Isotactic polyvinyl alcohol (isot-PVA) derived from isotactic polyvinyl ether and syndiotactic polyvinyl alcohol (synd-PVA) derived from polyvinyl trifluoroacetate were acetalized with acetaldehyde. Isot-PVA showed a larger reactivity than synd-PVA, however synd-PVA and PVA's derived from polyvinyl acetate prepared by radical polymerization under various conditions showed nearly the same reactivity to each other. The reactivities of isot-PVA with boric acid and borax were also larger than those of the other PVA's. From these results and the previously reported one for the saponification of polyvinyl acetate samples, PVA's derived from polyvinyl esters prepared by radical polymerization seem to have similar steric structures. Short branches in the polymer molecule may be the chief reason for the difference of the crystallinity of these PVA samples.

View full abstract

The solution polymerization of tetrahydrofurfuryl methacrylate (TMA) in benzene was carried out at 40°C with azobisisobutyronitrile (AIBN) as an initiator. The rates (v_p) of polymerization were expressed by the following equation. v_p=1.45×10^-4×(AIBN) ^0.5×(TMA). The chain transfer constants for monomer and solvent were ca. 6×10^-5 and 1×10^-5 respectively. The polymer was changed to be insoluble by heating in air at 150°C or by treating with BF₃-etherate and epichlorohydrine.

View full abstract

The changes of the surface tensions to concentration of aqueous solution of polyvinyl alcohol (PVA) were measured by the drop method. The falls of the surface tensions with perfectly saponified polyvinyl acetate (PVAc) were negligible, and with partially acetylated PVA small. With partially saponified PVAc, the falls of the surface tensions became larger as increasing the residual acetyl contents and with the polymer having maldistributed residual acetyl groups the falls of the surface tensions were great. It is concluded that partially saponified PVAc having hydrophobic ester groups and hydrophilic hydroxyl groups maldistributed in a chain indicates the properties of polymer surface active agents.

View full abstract

It was previously reported that partially saponified polyvinyl acetate (PVAc) which had hydrophobic ester groups and hydrophilic hydroxyl groups maldistributed in a polymer chain indicated the properties of polymer surface active agents. The present investigation was undertaken to make clear the effects of polyvinyl alcohol (PVA) on the solubilization of oil soluble colour, Yellow OB and on gold colloid.
With both perfectly saponified PVAc and partially acetylated PVA, the solubilization of Yellow OB were low. With partially saponified PVAc, the solubilization of Yellow OB became higher as the residual acetyl contents were increased and the residual acetyl groups were maldistributed in a polymer chain.
Perfectly saponified PVAc indicated large gold number and the higher the degree of polymerization, the smaller the gold number. Partially acetylated PVA was almost same as perfectly saponified PVAc. Partially saponified PVAc had the excellent protective effects than other PVAs and the more its residual acetyl contents and maldistribution of residual acetyl groups in a polymer, the smaller the gold number.

View full abstract

For the purpose of finding the relationship between shifts of some absorption bands and the sequence lengths of styrene (St) units, several kinds of St copolymer were prepared by a radical catalyst, and their IR-spectra were measured.
Concerning St-methylmethacrylate (MMA) copolymer, it was found that the bands, 1068cm^-1 and 543cm^-1, shifted to 1075cm^-1 and 557cm^-1, respectively. As well-known, both bands, 1068cm^-1 and 543cm^-1, are assigned to a skeletal vibration coupled with CH deformation vibration of the phenyl group in polystyrene, so that the shift was considered to be due to the shortening of sequence length of St in the copolymer.
In the cases of such copolymers as St-ethylmethacrylate (EMA), St-methyl acrylate and Stmethyl vinyl ketone, the shifts of 543cm^-1 band to higher wave number side were also observed. In St-MMA copolymer, the absorption bands at 1148cm^-1 and 1191cm^-1 which are assigned mainly to MMA skeletal mode, shifted when the sequence length of MMA in the copolymer became short less than 3. Similar phenomenon was also observed in St-EMA copolymer.
Absorption band at 1062cm^-1 which is assigend to syndiotactic configuration of MMA disappeared in the course of copolymerization.

View full abstract

In order to confirm whether the sample (S-15) produced by a copolymerization reaction between styrene and propylene with Natta catalyst is a copolymer or not, solubility test and IR measurement were performed.
From the solubility test, it was found that most parts of the S-15 showed a different behaviour from that of a mixture of polypropylene and atactic polystyrene.
Furthermore, it was also found from IR measurement that two absorption bands at 1068cm^-1 and 543cm^-1 shifted to higher wave number side, except for the fraction extracted with ether. This shift did not occur in the case of blended polymers. Since these two bands are due to an intramolecular interaction between deformation vibration owing to a phenol group and skeletal vibration, the shift is considered to be due to a short sequence length of styrene in the copolymer.
From the results mentioned above, the S-15 was confirmed to be a copolymer.

View full abstract

The reactivities of initiator were studied from the dependence of graft efficiencies on the type of initiator. Graft copolymerization was performed at 60, 70, and 80°C in the cases of four systems: Polymethylmethacrylate-, poly (p-chlorostyrene)-, polystyrene- and poly (ethyl a-chloroacrylate)-2-methyl-5-vinylpyridine. In each case the homopolymers were separated from the graft copolymers by extraction. The different initiators used were benzoyl peroxide (BPO), lauroyl peroxide (LPO) and azobisisobutyronitrile (AIBN).
Graft efficiencies were varied with the different initiators and decreased slightly with increasing temperature of polymerization. The order of efficiencies was in order of LPO>BPO>AIBN. The differences in efficiencies could be explained by the primary radical attack to the trunk polymers, which depends on the nature of the initiator.
It was concluded that the primary radicals of LPO are less stabilized in resonance than that of AIBN.

View full abstract