| Poly (vinyl chloride) was a versatile plastic with high production and extensive applications, and it had many advantages such as flame resistance, abrasion resistance and reagent resistance and so on. But, the PVC is sensitive to thermal and its crytallinity is low.So the nomal PVC materials had some restriction in applications due to its poor mechanical property and heat resistance.Therefor, crystallization modificated PVC was a research development to the increase its performance.Up to now, people has not widely understand the crystallization behavior of PVC, but the crystallization and its effects of on the properties attracrted much attentions. In this paper, side chains of crystalizable linear alkyl esters were introduced on the PVC backbone by means of grafting, the effects of graft degree and length of side chains on thermal and mechanical properties of PVC were made a preliminary study.In this article, PVC was modified through grafting monomer by iodination. A series of comb-like grafted PVC with crystalizable side chains were synthesized by nucleophilic substitution, using carboxylate with linear alkyl groups (containing even number of carbon atoms from 12 up to 20) as raw materials, which were named as PVC-C12, PVC-C14, PVC-C16, PVC-C18 and PVC-C20 respectively.We did some researches about the effects of the reaction conditions on iodination reaction and grafting reaction. We knew comb-like grafted PVC could be obtained at 70℃with reaction time and content of monomer(molar percent)were 9h and 50% respectively, which was thought to be the best reaction conditions. Structures and functions of the comb-like grafting PVC were investigated by FT-IR, 1H-NMR and GPC, furthermore, the effects of reaction time on graft degree were discussed. A new stronger peak(C=O) at 1730cm-1 appeared in FT-IR., which can be assigned to the carbonyl group in side chains of comb-like grafted PVC. Two new peaks at 8=0.86-0.89ppm and 1.25ppm in 1H-NMR spectra which were attributed to shift of-CH2-CH3 and-CH2-CH2-CH2-COO- from the alkyl side chains of comb-like PVC. The Mn and Mw of comb-like grafted PVC were increased and the molecular weight distribution was reduced. These results indicated that comb-like side chains were grafted on PVC successfully.In addition, thermal and mechanical properties of comb-like grafting PVC were studied by XRD, TG, DSC and Electronic universal testing machines, the effects of graft degree and length of side chains on crystallization and mechanical properties of comb-like grafted PVC were discussed. The results showed that the side chains in comb-like grafted PVC were able to crystallize, and increasing the ratio of graft degree, the fusion enthalpy of PVC-C12, PVC-C14 and PVC-C18 and melting temperature increased, while the melting range narrowed.Comb-like grafted PVC had higher thermal resistance than PVC. The tensile strength and elongation at break of PVC-C12 were lager than PVC with the increasing of graft degree. With the increasing of graft degree, the tensile strength of PVC-C14 and PVC-C16 increased at first and decreased afterwards, but it was higher than PVC, while the elongation at break of them decreased even lower than PVC; The tensile strength of PVC-C18 and PVC-C20 increased straightly, but the changing pattern of the elongation at break were just opposite. When graft degrees were close, crystallinity of side chains of comb-like grafted PVC was enhanced with the length of the side chain increasing, and the tensile strength increased gradually, while elongation at break increased at first and decreased afterwards.
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