摘要:

AbstractBicyclo[2.2.2]oct‐2‐ene has been polymerised by ring opening using a catalyst consisting of (mesitylene)W(CO)3/EtAlCl2/2,3‐epoxynorbornane/Me4Sn and a trace of norbornene. The polymer was characterised by13C n.m.r. and contained 32%cisdouble bonds, with a somewhat blockycis/transdouble bond distrib

ISSN:0007-1641    

DOI:10.1002/pi.4980170111

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractPolymerisations of 2‐vinylnaphthalene and 4‐vinylbiphenyl and copolymerisations of these monomers with methyl methacrylate have been initiated by azobis(isobutyronitrile) enriched in its methyl groups with carbon‐13. The environments of (CH3)2C(CN)‐ end‐groups in the copolymers have been examined by13C nuclear magnetic resonance. It has been concluded that both aromatic monomers are more than twice as reactive as methyl methacrylate towards the primar

ISSN:0007-1641    

DOI:10.1002/pi.4980170112

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractAlginate‐entrapped livingKluyveromyces marxianusNCYC179 cells were successfully used in alcohol production from whey permeate. Using 10% whey lactose as substrate, an alcohol production efficiency of 81.5–84.9% and 84.0–88.2% with cell viability maintenance between 82.8–84.3% and 81.0–84.3% of the immobilised cells during the monitoring periods, in batch (six repeat runs) and continuous (23 days of experimenting time) systems, respectively. The immobilised samples remained stable during the course of fermentation with no leakage ofK. marxianuscells into the surrounding medium in the case of the batch system. However, slight leakage after 10 days of continuous run in the continuous process was recorded. The scanning electron microscopic studies of the beads containing entrapped yeast cells and sections or crushed samples of the beads carried out at the start and termination of fermentation in both the processes (batch and continuous) revealed that the immobilisation procedure does not influence any morphological change in the entrapped cells during the prolonged periods of fermentation. Moreover, the gel matrix structure was also found to be unaffected by the fermentation conditions employed during the course of presen

ISSN:0007-1641    

DOI:10.1002/pi.4980170113

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractMethyl groups from chain scission and H‐crosslinks have been identified by solid‐state nuclear magnetic resonance in amorphous ethylene‐propylene copolymers containing 23 and 36 mole % propylene after γ‐irradiation to 10 MGy at 30°C.G(scission) andG(crosslink) values determined from the n.m.r. spectra and by extraction are in agreement, which suggests that the crosslinks are not clustered. This may differ from the situation in polyethylene where there is a substantial crystalline content.G(S).G(X) and the ratioG(S)/G(X) increase with increasing propylene content of the c

ISSN:0007-1641    

DOI:10.1002/pi.4980170114

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe immobilisation of α‐amylase (E.C.3.2.1.1) on Biozan R with dicyclohexyl carbodiimide as an activator has been studied. The reaction was proved to be influenced by the enzyme support and activator support ratios as well as by the reaction duration. The function correlating the coupled enzyme activity with process parameters was derived by processing the experimental results obtained by means of a second order, composite, centrate, rotatable experimental design, using the multiple regression method. The activity of the coupled enzyme was dependent on the temperature and pH of the incubation reaction. The Michaelis‐Menten constant is higher for the immobilised enzyme as compared with the free

ISSN:0007-1641    

DOI:10.1002/pi.4980170115

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe present paper reports the performance of a bioreactor packed with alginate‐entrappedKluyveromyces marxianusNCYC179 for continuous fermentation of whey permeate to ethanol. A maximum ethanol productivity as 28.21 gl−1h−1was attained atD=0.42h−1and 75% lactose consumption (substrate feed rate in the inflowing medium was 200 g lactose I−1). However, the higher dilution rates (0.6‐1.Oh−1) resulted in poor productivities and higher substrate washout in the effluent samples. The maximum specific ethanol production (qpi) and maximum specific lactose uptake (qsi) of the immobilisedKluyveromyces marxianusNCYC179 was found to be 3.88g ethanol/g immobilised cell/hx10−2and 8.75g lactose consumed/g immobilised cell/hx10−2respectively. A bead size of 2.5 mm in diameter and activation period of 24h of alginate beads in lactose solution (10%) prior to their packing in column reactor were found to support the efficient working of the bioreactor. The immobilised cell bioreactor system was operated continuously at a constant dilution rate of 0.15h−1and 10% lactose for 562 h without any significant change in the efficiency (varied from 84 to 88% of theoretical) and viability of the entrapped yeast cells (drop

ISSN:0007-1641    

DOI:10.1002/pi.4980170116

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractPolymerisation of phenolphthalein‐based epoxy resin with phthalic anhydride has been investigated by differential scanning calorimetry. The overall polymerisation kinetics were found to be independent of the concentration of phthalic anhydride and scan rate. The polymerisation was found to follow a simple Arrhenius‐type temperature dependence up to about 80% complet

ISSN:0007-1641    

DOI:10.1002/pi.4980170117

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe mechanical fracture strength and toughness of short‐fibre composites, injection moulded from compounds of poly(ethylene terephthalate) (PET) containing 10 and 30% (by weight) (w/o) glass, have been investigated and the dependence upon matrix hydrolytic stability determined. Mouldings have been characterised by several physical techniques to evaluate molecular weight, degradation rates, crystallinity and morphology, whilst time‐dependent gravimetric data were derived to quantify sorption kinetics and allow comparisons with theoretical reaction rates to be made. During melt processing, PET is hydrolysed extremely rapidly by traces of moisture (<0.02w/o). yet the inherent strength of moulded composites declines significantly only below an apparently critical molecular weight. However, on long‐term humid ageing in hot water, impact behaviour especially is rendered more complex by simultaneous crystallisation, molecular reorder and losses of interfacial bond str

ISSN:0007-1641    

DOI:10.1002/pi.4980170118

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractCopolyesters containing poly(ethylene terephthalate) and poly(hexamethylene terephthalate) (PHT) were prepared by a melt condensation reaction. The copolymers were characterised by infrared spectroscopy and intrinsic viscosity measurements. The density of the copolyesters decreased with increasing percentage of PHT segments in the backbone. Glass transition temperatures (Tg). melting points (Tm) and crystallisation temperatures (Tc) were determined by differential scanning calorimetry. An increase in the percentage of PHT resulted in decrease inTg,TmandTc. The as‐prepared copolyesters were crystalline in nature and no exotherm indicative of cold crystallisation was observed. The relative thermal stability of the polymers was evaluated by dynamic thermogravimetry in a nitrogen atmosphere. An increase in percentage of PHT resulted in a decrease in initial decomposition temperature. The rate of crystallisation of the copolymers was studied by small angle light scattering. An increase in percentage of PHT resulted in an increase in the rate of crystallisatio

ISSN:0007-1641    

DOI:10.1002/pi.4980170119

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0007-1641    

DOI:10.1002/pi.4980170122

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY