In this work, maleic anhydride (MAH) was grafted onto chlorinated polyvinyl chloride (CPVC) with high chlorine content (66 wt%) via in-situ chlorinating graft copolymerization (ISCGC) to obtain the material with improved mechanical strength, softening point, and thermal stability of the material. The structure of the graft product (CPVC-cg-MAH) was characterized by FTIR, 1 H NMR, GPC, and UV. CPVC-cg-MAH contains less vinylidene chloride (CCl 2 ) units and double bond than corresponding CPVC. Meanwhile, the number-average molecular weight (M n ) and weight-average molecular weight (M w ) of CPVC-cg-MAH are increased, but distribution of molecular weight (M w /M n ) is decreased. Then, the tensile strength and notched impact strength of CPVC-cg-MAH increased by 14.5 and 34.6%, respectively. Furthermore, the results of DMA, DSC, TG, and Vicat softening point showed that the loss peak of CPVC-cg-MAH was higher evidently than CPVC and moved to high temperature, the glass transition temperature (T g ) of CPVC-cg-MAH was consistent with CPVC, initial weight loss temperature, and maximum weight loss rate temperature of CPVC-cg-MAH increased by 7.2-C and 6.1-C, respectively, and the Vicat softening temperature of CPVC-cg-MAH increased by 15-C and up to 130-C.
This paper discusses the structure and mechanism of maleic anhydride (MAH) grafted onto isotactic polypropylene (iPP) via in situ chlorination graft copolymerization (ISCGC). The molecular structure of the grafted iPP was characterized using 1 H NMR and 13 C NMR spectroscopy, viscosity-average molecular weight and gel content. The structure of un-grafted MAH present in the reaction system was investigated using Fourier transform infrared spectroscopy in order to explore the grafting of MAH on iPP. The main side-reactions, including iPP chain scission and crosslinking, during the grafting reaction were explored. From the experimental results obtained, the reason for controlled macromolecular chain degradation and crosslinking of grafted iPP in ISCGC is proposed. Based on the structural characterization of the grafted polymer, the mechanism of grafting onto iPP obtained via ISCGC was deduced. Mechanical properties, both static and dynamic, of grafted iPP were also investigated and the results showed that the properties of the material changed due to grafted MAH.
The multi functionalization of isotactic polypropylenes (iPP) with glycidyl methacrylate (GMA) was carried out by in situ chlorinating graft copolymerization (ISCGC), in which chlorine (Cl 2 ) is used as a radical initiator as well as a radical scavenger. The molecular weight measurement indicates that functionalized iPP with controlled degradation could be obtained because the unstable radicals that induce iPP degradation could be terminated quickly by chlorine. Owing to the unique allyl-containing structure of GMA, multi functionalized iPP could be synthesized under the effect of chlorine, which contained both epoxy groups and C=C double bonds as well as trace amount of chlorine atoms in the functionalized polymer structure. The structure of both the functionalization polymer and homopolymer formed in this system were analyzed by FTIR and 1 H NMR. The mechanism of grafting reaction, iPP chain degradation, and GMA homopolymer formation scheme in ISCGC were proposed. The thermal properties of the functionalized polymer are also discussed.
This article discusses a convenient chemical approach named in situ chlorination graft copolymerization (ISCGC) to prepare epoxy functionalized isotactic polypropylene (iPP) with a unique structure. This method was carried out in the gas-solid state, and chlorine was used as radical initiator as well as terminate agent. The effect of influence factors on the structure of the functionalized PP was investigated, and it was determined by levels of grafted GMA moieties. The results showed that PP modified with GMA could obtain higher grafting level. Crystallinity and mechanical properties of the functionalized PP were also investigated. For the purpose of researching the reactivity of epoxy groups located at the grafted side chains, trichloroacetic acid and hydroxyl-terminated butadiene-acrylonitrile rubber (HTBN) were used as models to explore the ring open reaction of the epoxy groups of the functionalized PP. The structure and property of the modified PP that has undergone post-ring open reaction was characterized by FTIR, dynamic property analysis. The results indicated that epoxy groups of the graft side chains have successfully undergone ring open reaction in the presence of carbonyl and hydroxyl groups. Additionally, the compatibilization of PP with HTBN is enhanced after PP was modified by GMA.
Acrylic acid (AA) was grafted onto high-density polyethylene (HDPE) by in-situ chlorination graft copolymerization (ISCGC), yielding a graft copolymer composed of chlorinated polyethylene (CPE) as backbone and poly (acrylic acid) (PAA) as branch chains. The reaction process and the preparation of its carboxylated ionomers were studied. The structure of the graft copolymer and the ionomer were characterized by FTIR, gel permeation chromatography (GPC), and degree of grafting (GD). The influence of factors related to the main and side reactions, including the monomer concentration, chlorine contents of the product, and reaction temperature were investigated. Additionally, the effects of these factors on the reaction are described. The aim of the research was to investigate how chlorinated polyethylene grafted with poly (acrylic acid) (CPE-cg-PAA) and its sodium-salt ionomer could be prepared and their relative effect on thermal and mechanical properties.
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