Polymer Journal

Lian, Yanqing; Li, Mingqi; Zhan, Jun; Zhou, Qixiang; Liu, Deshan

doi: 10.1295/polymj.31.1189pmid: N/A

Mesogenic diol monomer, terephthaloyl dioxydibenzoic acid diol ester (n=2, 3, 4, 5, 6), were prepared from ω-hydroxyalkyl-4-hydroxybenzoate and terephthalyl chloride, using Schotten–Baumann Reaction. New liquid crystalline polyurethanes (LCPUs) were obtained by solution polymerization mesogenic diol monomers with 4,4′-diphenylmethane diisocyanate (MDI) and 2,4-tolylene diisocyanate (2,4-TDI). The monomer and polyurethanes were investigated by DSC, polarizing microscopy, wide-angle X-ray diffraction (WAXD), small-angle X-ray diffraction (SAXD) and high temperature X-ray diffraction. All LCPUs Synthesized showed a nematic LC nature with wide temperature range.

Djoković, Vladimir; Kostoski, Dušan; Dramićanin, Miroslav D; Suljovrujić, Edin

doi: 10.1295/polymj.31.1194pmid: N/A

The stress relaxation of unoriented (λ=1) and oriented (λ=9) high density polyethylene (HDPE) was studied for different levels of radiation (0, 100, 300, and 500 kGy). The relaxation behavior is analyzed in terms of a formerly established two-process model. In that model, one process is related to the crystal and the other to the amorphous fraction of a polyethylene sample. The modified viscoelastic properties of HDPE, due to effects of orientation and irradiation, are reflected in changes in viscosity coefficients and elasticity moduli of these two fractions. This made possible better comprehension of the nature of changes in the relaxation behavior of HDPE induced by irradiation and orientation.

Shin, Dong Cheon; Chang, Youngkyu; Kim, Jin Seok; Noh, Icksam; Kim, Chulhee; Song, Kigook

doi: 10.1295/polymj.31.1200pmid: N/A

A new type of thermally stable second-order nonlinear optical (NLO) polycyanurate was synthesized by coupling Disperse Red 1 to the aryl hydroxyl-containing linear polycyanurate, which was prepared by the interfacial polymerization of 2-(4-(2-tetrahydropyranyloxy)phenyl)-4,6-dichloro-1,3,5-s-triazine with bisphenol A and by subsequent deprotection of tetrahydropyranyl groups. The new NLO polycyanurate exhibited a glass transition at 167°C and an initial thermal decomposition at about 300°C. The electro-optic coefficients of NLO polycyanurate poled at 1 MV cm−1 were 19 pm V−1 at 633 nm, 13 pm V−1 at 830 nm, and 6 pm V−1 at 1.3 μm. The stability of NLO activity was demonstrated at elevated temperatures.

Chang, Chi-Chin; Chen, Kun-San; Yu, T Leon; Chen, Yung-Sin; Tsai, Chin-Lung; Tseng, Yu-Hsien

doi: 10.1295/polymj.31.1205pmid: N/A

Polyester based polyurethanes were synthesized from 4,4′-methylene bis(phenyl isocyanate) (MDI) with 1,4-butanediol as a chain extender and low molecular weight polyester-diol as a soft segment. Four polyesters were used in the synthesis of polyurethanes. Two of the polyesters were synthesized from monomers with even carbon atoms, i.e., adipic acid with 1,6-hexanediol (polyester-6-6) and adipic acid with 1,4-butanediol (polyester-6-4). The other two polyesters were synthesized from monomers with odd carbon atoms, i.e., pimelic acid with 1,5-pentanediol (polyester-7-5) and 1,5-pentanedioic acid with 1,5-pentanediol (polyester-5-5). The effects of compatibility between soft- and hard-segments and the chemical structures of polyesters on the phase segregation of soft- and hard-segments were studied by DSC and FT-IR.

Banda, Lameck; TranCong-Miyata, Qui; Nomura, Shunji

doi: 10.1295/polymj.31.1211pmid: N/A

The onset of a segregation process in segmented polyurethaneurea (SPUU) solutions was studied by fluorescence spectroscopy using free fluorescein as a probe. For SPUUs with a given molecular weight and a constant ratio of the hard to soft segments, the time-resolved fluorescence measurements reveal the environmental inhomogeneity on the excited lifetime of fluorescein. It is shown in this work that the critical concentration for the segregation process detected by fluorescence spectroscopy through the transition of the anisotropy ratio of the fluorescein occurs at a concentration lower than that observed by small angle X-ray scattering (SAXS). These experimental results indicate that fluorescence depolarization can be used as an alternative method to investigate the structural transition in SPUU solutions.

Nishioka, Noboru; Itoh, Takeshi; Uno, Masakuni

doi: 10.1295/polymj.31.1218pmid: N/A

Homogeneous grafting of 2-hydroxyethyl methacrylate onto cellulose was carried out in a dimethyl sulfoxide/paraformaldehyde solvent system. The grafted products were added to cellulose/poly(2-hydroxyethyl methacrylate) (PHEMA) blends as compatibilizers. The thermal decomposition behavior of the blends was investigated by thermogravimetry. The thermal stability of the blends decreased with an increase in grafted product content. Peak intensity of wide-angle X-ray diffraction patterns decreased with grafted product content. The microphase-separated structures of the blends became finer with grafted product content. Dynamic mechanical measurements were carried out to determine glass transition temperatures, T g, of the blends. T g for cellulose decreased with grafted product content but that for PHEMA increased. Differences in thermal decomposition behavior of the blends were correlated to compatibility. Thermogravimetry was effective for compatibility estimation in cellulose/PHEMA blends containing grafted products.

Brar, Ajaib Singh; Thiyagarajan, Muthiah

doi: 10.1295/polymj.31.1224pmid: N/A

trans-4-Acryloyloxyazobenzene/vinylidene chloride (A/V) copolymers of different monomer concentrations were prepared by solution polymerization using benzoyl peroxide as initiator. The copolymer composition was determined from the quantitative 13C{1H} NMR spectrum. The carbonyl carbon of A- and the quaternary carbon of V-centered resonances were used for determining the sequences in terms of the distribution of A- and V-centered triads. The sequence distribution of A- and V-centered triads determined from 13C{1H} NMR spectrum of the copolymer is in good agreement with triad concentration calculated from statistical model. The comonomer reactivity ratios, determined by both Kelen–Tüdos (KT) and nonlinear error in variables (EVM) method are r A=0.36±0.03, r V=1.02±0.06; r A=0.37 and r V=1.04, respectively. 13C Distortionless enhancement by polarization transfer (DEPT) spectrum was used to differentiate the resonance signals of methine (A) and methylene carbon signals of A- and V-units. Assignments to the methine and methylene resonance signals have been assigned up to the tetrad levels using 2D HSQC experiments. The geminal coupling in the methylene and methine proton region is shown in the 2D TOCSY spectrum.

Ishihara, Kazuhiko; Iwasaki, Yasuhiko; Nakabayashi, Nobuo

doi: 10.1295/polymj.31.1231pmid: N/A

As water-soluble amphiphilic polymers with the phospholipid polar group (PMB), 2-methacryloyloxyethyl phosphorylcholine(MPC) copolymerized with n-butyl methacrylate (BMA), were synthesized. The properties of the MPC polymers in water were investigated by surface tension measurement, 1H NMR and fluorescence spectroscopy, and light scattering measurement. The solubility of the MPC polymers in water depended on MPC unit composition and molecular weight. The surface tension of the aqueous solution depended on the MPC unit composition in the PMB. In the case of poly(MPC), the surface tension did not change as in the case of water at polymer concentrations from 10−5 gd L−1 to 10−1 gd L−1. However, introduction of the BMA unit in the MPC polymer induced decrease in surface tension considerably above 10−4 g dL−1 polymer concentration. This result clearly shows that the PMB forms aggregates in water. According to fluorescence spectroscopy results, the PMB aggregate formed a hydrophobic domain in water and the polarity of the hydrophobic domain was the same as that of n-butanol. From the NMR spectra of the PMB in D2O at various temperatures, the phosphorylcholine groups were located at the surface of aggregate below 60°C. The light scattering measurement revealed that the size of the PMB aggregate in water was 23 nm. A hydrophobic fluorescence probe was entrapped in the hydrophobic inside of the PMB aggregate. The PMB aggregate thus quite likely has potential application as a novel drug carrier, to maintain hydrophobic drugs inside polymer aggregates stably.

Yamazaki, Shinichi; Yoshida, Takahiro; Muroga, Yoshio; Noda, Ichiro

doi: 10.1295/polymj.31.1237pmid: N/A

Potentiometric titration of aliphatic α,ω-diamines such as 1,3-, 1,4-, and 1,6-diamines was carried out in aqueous solutions with and without added salt to study the effect of electrostatic interactions on the chain conformations. The ratios of first to second association constants of proton K 1/K 2 Were larger than 4 indicating the effects of electrostatic interactions on the second association constant in a similar manner as α,ω-diacids. These data were analyzed by the theories of Bjerrum and Kirkwood–Westheimer, and the resulting charge distances were compared with the end-to-end distances of various chain models.

Ge, Xuewu; Sheng, Minya; Ye, Qiang; Xu, Xiangling; Zhang, Zhicheng

doi: 10.1295/polymj.31.1243pmid: N/A

A new terpolymer of acrylamide with sodium acrylate and (2-methacryloyloxyethyl)trimethylammonium chloride initiated with 60Co γ-ray was prepared in inverse emulsion. Polymerization conversion was studied dilatometrically and molecular weight was determined viscometrically. The effects of dose rate, monomer concentration, emulsifier content, temperature, etc. on the polymerization rate or conversion and the molecular weight of polymer were examined. The rate of polymerization (Rp) can be represented by Rp∝D 1.03[M]0.69[E]−0.02. The overall activation energy for the rate of polymerization is 12.90 kJ mol−1 (33—56°C). Based on these experimental results, aspects of the polymerization mechanisms are discussed.