The goal of this work is to investigate the effect of incorporating organoclays on the cross-link structure, morphology, and thermomechanical properties of cross-linked organoclay/polyvinyl chloride grafted with styrene and maleic anhydride (PVC- g-(St-MA)) copolymer nanocomposites (CPN). Cloisite30B (C30B) and Cloisite15A (C15A) organoclays were used for the preparation of cross-linked PVC- g-(St-MA) nanocomposites by the solution mixing route. The nanoclay content in nanocomposites varied from 0.2 wt% to 1 wt%. The chemical structure and interaction between PVC- g-(St-MA) cross-linked segments and nanoclays were studied by Fourier transform infrared (FTIR) peaks deconvolution method. FTIR spectroscopy suggested the lowest extent of hydrogen bonding interaction for C30B containing sample, which decreased with clay content increment. The morphology of nanocomposites was studied by X-ray diffraction and transmission electron microscopy methods. Morphological observation revealed a near to the exfoliation state for organoclays in PVC- g-(St-MA) nanocomposite containing 1 wt% C30B. However, C15A/PVC- g-(St-MA) nanocomposite (C15A-CPN) exhibited partially intercalated and agglomerated morphology. Differential scanning calorimetry examination was conducted to measure the glass transition temperature ( T g) of the segments. At the same clay content, the T g of the C30B containing nanocomposites were higher than that of C15A samples. The mechanical properties of these nanocomposites were also investigated. As a consequence, C30B-CPN showed improved mechanical properties compared to C15A-CPN and cross-linked PVC- g-(St-MA) samples.

In this work, styrene‐maleic anhydride (St‐MA) copolymer was successfully grafted onto poly(vinyl chloride) (PVC) by means of chemical method in cyclohexanone medium. In this manner, the effects of various parameters such as total monomer content, monomers ratio, and initiator concentration on the grafting percentage (GP) and acid value (AV) were examined. The graft copolymers were characterized by Fourier‐transform infrared and nuclear magnetic resonance spectroscopy methods. Afterward, the cross‐linking reaction was carried out through MA hydrolysis and condensation reaction between maleic acid and produced diamines, by toluene diisocyanate (TDI) at the presence of hot water. The results showed that the GP and AV of PVC‐g‐(St‐MA) copolymers were considerably higher than those of PVC‐g‐MA and PVC‐g‐St with significant molecular weight. A gel content of 56% was attained with 1 phr TDI in PVC‐g‐(St‐MA) copolymer. The glass transition temperatures and mechanical properties of PVC‐g‐(St‐MA) samples were increased compared to pure PVC. Cross‐linked PVC‐g‐(St‐MA) showed improved mechanical properties than other samples, but the glass transition temperature of PVC backbone in this cross‐linked copolymer was disappeared due to its heavily dense structure. J. VINYL ADDIT. TECHNOL., 25:377–384, 2019. © 2019 Society of Plastics Engineers

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