.vdf / Ctfe Copolymer Solubility And Its Structure Correlation Study

VDF/CTFE copolymer was used as binder in Polymer Bonded Explosives(PBXs). Monomer抯 chain segment ratio is usually characterized by measuring chlorine content. But it was found that the solubility of VDF/CTFE copolymer with similar chain segment ratio shows quite different. And the solubility of copolymer directly influences relative property of copolymer. Thus, the research on the influence factors and mechanism of copolymer抯 solution is a focus of general interest. Taking VDF/CTFE copolymer抯 solubility as starting point, this paper research on the coherent condition, characteristic chain segment structure composition and distribution, monomer chain segment arrangement, average molecular weight and the effects of their distribution on solution by modem available analyzing methods including: X-ray diffraction(XRD), nuclear magnetic relation(NMR), high resolution pyrolysis gas chromatography-mass spectrometry(Py-GC/MS) and gel permeation chromatography(GPC), and simultaneously by theoretical derivation and calculation. The results of research on dissolution state of VDF/CTFE copolymer in one same dissolution system show that their solubility are different. The solubility of VDF/CTFE( 1:1) copolymer is quite better than that of VDF/CTFE( 1:4) copolymer. In same resolution system, one kind of VDF/CTFE copolymer shows quite different solubility. The selected VDF/CTFE(1 :4) copolymer samples show different solubility in acetic ether. The coherent condition structure of VDF/CTFE copolymer is an important factor which directly influence copolymer抯 solubility, but not unique factor. To VDF/CTFE(l :4) copolymer samples from different batch, the effect of coherent condition structure on solution are also different. And it were found that not all VDF/CTFE(1 :4) copolymer抍rystal structure show the same resolution state. Therefore,so called �'olvent etching?principle which was used to get crystallinity is not suitable to VDF/CTFE copolymer system. Characteristic chain segment structure composition and distribution and monomer chain segment distribution in VDF/CTFE copolymer were effectively characterized and measured by using NMR and Py-GC/MS. Different chain segment structure composition and distribution exiting on different kind molecular chain segment of VDF/CTFE copolymer, In different dissolution parts of VDF/CTFE(1 :4) copolymer TI? VDF/CTFE #~1-I~iJI5i existing different chain segment composition and distribution. In soluble matter of dissolution system, distributes more monomer chain segments of vinylidene fluoride, and in insoluble matter of resolution system, distribution more monomer chain segments of trifluorochlorethylene. At the same time, the arrangement state of the two kinds of monomer in the two parts with different solubility are quite different. In soluble matter, two monomers mainly alternately arranged, similar to monomer chain segment distribution of VDF/CTFE(1 :1) copolymer. In insoluble matter, the chain segment structure distribution on copolymer molecular is characterized by repeating unit of tifluorochlorethylene. According to the above mentioned, the difference of composition and distribution of two monomers?chain segment on copolymer molecular is the basic reason caused their resolution difference. Average molecular and its distribution of VDF/CTFE copolymer is a reference...