Microphase vs. macrophase formation in homopolymer/block copolymer blends with exothermic interaction
Microphase vs. macrophase formation in homopolymer/block copolymer blends with exothermic interaction
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具有放热相互作用的均聚物/嵌段共聚物共混物中微相与宏观相的形成
DOI：
10.1016/0032-3861(95)93653-4
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发表时间：
1995
期刊：
影响因子：
4.6
通讯作者：
S. D. Hudson
中科院分区：
文献类型：
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作者：
A. Adedeji;A. Jamieson;S. D. Hudson
在溶剂浇注均聚物/嵌段共聚物共混物中，尽管存在放热混合，但微相和大相的形成取决于均聚物和嵌段共聚物的不相容链段的相对分子质量。研究了以甲乙酮为溶剂的聚氯乙烯(PVC)与聚(甲基丙烯酸丁酯-b-苯乙烯)嵌段共聚物(PnBMA-b-PS)的二元共混。通过改变相对分子质量，我们改变了控制相形态的热力学产物N-χ聚氯乙烯/聚苯乙烯。式中N=NPVCNPS/NPVC12+NPS12)2，其中NPVC和NPS分别表示聚氯乙烯和聚苯乙烯嵌段共聚的聚合度，χ聚氯乙烯/聚苯乙烯是表征聚氯乙烯和聚苯乙烯之间排斥作用的Flory-Huggins参数。当Nχ聚氯乙烯/PSI较小时，发生微相分离，当Nχ聚氯乙烯/PSI较大时，发生大相或大相诱导的微相分离。用等边三角形相图讨论了相形成的途径，并绘制了均聚物/嵌段共聚物共混物的形态图。即使当均聚物的相对分子质量远大于可混相嵌段共聚物的相对分子质量，并且当均聚物是多分散的时候，也可以观察到微相的形成。事实上，由于当N较大时会形成大相，很明显，当存在高相对分子质量的均聚物时，低分子量嵌段共聚物是形成微相所必需的。
The formation of a microphase and a macrophase in solvent-cast homopolymer/block copolymer blends, where the homopolymer is exothermically miscible with one of the block copolymer segments, is demonstrated to depend on the molecular weights of the homopolymer and the incompatible segment of the block copolymer, in spite of the exothermic mixing. Binary blends of poly(vinyl chloride) (PVC) with poly(n-butyl-methacrylate-b-styrene) (PnBMA-b-PS) block copolymer, solvent cast from methyl ethyl ketone, were investigated. By varying the molecular weight, we vary the thermodynamic product NχPVC/PSwhich controls the phase morphology. Here N = NPVCNPS/NPVC1 2+ NPS1 2)2, where NPVCand NPSare the degrees of polymerization of PVC and PS block copolymer segment, respectively, and χPVC/PSis the Flory—Huggins parameter which characterizes the repulsive interaction between PVC and PS. Microphase separation is observed when NχPVC/PSis small; and when NχPVC/PSis large, macrophase or macrophase-induced microphase separation occurs. The routes of phase formation are discussed using equilateral triangular phase diagrams, and a morphology diagram is constructed for homopolymer/block copolymer blends. Microphase formation is observed even when the molecular weight of the homopolymer is much larger than that of the miscible block copolymer segment, and when the homopolymer is polydisperse. Indeed, since macrophase formation occurs when N is large, it is clear that low molecular weight block copolymer is necessary to form the microphase when a homopolymer of high molecular weight is present.
黄濑秀夫：Makromol Chem。
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