Graphene oxide as a compatibilizer for polyvinyl chloride/rice straw composites

In this study, polyvinyl chloride (PVC)/rice straw (RS)/graphene oxide (GO) sustainable nanocomposite was prepared using the direct compounding method. Structural, morphological and mechanical properties of fabricated sustainable nanocomposites were compared with unfilled and RS-filled PVC compounds. Mechanical characteristics of PVC decreased with loading RS fibers. The main reason for the mechanical failure of PVC/RS composite is the incompatibility between PVC and RS fibers. GO nanosheets are used here to improve the compatibility between RS fibers and PVC macromolecules. Compared to the neat PVC, maximum strength of the RS/GO-loaded PVC composite increased up to 31%, with incorporating only 1 wt% of GO nanosheets. This enhancement in the mechanical characteristics of PVC/RS/GO nanocomposite can only be due to the role of GO nanosheets as a compatibilizer, as 1 wt% GO loading can only increase the mechanical strength of PVC compounds up to 9%. Fourier transform infrared spectroscopy results are used here to study the nature of these behaviors. It is suggested that the non-covalent and physical interactions between cellulose/hemicellulose portions of RS fibers and GO functional groups result in the enhancement of mechanical characteristics. Consequently, GO can be considered as a new compatibilizer for fabricating high performance PVC-based sustainable nanocomposites.

Influence of 3-aminopropyltriethoxysilane- graphite oxide composite on thermal stability and mechanical property of polyethersulfone

Graphite oxide (GO) was modified using 3-aminopropyltriethoxysilane (APTES) for the fabrication of sheet type APTES–GO composite. Then, this composite was incorporated into the polyethersulfone (PES) matrix to enhance the thermal and mechanical properties of this polymer. The influence of APTES–GO composite on the thermal stability and mechanical property of PES was evaluated. The surface modification of GO by interacting with APTES could be an effective method to improve the compatibility and dispersion of GO sheets within the PES matrix. In comparison with those of virgin PES and GO/PES composites, the thermal decomposition temperature of PES composites containing well-dispersed APTES–GO sheets increased by 18.7°C. The tensile strength, tensile modulus, flexural strength, and flexural modulus of PES composite reinforced with 1.0 wt% APTES–GO sheets were enhanced by 21.1%, 15.2%, 15.4%, and 12.8%, respectively. The enhancement in thermal stability and mechanical property of APTES–GO/PES composite can be attributed to the uniform dispersion of APTES–GO sheets in the PES matrix as well as the strong interfacial interaction between them.

Halogenated sunflower oil as a precursor for synthesis of polysulfide polymer

Polysulfide polymers usually are prepared by the reaction of different dihalide compounds with disodium polysulfides. In this field, dihalides are expensive and produced from halogenation of organic compounds by different methods with harsh conditions. To overcome this problem, in this work, sunflower oil as polyunsaturated oil was used as precursor to produce polyhalide compound. In this field, double bonds of oil were applied as functional groups to halogenate the sunflower via benzoyl peroxide-catalyzed reaction with hydrochloric acid. Also, Na2S3 was synthesized via the reaction between sulfur and sodium hydroxide. Then, halogenated oil was reacted with Na2S3 to produce sunflower oil-based polysulfide polymer. Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (1H NMR) were used to characterize the structure of sunflower oil and synthesized polysulfide polymer. The content of halogenation was also obtained via energy-dispersive X-ray spectroscopy (EDX). Thermal stability of synthesized polymer was determined by means of thermal gravimetric analysis (TGA) and glass transition temperature was investigated by differential scanning calorimetry (DSC).

Influences of sodium dodecyl sulfate on vulcanization kinetics and mechanical performance of EPDM/graphene oxide nanocomposites

In this work, influence of SDS presence on the physical interactions between EPDM macromolecules and graphene oxide functional groups are investigated.