摘要:

AbstractDTA combined with infrared analysis of the evolved gas (EGA) has been used to study the temperature behaviour, both in air and nitrogen, of commercial phosphorus‐ and nitrogen‐ and/or bromine‐containing flame retardants applied to cotton. By reference to the DTA traces and also the maxima occurring in the CO, CO2and H2O evolution rates, seven significant peak temperatures were assigned. Two new relatively low temperature peaks have been observed: the higher of these is DTA‐sensitive and occurs in all unretarded and retarded samples and is ascribed to the formation of an ‘activated cellulose’ state previously proposed by Bradbury, Sakai and Shafizadeh;17the lower peak is an exotherm (188‐220°C) associated with H2O and CO2evolution from flame‐retarded samples only. These observations are interpreted in terms of the mechanism of the cellulose pyrolysis/combustion and the influence of the

ISSN:0007-1641    

DOI:10.1002/pi.4980200112

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThermogravimetry, differential scanning calorimetry and curing studies were used to assess the viability of random and block copolymers comprising 1,4‐phenylene sulphide and 2‐methyl‐1,4‐phenylene sulphide repeat units as alternatives to poly(1,4‐phenylene sulphide) (PPS). The properties of the copolymers are discussed critically and compared with those of the parent homopolymers PPS and poly(2‐methyl‐1,4‐phenylene sulphide) (PMPS). The results suggest that (a) random copolymers with low PMPS contents would offer the best compromise between PPS and PMPS properties, and (b) more desirable physical properties might be achieved from systems containing a less reactive 2‐substituted‐1,4‐phenylene sulphide

ISSN:0007-1641    

DOI:10.1002/pi.4980200113

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractDifferential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) have been used in conjunction with tensile testing and transmission electron microscopy (TEM) to characterise novel segmented poly(urethane‐urea) (PUU) network materials formed by reaction injection moulding (RIM).Materials were based on a modified liquid 4,4′‐diphenylmethane diisocyanate and a polyether triol in admixture with one of three hindered aromatic diamines: 3,5‐diethyltoluene diamine (DETDA); methylene‐bis‐2,6‐diisopropylaniline (MMIPA); methylene‐bis‐(2‐methyl‐6‐isopropylaniline) (MMIPA).The materials ranged from tough translucent elastomers to opaque brittle plastics depending on the chemical nature and weight fraction of the hard segments (HS). DSC and DMTA studies showed the PUU materials to be phase‐separated; this was confirmed by TEM and tensile testing. The soft‐segment glass transition temperatures (DSC and DMTA) were independent of composition but varied with diamine structure. Hard‐segment glass transition temperatures could only be evaluated by DMTA and no evidence of crystallinity was found by thermal methods or by wide angle x‐ray diffraction. Heat capacity measurements and DMTA suggested that some degree of phase mixing had occurred, to a greater extent in the DETDA and MDIPA systems.Phase inversion was observed by DMTA and confirmed at ∼55% hard‐segment content f

ISSN:0007-1641    

DOI:10.1002/pi.4980200114

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0007-1641    

DOI:10.1002/pi.4980200117

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0007-1641    

DOI:10.1002/pi.4980200119

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0007-1641    

DOI:10.1002/pi.4980200121

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0007-1641    

DOI:10.1002/pi.4980200124

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0007-1641    

DOI:10.1002/pi.4980200125

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0007-1641    

DOI:10.1002/pi.4980200101

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY