摘要:

AbstractAn exploratory investigation has been carried out into a segmented polyether ester which consists of amorphous soft segments of polytertramethylene ether glycol and crystalline short chain hard segments of polyethylene terephthalate. The properties of this block copolymer have been compared with those of polyethylene terephthalate and polytetramethylene terephthalate (PTMT) and with those of the block copolymer based on PTMT. After a description of the preparation and the structure of the polyether ester, the thermal properties are discussed by means of DTA thermograms. From the stress‐strain behaviour, compared with that of the homopolymers, the elastomeric properties of the block copolymers stand out clearly. Processing characteristics are discussed on the basis of the crystallisation behaviour and the relationship between melt viscosity and shear rate. Finally, data about u.v., oxidative and hydrolytic stability are give

ISSN:0007-1641    

DOI:10.1002/pi.4980070402

出版商:John Wiley&Sons, Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe temperature dependences of some selected infrared bands of poly(vinylchloride) in the vicinity of the glass transition were examined. The intensities of 1333 and 1427 cm−1bands changed discontinuouly atTg; on the other hand, 2920 cm−1did not show any significant changes at this temperature. From these results, the nature of the temperature dependence of infrared intensity of the polymer was discussed. The procedure introduced in this work offers a rapid method for the determination of theTgas compared with the conventional infrared meth

ISSN:0007-1641    

DOI:10.1002/pi.4980070403

出版商:John Wiley&Sons, Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractA model polyurethane elastomers system has been used to study the relationships between chemical formulation, polymer physical structure and mechanical properties. The elastomers were made from formulations comprising a polyether polyol blend (diol plus triol), a chain extender blend (1,4 butane diol plus 1,1,1‐trimethylol propane) and 4,4′‐di‐isocyanate diphenylmethane. The morphologies of the elastomers were investigated in detail, mainly by means of small angle X‐ray scattering techniques. It was confirmed that the polyurethane systems examined comprised domains 50 to 100 Å in size and spaced around 100 to 200 Å apart. A complete decription of the polyurethane morphology has been made in terms of the volume fraction of domains present, the average domain size and the average domain–domain separation. The results suggest that, whilst it is possible to correlate, in general, formulation changes with variations in the elastomer morphology, it seems that direct correlations between physical structure and mechanical properties are not very meaningful in the present model system. However, it is clear that knowledge of the morphology is of considerable importance in interpreting the effects of formulation on observ

ISSN:0007-1641    

DOI:10.1002/pi.4980070404

出版商:John Wiley&Sons, Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe surface properties of silicones are responsible for many of their varied applications. An explanation in basic terms is given in this paper for this surface activity together with some insight into several of the applications that result from this surface activity.

ISSN:0007-1641    

DOI:10.1002/pi.4980070405

出版商:John Wiley&Sons, Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe pyrolytic and catalytic dehydrobromination of 2‐bromoethyl bromobenzene was studied as a step in the production of bromostyrene. The studies were carried out in a micropulse reactor attached to a gas chromatograph and in a number of ordinary flow reactors. Most of the work was carried out on 2‐Cl and 2‐Br ethyl benzene as model compounds. Catalytic effects of metals, oxides and molten salts were found. The pyrolytic reaction in the micropulse and flow reactors proved to be much faster than expected from the literature data on the monomolecular elimination studied in static systems. The addition of peroxides accelerates the reaction further and results in high conversions and high purity monomers at relatively low tempera

ISSN:0007-1641    

DOI:10.1002/pi.4980070406

出版商:John Wiley&Sons, Ltd    

年代:1975

数据来源: WILEY

ISSN:0007-1641    

DOI:10.1002/pi.4980070407

出版商:John Wiley&Sons, Ltd    

年代:1975

数据来源: WILEY

ISSN:0007-1641    

DOI:10.1002/pi.4980070408

出版商:John Wiley&Sons, Ltd    

年代:1975

数据来源: WILEY

ISSN:0007-1641    

DOI:10.1002/pi.4980070409

出版商:John Wiley&Sons, Ltd    

年代:1975

数据来源: WILEY

ISSN:0007-1641    

DOI:10.1002/pi.4980070401

出版商:John Wiley&Sons, Ltd    

年代:1975

数据来源: WILEY