摘要:

The Maron theory has been used to deduce from available thermal and other data expressions for the heats of solution and dilution of polystyrene in nine solvents. Also, a direct method is described by means of which the energy of the glass can be determined from heat of solution measurements. Applied to solutions of polystyrene in toluene, ethyl benzene, and chlorobenzene, this method gives for the energy frozen in the glass 8.02 0.19 cal/g of sample for a polymer of M2 = 150,000. This value compares reasonably well with the value of 7.07 cal/g obtained by Bianchi for a polymer of M2 = 250,000.

ISSN:0022-2348    

DOI:10.1080/00222346808212468

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

It has long been known that there are relationships between glass temperatures and melting points in semicrystalline polymers. Boyer [1] and Beaman [2] observed that the glass temperature is usually ½ to ⅔ of the melting point in degrees absolute. More recently, Boyer [3] has reviewed what is known about the dependence of these properties on molecular structure.

ISSN:0022-2348    

DOI:10.1080/00222346808212469

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

Recently, investigators of the melt flow properties of crystallizable polymers have observed transitions in the rheological behavior of the melt. [1, 2] These transitions have been attributed to changes in the ordering of the polymer molecules. In the study of the melt rheological properties of polypropylene, we have observed a similar behavior. This communication reports our initial findings.

ISSN:0022-2348    

DOI:10.1080/00222346808212470

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor