Terutake Homma

Crystallization and gelation of poly(vinylidene fluoride) in organic solvents

Poly(vinylidene fluoride) (PVdF) converts easily to thermally reversible gel at room temperature in aliphatic ketones or cyclic ketones such as 3-pentanone, 3-hexanone, cyclohexanone, and -butyrolactone, etc. Gelation of PVdF in these ketones took place through crystallization of polymers from solution. The crystallization process was investigated in detail by Fourier transform infrared (FTIR) measurements. The FTIR spectra were recorded continuously at room temperature until the solution converted to gel. It was suggested from spectral data that polymer chains packed together (i.e., crystallization took place) into the TTTGTTTG¯ conformation in the case of PVdF/γ-butyrolactone solution, followed immediately by gelation. On the other hand, crystallization occurred into the TGTG¯ conformation in the case of other ketones and gelation immediately took place. Melting temperatures of PVdF gels thus prepared from these solvents were measured. showed a solvent dependence.

INVERSE GAS CHROMATOGRAPHIC STUDY OF RUBBERS

いくつかの溶媒(プローブ)とゴム(EPRとNBR)との間の相互作用を温度60-200°Cの範囲でインバースガスクロマトグラフィー(IGC)で研究した.ゴムは薄膜として担体(クロモソルブWAW DMCS 60-80 メッシュ)に均一に塗布した. その担体をステンレスカラム(直径×長さ=2.2×2000mm)に充てんした.ゴム/溶媒系のレテンションダイアグラム(R.D.)はlnV0gと1/wのプロットで1/w=0に外挿したときのlnV0gを用いて得た. それぞれのゴムのR.D.は測定温度全領域で直線であった. ゴム/プローブ間の相互作用係数(χ12)はこのV0gから求めた. ヘキサンに対するEPRのχ12は60, 100, 180°Cで0.22, 0.15, -0.22であった. また, NBRではそれぞれ1.31, 0.84, 0.65であった. これらからこの温度範囲ではEPRはNBRよりヘキサンに強い相互作用を示すことがわかった. 同様に分散成分のみのペンタン, デカンおよび四塩化炭素でも同じ傾向が認められた. ゴム自身がEPRより極性のあるNBRでは極性成分を有する溶媒でEPRより小さいχ12を示した. 部分モル吸着熱(〓Hs1)も同じ傾向を示した.