摘要:

AbstractCalorimetric studies on kinetics of photopolymerization reactions made previously have been limited by the structures of the calorimeters. This report suggests a thermal‐leak type of calorimeter for carrying out kinetic analysis of the photopolymerization reaction. The method was applied to the photopolymerization system consisting of lauryl acrylate and benzoin methyl ether. The results obtained illustrate the utility of this apparatu

ISSN:0360-6376    

DOI:10.1002/pol.1978.170160601

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractAnionic polymerization ofp‐diisopropenylbenene was found to be an equilibrium polymerization not only with respect to the monomer but also with respect to the pendent double bond. The polymerization was studied from kinetic as well as from the thermodynamic point of view, especially to ascertain the reactivity of the pendent double bond as compared with the double bond of monomeric analog. It was shown that the crosslinking rate constant of the pendent double bond is lower by about three to four orders than the propagation rate constant of the monomeric analog. The rate of cyclization was also very slow. From the equilibrium, the heat and entropy of polymerization of the monomer were determined as ΔHss= −5.8 kcal/mole and ΔSss= −18.0 cal/deg mole, respectively, and those of the pendent double bond as ΔHss= −6.3 kcal/mole and ΔSss= −27.8 cal/deg mole. When compared with the polymerization of α‐methylstyrene, the low thermodynamic polymerizability of the pendent double bond is attributed to the low heat of polymerization, which may arise from the large steric hindrance of neighboring groups. The effect is much smaller for the equilibrium than for the rate of polymer

ISSN:0360-6376    

DOI:10.1002/pol.1978.170160602

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractFerrocenylmethyl methacrylate (FMMA) has been polymerized by using LiAlH4–tetramethyl‐ethylenediamine initiation to form living polymers in high vacuum systems. The addition of methyl methacrylate or acrylonitrile to these living systems gave the block copolymers FMMA‐block MMA and FMMA‐block AN. The anions were not nucleophilic enough to initiate styrene polymerization. Therefore, living polystyrene was prepared (sodium naphthalide initiation in THF at −78°C) and upon FMMA addition, styrene‐block FMMA copolymers were formed. Extraction, precipitation, and gel‐permeation chromatography studies were performed to examine the purity of the bl

ISSN:0360-6376    

DOI:10.1002/pol.1978.170160603

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe thermal decomposition of poly(vinylidene chloride) was studied for samples prepared in the presence of oxygen. The products from both mass and aqueous suspension polymerizations show two modes of thermal decomposition. A rapid initial mode varies in rate and extent with the amount of oxygen present. A slower mode is unaffected by oxygen and in similar in rate to the polymer made in the absence of oxygen. The chief volatile products are phosgene and formaldehyde for the rapid decomposition and hydrogen chloride for the slow decomposition. The rapid decomposition is interpreted to be an unzipping reaction of a vinylidene chloride–oxygen alternating copolymer initiated by homolysis of a peroxide bond. The absence of significant amounts of hydrogen chloride during this stage of decomposition shows that none of the free radicals generated are capable of initiating a chain reaction that would unzip hydrogen chloride from the poly(vinylidene chloride) backbone. The presence of oxygen during the aqueous suspension polymerization correlates with the generation of hydrochloric acid in the aqueous phase. By analogy with the high temperature decomposition, the hydrochloric acid is believed to result primarily from the hydrolysis of phosgene produced by partial decomposition of the polyperoxide. Initiation of the decomposition is believed due to a reaction of the chain propagating radica

ISSN:0360-6376    

DOI:10.1002/pol.1978.170160604

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe direct thermal condensation of aromatic methyl esters with aromatic amines and hydrazides was studied. Using model compounds, it was learned thatN‐methylation of amines (both aromatic and aliphatic) and hydrazides is inherent at temperatures required for condensation polymerization. This side reaction prevents attainment of high molecular weight polyamides, polyhydrazides, or polyoxadiazoles from the corresponding difunctional aromatic monomers by heat alone. Reported catalysts for the condensation reaction do not prevent the side reactio

ISSN:0360-6376    

DOI:10.1002/pol.1978.170160605

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe glass transition temperatureTgof nylon 6 decreases monotonically toward a finite valueTglupon increase of the moisture content. The mechanism of this decrease entails the reversible replacement of intercaternary hydrogen bonds in the accessible regions of the polyamide. The limiting glass transition temperatureTglis approached when the moisture content approachesWl, which corresponds to the amount of water required for complete interaction with all accessible amide groups. Denoting withTg0the glass transition temperature of the dry polymer, the effect of water onTgis represented by the equation,Tg= (ΔTg)0exp{−[ln(ΔTg)0]W/τWl} +Tgl, where (ΔTg)0=Tg0−Tgl, and τ =W(Tgl+1)/Wl. This equation appears to be generally applicable to hydrophilic polymers, since correspondingly calculated data are also in very good agreement with experimental data for polymers such as nylon 66, poly(vinyl alcohol), and polyN‐vinylpyrrolidone. The effect of water of Young's modulusEof nylon 6 is represented by an analogous relationship, and the quantity In[(E−El)/(Tg−Tgl)] is a linear function of the mo

ISSN:0360-6376    

DOI:10.1002/pol.1978.170160606

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe water‐soluble monomers, 1‐methyl‐4‐vinylimidazole, 1‐methyl‐5‐vinylimidazole, 1‐ethyl‐5‐vinylimidazole, and 1‐propyl‐5‐vinylimidazole have been synthesized, polymerized, and copolymerized with 4(5)‐vinylimidazole. The copolymers were characterized by14C‐labeling, NMR, pKadetermination and viscosity measurements. The monomer reactivity ratios determined by14C counting arer1= 1.04;r2= 0.94 [M1= 4(5)‐vinylimidazole, M2= 1‐methyl‐4‐vinylimidazole] andr1= 1.01;r2= 0.86 [M1= 4(5)‐vinylimidazole,M2= 1‐methyl‐5‐vinylimidazole]. The esterolytic activity of the copolymers for the hydrolysis ofp‐nitrophenyl acetate (PNPA) at pH 7–8 in 28.5% ethanol–water was higher than that of the mixtures of homopolymers. At pH 5–6 the esterolytic activities of the copolymers and the mixtures were similar. The most efficient esterolytic activity for PNPA hydrolysis at pH 7.11 in 28.5% ethanol–water occurred for copolymers containing 75 mole % 4(5)‐vinylimidazole and for copolymers containing 1‐me

ISSN:0360-6376    

DOI:10.1002/pol.1978.170160607

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractWater‐soluble copolymers containing imidazole andN‐alkylated imidazole pendant groups have been synthesized in order to investigate the hydrophobic interactions between polymeric catalysts and long alkyl chain ester substrates. Copoly[1‐methyl‐4‐vinyl‐imidazole/4(5)‐vinylimidazole],copoly[1‐methyl‐5‐vinylimidazole/4(5)‐vinylimidazole], copoly[1‐ethyl‐5‐vinylimidazole/4‐(5)‐vinyl‐imidazole] and copoly[1‐propyl‐5‐vinylimidazole/4(5)‐vinylimidazole]were synthesized and their catalytic activity toward 3‐nitro‐4‐acyloxybenzoic acid substrates (Sn−) was determined in 28.5% ethanol–water and in water and compared with that of the mixtures of homopolymers. Hydrophobic interactions were important for rate enhancement of the hydrolysis of long‐chain ester substrates compared to that of short‐chain ester substrates. The copolymers catalyzed the hydrolysis of 3‐nitro‐4‐dodecanoyloxy‐benzoic acid (S12−) about two times faster than the mixtures at pH 7.11 in 28.5% ethanol–water. The hydrolysis of S12−by the cop

ISSN:0360-6376    

DOI:10.1002/pol.1978.170160608

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractModified polyethylenimines have been prepared containing imidazole and dimethylamine functionalities for catalytic purposes, as well as apolar groups to increase binding. The cooperative effect of the two functionalities increases the catalytic effectiveness of these polymers some 2–20‐fold, depending on the kinetic parameters being compa

ISSN:0360-6376    

DOI:10.1002/pol.1978.170160609

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractFive‐membered cyclic esters of phosphoric acid of the general formula: CH2CH(R)OP(O)‐(OR′)O polymerize readily to solid, soluble polymers of high molecular weight without any rearrangement known for various tri‐ and pentavalent organophosphorus monomers.1H‐,13C‐, and31P‐NMR spectra of polymers confirmed their linear structure:where R is H, with R′ = CH3, C2H5,n‐C3H7,i‐C3H7;n‐C4H9, CCl3CH2, or C6H5, or R is CH2Cl and R′ is C2H5. The use ofn‐C4H9Li, (C5H5)2Mg, or (i‐C4H9)3Al as initiators le

ISSN:0360-6376    

DOI:10.1002/pol.1978.170160610

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY