摘要:

AbstractQuantitative thermal analysis was carried out for poly‐(pivalolactone) (PPVL), including heat capacity determinations from 140 to 550 K. The experimentalCpbelow the glass transition temperature was fitted to an approximate vibrational spectrum and the ATHAS computation scheme was used to compute the “vibration only” heat capacities from 0.1 to 1000 K. The liquidCpwas derived from an empirical addition scheme and found to agree with the experimentalCpwith an RMS of ±2.8% from 240 K to 550 K. A glass transition,Tg, could be detected at 260 K, and the change in heat capacity for 100% amorphous PPVL was calculated to be 38.8 J/(K mol). AboveTg, semicrystalline samples seem to show a rigid amorphous fraction that does not contribute to the increase in heat capacity atTg. Using the ATHAS recommended heat capacities, the various thermodynamic functions (enthalpy, entropy, and Gibbs function) were derived. The residual entropy at 0 K for the amorphous PPVL was calculated to be 5.2 J/(K mol) per mobile bead, and was comparable to that obtained for a series of linear, aliphatic polyesters analyzed e

ISSN:1042-7147    

DOI:10.1002/pat.1992.220030202

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractAcid‐labile polymers of methacrylates of 2‐(p‐substituted phenyl)propanol‐2 and bis(p‐methoxyphenyl)methanol were evaluated as visible light sensitive positive‐type resists. The chemistry to form images is based on the cleavage of esters catalysed by an acid generated by photodecomposition of diphenyliodonium hexafluorophosphate sensitized by 2‐benzoyl‐3‐(p‐dimethylaminophenyl)‐2‐propenenitrile. A copolymer of bis(p‐methoxyphenyl)methyl methacrylate‐phenyl methacrylate exhibited a high photospeed upon exposure to 488 nm light when coupled with the iodonium salt and the dye, and was appl

ISSN:1042-7147    

DOI:10.1002/pat.1992.220030203

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractCopolymers of oligo(oxyethylene) methacrylates and a series of polar comonomers, i.e. acrylamide, acrylonitrile and maleic anhydride, were synthesized as media for dual‐ or single‐ion conduction, and correlation between polymer structure and properties was established through detailed studies on polymer morphology, mechanical property and the ion transport process. Polar groups in the polymer chain sequence were found to enhance matrix polarity and to retard oligoether crystallization, as well as to raise chain rigidity. Therefore, both novel dual‐ and single‐ion conduction are realized, with a simultaneous improvement in the mechanical properties of polymer materials. An investigation about the effect of matrix polarity on the ion transport process is also carried out, making use of the concepts concerning polymer segmental relaxation. Hence the enhanced matrix polarity is found to contribute to the improvement in ion conduction, mainly through its promotion of salt dissociation. However, at high temperature this facilitation is counteracted due to the “anomalous” temperature‐dependence of salt dissociation in the polymer matrix, and the higher the matrix polarity, the more drastic is the drop in carrier number with risin

ISSN:1042-7147    

DOI:10.1002/pat.1992.220030204

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractAn ethylene—propylene (EPR) copolymer functionalized with (1,2‐dicarboethoxy)ethyl groups has been blended with a vinylidene fluoride—hexafluropropene elastomer (NML). The existence of intermolecular interactions involving mainly the carbonyl groups of the side chains of the functionalized copolymer and the methylene hydrogens of the fluoroelastomer through hydrogen bonding was shown by means of FT—IR spectroscopy. The structure and composition of some microdomains in the mixture was examined by means of FT—IR microspe

ISSN:1042-7147    

DOI:10.1002/pat.1992.220030205

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractPhase transition of the layer structure of poly(p‐benzenedithiol‐co‐p‐diethylbenzene) obtained in solid state polymerization was studied by a thermal treatment or UV irradiation under a nitrogen atmosphere. The peak intensities in the X‐ray diffraction diagram of polymers gradually decreased with the thermal treatment time above 55°C. Below 50°C the layer structure of polymers hardly changed. The apparent activation energy for the phase transition was about 15 Kcal/mol [63 KJ/mol] at the initial stage and gradually decreased to a few Kcal/mol [ca. 2 KJ/mol]. UV light from a high‐pressure mercury lamp also gradually induced the phase transition from the layer structure to an amorphous one. The pristine polymer possesses phase transition points at 75, 95 and 130°C. The exothermic transition at 75°C can be understood as the thermal destruction of the semistable layer structure. The exothermic transition at 95°C may be correspond to the cis → trans thermal isomerization of the C°C bond in the polymer main chain.The diffuse reflectance spectrum of the pristine polymer differed from that of the amorphous polymer obtained by the thermal treatment of the pristine polymer. SEM photographs of the pristine polymer showed a particular surface structure, i.e. entangled fibrous material. TEM photographs of the pristine polymer exhibited a bright valley‐and‐hill structure, whereas that of the amorphous polymer obtained by thermal treatment

ISSN:1042-7147    

DOI:10.1002/pat.1992.220030206

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractThe thermal stability of polystyrene (PS) blends with polyvinyl acetate (PV Ac) has been investigated. It was found that PV Ac acts as a sensitizer of the thermal degradation of these blends when the process takes place in a nitrogen atmosphere. In air PV Ac acts as a stabilizer, and the temperature of the decomposition of these blends is higher than that of pure PS. This stabilization is caused by PV Ac favoring an oxidation reaction without breaking the polymer chains.

ISSN:1042-7147    

DOI:10.1002/pat.1992.220030207

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractThe reaction of monodispersed silica colloid with hydrophobic and hydrophilic polymer coupling agents in the presence of ammonia afforded dispersible polymer/SiO2composites into organic solvents without aggregation.

ISSN:1042-7147    

DOI:10.1002/pat.1992.220030208

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

ISSN:1042-7147    

DOI:10.1002/pat.1992.220030210

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

ISSN:1042-7147    

DOI:10.1002/pat.1992.220030211

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

ISSN:1042-7147    

DOI:10.1002/pat.1992.220030201

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY