A new free volume distribution function for amorphous polymers is derived on the basis of a lattice model. It provides a good description of the non-Gaussian spreading observed very recently in positron annihilation experiments. This new theory shows that the non-Gaussian distribution is a result of
Free volume distribution in crosslinked polyurethanes
β Scribed by A. E. Feinerman; Y. S. Lipatov
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 113 KB
- Volume
- 38
- Category
- Article
- ISSN
- 0887-6266
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β¦ Synopsis
Free volume distribution was studied for polyurethane networks differing in the molecular mass of oligopropylene glycol taken in the synthesis. To estimate the free volume distribution experimentally, inversed gel chromatography was proposed. The integral and differential distribution of the free volume was constructed. Experimental data for the crosslinked polyurethanes showed the difference in the value of the free volume and its distribution due to the varied packing of oligomeric chains in the regions of the molecular mass below and above the critical molecular mass of entanglements.
π SIMILAR VOLUMES
The free volume of a bisphenol-A-type epoxide oligomer (DGEBA) was studied using Williams-Landel-Ferry parameters and thermal expansion coefficients above and below the glass transition temperature (T g ). The values of the free-volume fraction at the T g are around 0.02 for the DGEBA oligomers havi
A cage implantation technique has been a d o p t e d i n a rabbit animal model t o investigate the biocompatibility of a n aliphatic crosslinked polyurethane based on hexamethylene diisocyanate (HDI). In this study, four cages are represented; the cage containing t h e candidate polyu r e t h a n e