Rapid method for the determination of molecular weight distribution in high polymers: A thermal gradient-turbidity technique

✍ Scribed by Leon W. Gamble; W. Todd Wipke; Trent Lane

• Publisher: John Wiley and Sons
• Year: 1965
• Tongue: English
• Weight: 681 KB
• Volume: 9
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1965.070090425

✦ Synopsis

A rapid method for determining the molecular weight distribution of polymers has been the aim of polymer chemists for a long time. The method presented here requires less tban two hours, including dissolution of the polymer. It is an exteneion of a photoelectric turbidimetric technique presented by Taylor and Tung in 1961. The equipment has been completely redesigned and presently consists of a copper block containing a turbidity cell, optical system and attendant electronic circuitry for measuring relative changes in turbidity of polymer solutions aa a function of temperature. An X-Y recorder is used t o plot turbidity versus temperature. A parameter determined from the plot is correlated with a meaaure of molecular weight distribution determined on known samples for each type polymer by another means. Baaed on this correlation unknown samples may be analyzed. The instrument is eaay t o operate and has shown excellent stability over a two year period. Polymers studied by this technique include ethylene-propylene copolymer (EPR), polypropylene, polyethylene, and butyl, however, the only results to be reported here are those on ethylene-propylene copolymer.