasticized and gelatinized (so-called thermoplastic starch or TPS) prior to replace conventional plastics. TPS are also blended with other plastics at a molten stage to produce homogenous blends. All these steps can be performed in one step using conventional plastic processing equipment in order to reduce energy consumption and production cost. The triticale starch morphology, the blending and processing ability into plastic products, and the formulation and the properties of the obtained triticale TPS-based plastic products, such as crystallization structure, morphology, rheological behavior, mechanical properties, and biodegradability are quite comparable to those of other TPS-based plastics made from other starch sources. Thus, it confirms the benefits of TPS-based plastics made from triticale are equivalent with those of other food-grade TPS-based plastics.

Wet process and exfoliation of clay in epoxy

A new approach for the preparation of epoxy-clay nanocomposite (ECN) was developed based on utilization of water remains in the clay treatment as a carrier to improve clay dispersion and intercalation/exfoliation. A novel type organoclay was prepared by combining short and long chain molecule intercalants. The short chain intercalant provides the functionality ready to interact with the polymer, while the long one helps keep clay layers apart from each other. The micro- and nano-structures, physical and mechanical properties, and fire resistance of ECN were studied. The results indicated that the use of wet process and clay modification facilitates the dispersion intercalation/exfoliation of clay, the interaction between clay and epoxy, and subsequently improves ECN mechanical properties and fire resistance. The drying, grinding and screening steps in the preparation of organoclay could be eliminated, thereby reducing energy consumption. This method allows the solvent free in the preparation of ECN, which requires considerable time and cost for solvent removing. This also reduces ECN’s environmental impact.

Synthesis and Characterization of Poly( ω -pentadecalactone) for Its Industrial-scale Production

The synthesis of biomaterial poly(ω-pentadecalactone)(PPDL) with yttrium isopropoxide as initiator in bulk was explored for its industrial-scale production. The weight-average molecular weight(

Physical and mechanical properties of thermoplastic starch/montmorillonite nanocomposite films

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