Dimethylamino-terminated poly (tetrahydrofuran) (AT-PT) was synthesized by the living cationic polymerization of tetrahydrofuran followed by the reaction with dimethylamine. AT-PT or the mixture of AT-PT and N, N, N′, N′-tetramethylpropane diamine was subjected to the reaction with α, α′-dichloro-p-xylene to produce poly (tetrahydrofuran) ionene (PTI). PTI was a highly elastic material, and soluble in polar water or mathanol and nonpolar chloroform. The viscosities in polar solvents showed the polyelectrolyte behavior, but in chloroform the behavior was that of non-polyelectrolyte. PTI film adsorbs both water and heptane vapors. The change of the counter anion influenced the water adsorption, but did not on that of heptane. Gas permeation through PTI film showed that water permeated much faster through PTI than the NR vulcanizate, and there was not much difference in N₂ and O₂ permeabilities between PTI and NR. All these results suggest that PTI is amphiphilic, that is, both hydrophilic and hydrophobic.

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Tensile properties of the elastomeric ionenes containig poly (tetrahydrofuran) segments (PTI) were investigated. PTI exhibited excellent tensile properties: modulus at 100% elogation, 0.5-2.0MPa; tensile strength, 20-30MPa; elongation, 600-1000%. However, the tensile properties became very low when the water content exceeded 30%. This lowering is due to the presence of ionic sites. The recovery of the original tensile properties suggests that the lowering by water is not ascribable to the chemical deteriorations, e.g., hydrolysis of PTI. Effects of the concentration of ionic sites and the kind of counter anions on tensile properties were also reported. The introduction of dianion, e.g., ^-O₃SCH₂CH₂SO^-₃ had a considerable effect to increase the modulus of PTI.

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If we can gain better understanding about the chain arrangement of component monomers in EPDM molecule, especially the long chain sequence of ethylene, it will add to the basic knowledge of the crystallinity of ethylene in EPDM that dictates the processability of EPDM raw rubber. For the purpose of this study, we have selected EPM, ethylene•butene-1 copolymer and ethylene•4-methylpentene-1 copolymer as model compounds which are prepared by using various Ziegler-type catalyst.
These model compounds were analyzed by ¹³C-NMR spectrometer to investigate the arrangement of ethylene in the copolymers. In this study, we have developed here a new concept of“block methylene average length (BMAL)”and studied its relationship to the crystallinity obtained by X-ray study and to the physical properties such as tensile strength of the raw rubber.
As the results, (1) The value of BMAL is found to be proportional to the degree of ethylene content, and it differs from the kind of used catalyst. (2) There are some relationships between crystallinity and BMAL for each copolymer. (3) The relationships between crystallinity and tensile strength of copolymers are also proportional. Additionaly, assignment of the ¹³C-NMR spectrum of the ethylene•4-methylpentene-1 copolymer has been reported.

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Polyurethane networks based on poly(oxypropylene) glycol (PPG, Mn=988) were prepared by incorporating hard segment oligomers. The hard segment oligomers were prepared by step synthesis. Trimers (BD-TDI-BD) were prepared by end-capping 2, 4-tolylene diisocyanate (TDI) with the large excess of 1, 4-butanediol (BD) and were purified by fractional precipitation. Heptamers (BD-(TDI-BD)₃) were prepared from the trimer and TDI. The polydispersity indices (Mw/Mn) of trimer and heptamer were 1.1 and 1.4, respectively. Polyurethane networks based on PPG-TDI-BD were isotropic rubbery materials when prepared by usual prepolymer method. The incorporation of the trimer also resulted in isotropic rubbery ones. However, the heptamer resulted in partially micro-phase separated structure. Morphology of these networks were studied by measuring DSC, WAXS, SEM, etc. Properties of the polyurethane networks changed by incorporating hard segment oligimers in the following ways. The effects were enhanced with increasing hard segment length; Chemical crosslinking density and polymer density increased. The glass transition temperature of soft domain lowered. The high temperature transition of hard domain rose. Modulus increased but tensile strength and elongation at break decreased.

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