This study reported the use of tetrabenzylthiuram disulphide (TBzTD) as a noncarcinogenic accelerator in a traditional sulfur curing system of epoxidized natural rubber (ENR)/nanosilica (nSiO 2 ) composites. ENR used in this work was synthesized via in situ epoxidation of natural rubber (NR) in the presence of performic acid generated from the reaction of formic acid and hydrogen peroxide at 50 ∘ C for 8 h to acquire the epoxide content of about 40 mol%. Accordingly, the resulting ENR was referred to as ENR 40. The curing characteristics, mechanical properties, thermal behaviors, dynamic mechanical properties, and oil resistance of ENR 40/nSiO 2 nanocomposites filled with three loadings of nSiO 2 (1, 2, and 3 parts per hundred parts of rubber) were investigated and compared with NR and neat ENR 40. The results revealed that the scorch and cure times of ENR 40/nSiO 2 nanocomposites were slightly longer than those of NR but slightly shorter than those of ENR 40. The tensile properties and tear strength for both before and after aging of all ENR 40/nSiO 2 nanocomposites were higher than those of ENR 40, while the glass transition temperature, storage modulus at −65 ∘ C, thermal stability, and oil resistance of ENR 40/nSiO 2 nanocomposites were higher than those of NR and ENR 40.
Recycled poly(ethylene terephthalate) (rPET), obtained mainly from postconsumer bottles, was melt-mixed with either poly(butylene adipate-co-terephthalate) (PBAT) or PBAT plus ultrafine wollastonite (5 lm) at different weight ratios on a twin-screw extruder and then injection-molded. Among the five rPET/PBAT blends (10-50 wt% PBAT) evaluated, the 80/20 wt% rPET/PBAT blend exhibited the highest tensile strength and degree of crystallinity, a slight increase in the tensile strain, and a remarkable increase in the melt flow index, but a lower tensile modulus and thermal stability with respect to the neat rPET. This blend was subsequently filled with four loading levels of wollastonite (10-40 wt%), where the tensile properties (modulus, strain at break, and strength) and thermal stability of the blend were all improved by the addition of wollastonite in a dose-dependent manner. Based on differential scanning calorimetry analysis, the crystallinity of rPET in the rPET/PBAT/wollastonite composites decreased in the presence of wollastonite, accompanied with a noticeable increase in the glass transition, cold crystallization, and crystallization temperatures, but only a slight change in the melting temperature was noted compared with those of the neat 80/20 wt% blend. Moreover, the addition of wollastonite at 30 wt% or higher showed a strong reduction in the melt dripping of the composites during combustion. J. VINYL ADDIT. TECHNOL., 00:000-000, 2015.
In this study, leather-like composites were prepared from natural rubber (NR) and two different types of leather waste, namely wet blue leather (WBL) and finished leather (FL). Compounding was carried out on an internal mixer and two-roll mill, and curing was further conducted on a compression molding machine. The effects of leather type and content from 20 to 80 parts per hundred of rubber (phr) on cure characteristics, mechanical properties (hardness and tensile properties) and thermal stability of the as-prepared composites were investigated and compared with those of the unfilled NR compound. The curing rate and crosslink density of all composites were found to be lower than those of the unfilled NR. All WBL-filled NR composites exhibited higher tensile strength than the unfilled NR, while all FL-filled NR composites had lower values. Meanwhile, the hardness and modulus at 200% strain of all composites were increased with increasing leather waste contents compared to those of the unfilled NR. The composites containing low WBL loadings (20 and 40 phr) demonstrated higher elongation at break over the unfilled NR, while the other composites exhibited lower values. Besides, the thermal stability of all NR composites was deteriorated, but still largely retained.
The objective of this work was to improve mechanical properties, thermal resistance, and biodegradability of poly(vinyl chloride) (PVC) by the addition of poly(lactic acid) (PLA), poly(butylene adipate-co-terephthalate) (PBAT), and wood flour (WF). The samples made from a mixture of PVC/PBAT exhibited the highest impact and tensile properties, while properties of the samples made from PVC/PLA had the highest flexural and thermal properties, PVC/PLA/PBAT mixed samples exhibited average mechanical properties. The addition of WF to all the blends increased impact strength, flexural properties, Young’s modulus, thermal resistance, and biodegradability of the samples in comparison to those of the neat PVC and its blends. Composite samples of PVC/PBAT/WF showed the highest impact strength, while PVC/PLA/WF composite had the highest flexural and thermal resistance. The samples manufactured from a mixture of PVC/PLA/PBAT/WF had the highest tensile strength and Young’s modulus. The overall results in this work suggested that the enhanced properties of PVC samples were strongly influenced by the compatibility between polymer blend matrix and WF particles.
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