摘要:

New polyesters formed by interfacial polycondensation of 2,5-bis(4-hydrox-ybenzylidene)cyclopentanone (I) and 2,5-bis(4-hydroxy-3-methoxybenzyli-dene)cyclopentanone (II) with 4,47prime;-diphenic, isophthaloyl, terephthaloyl, adi-poyl, suberoyl, and sebacoyl dichlorides were obtained. The yield and the values of the reduced viscosity of the produced polyesters were found to be affected by the type of organic phase, the quantitative ratio of organic to aqueous phase, the concentration of the hydrogen chloride acceptor, and the contribution of benzyltriethylammonium chloride as a catalyst. In order to characterize these polymers, the necessary model compounds were prepared from I, II, and benzoyl chloride. The resulting polyesters were confirmed by IR, elemental analysis, viscometry, DTA, DSC measurements, and thermogravi-metric analysis. The crystallinities of all polyesters were examined by x-ray analysis, and the electrical properties of the polyesters were tested.

ISSN:0022-233X    

DOI:10.1080/00222339009349640

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Synthesis and absorbency studies of a series of terpolymers of acrylamide (AM) with sodium 3-acrylamido-3-methylbutanoate (NaAMB) and 2-acryl-amido-2-methylpropanedimethylammonium chloride (AMPDAC) are reported. Terpolymers were synthesized with varying molar feed ratios of the three monomers; those containing greater than 1% charged groups were not water soluble but formed hydrogels. Ampholytic terpolymers synthesized from monomer mixtures of 5% AMPDAC, 10% NaAMB, and 85% AM exhibit a 230-fold weight gain in pure water and a 30-fold gain in 0.514MNaCl. Enhanced water absorbency of terpolymers with a charge imbalance is consistent with operative osmotic forces in crosslinked polyelectrolytes. The good absorbency in NaCl solutions can be attributed to hydration of paired cationic and anionic mer units in this terpolymer series.

ISSN:0022-233X    

DOI:10.1080/00222339009349641

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Based on the stability theory of continuous thermodynamics for polymer solutions, necessary and sufficient conditions for multiple critical points are derived assuming the segment-molar excess Gibbs free energy to be independent of the distribution function. Equations for calculating double and triple critical points are given. Higher order critical points may be obtained in a successive way. For polymers possessing a Schulz-Flory molecular weight distribution, general conditions for anm-fold critical point are presented.

ISSN:0022-233X    

DOI:10.1080/00222339009349642

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

It is shown that the Flory-Huggins X12parameter for a polymer, 1, with a solvent, 2, is proportional to the interfacial tension, Y12, between the polymer and the solvent. In the case of polyethylene glycol (PEG) dissolved in water, the value of Y12is strongly negative. It is shown that this condition gives rise to a sizable negative value of X12. which in turn engenders a strongly positive second virial coefficient of the osmotic pressure (II) function. X12values calculated for the PEG-water system from surface tension data of PEG and of water allow the calculation of II for aqueous solutions of PEG of up to 60% (w/v) for PEG of molecular weights of 150,400,6000, and 20 000. The results show an excellent correlation with the II values earlier measured for these polymers by Arnold et al. and furnish an explanation for the unusual lack of dependence of II on the polymer molecular weight and for the very high osmotic pressures observed with aqueous PEG and dextran solutions.

ISSN:0022-233X    

DOI:10.1080/00222339009349643

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The radical homopolymerization of 5-nitrofurfuryl methacrylate (NFMA) and the copolymerization of NFMA with methyl methacrylate and various vinyl monomers, respectively, have been studied in dimethylformamide at 65°C. NFMA and poly(NFMA) have been characterized by1H-NMR, IR, and UV spectroscopy. The influence of polymerization conditions on monomer conversion and on the molecular weight of the polymers obtained has been investigated. The thermal behavior of the polymers obtained has been studied by TGA and DSC analysis.

ISSN:0022-233X    

DOI:10.1080/00222339009349644

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Water-soluble sulfopropylcellulose (SPC) was synthesized by the reaction of 1,3-propane sultone with sodium cellulose in dioxane. The degree of substitution (0.3-1.0) was calculated by elemental analysis. The corresponding water-soluble polyacrylamide graft copolymer was prepared by Ce4+ion-initiated graft copolymerization of acrylmide onto sulfopropylcellulose dissolved in dilute nitric acid solution at room temperature under argon. The graft copolymerization was carried out in 0.2MNaNO3solution in order to suppress the ionic interaction between the sulfonate ion and eerie ion. The average number of grafts per SPC was found to be 1.1 or less, depending on the reaction conditions.

ISSN:0022-233X    

DOI:10.1080/00222339009349645

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Optically active mono-l-menthyl itaconate (MMI) was prepared from ita-conic acid and l-menthol. MMI was polymerized in bulk at 80°C to give a chiral homopolymer having -49.5° specific rotation. MMI (M1was copolymerized with styrene (ST, M2), methyl methacrylate (MMA, M2), and N-cyclohexylmaleimide (CHMI, M2) by using 2,2′-azobisisobutyronitrile (AIBN) as the radical initiator and benzene as the polymerization solvent at 50°C. The monomer reactivity ratios (r1, r2) and Alfrey-PriceQ, evalues were determined to be r1= 0.28, r2= 0.32, Q1= 0.90, and e1= 0.75 in MMI-ST; r1= 0.09 and r2= 0.51 in MMI-MMA; and r1= 0.78 and r2= 0.39 in MMI-CHMI. The chiroptical properties of the polymers were investigated.

ISSN:0022-233X    

DOI:10.1080/00222339009349646

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

A polymer carrier containing (β-diketone groups was synthesized by a free radical polymerization of methacrylacetone monomer and combined with titanium tetrachloride or stannic chloride in chloroform to form two very stable complexes containing 19.5 and 18.3% CI which are equivalent to 1.40 mmol TiCl4complex beads and 1.28 mmol SnCl4; complex beads, respectively. The two complexes showed good catalytic activity in many organic reactions such as acetalation, ketal formation, and esterification. The catalysts can be reused at least 8 times without losing their activity in organic reactions.

ISSN:0022-233X    

DOI:10.1080/00222339009349647

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

This paper deals with the homopolymerization of the systems styrene-azobisisobutyronitrile-dibutyl phthalate-50°C and styrene-benzoin-dibutyl phthalate-50°C. The dependencies of initiation and overall rates of the polymerization on the concentrations of monomer and the viscous solvent were studied. The absolute rate constants for chain propagation and termination were determined. The termination rate constant of the styrene-dibutyl phthalate system was found to be inversely proportional to the viscosity of the medium. The propagation rate constant was found to decrease with monomer concentration, which could be evaluated quantitatively in terms of the hot radical theory.

ISSN:0022-233X    

DOI:10.1080/00222339009349648

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor