 |
|
Predicting the viscosity of low VOC vinyl ester and fatty acid-based resins
U.S. Government
Paperback. Books LLC, Reference Series 2011-09-28.
ISBN 9781234070090
|
|
|
|
Buy from Amazon.co.uk
|
Publisher description
Original publisher: Aberdeen Proving Ground, MD : Army Research Laboratory, [2005] OCLC Number: (OCoLC)710807769 Subject: Gums and resins -- Viscosity. Excerpt: ... monomers. The peak representing Epon 828 appeared at 15.5 min. The lower retention time of the vinyl-ester peak ( 14.5 min ) indicates that the epoxy reacted with methacrylic acid to form a higher molecular weight species ( i.e., vinyl ester ). The peak at 18 min represents low molecular weight species, such as styrene, methacrylic acid, and catalysts. Previous work has shown that if a significant amount of epoxy homopolymerization occurred, a broad peak appearing at 10 min and lower elution times would appear ( 27, 28 ). Because no such peak appeared in our prepared vinyl-esters, we conclude that no epoxy homopolymerization occurred. SEC analysis of the methacrylation of epoxies as a function of time showed that the peak at 18 min decreased with reaction time, while the vinyl-ester / epoxy peaks shifted to lower elution times. The peak at 18 min decreased to less than 95 % of its original size when the methacrylation was run without styrene, as was done when preparing vinyl ester 828. These results conclusively show that Epon reacted with the methacrylic acid to form higher molecular weight vinyl-ester monomers. To measure the molecular weights of vinyl-ester resins using SEC, the molecular weight as a function of retention time was calibrated using Epon resin samples ( 29 ). The number average molecular weight of the Epon 100XF resins is known through epoxy titration results. The calibration curve relating peak retention time to Epon molecular weight was constructed and used to calculate the number average molecular weights of the vinyl-ester peaks. For the bimodal blends, the relative areas of the peaks and the two different number average molecular weights were used to simply calculate the number average ( M ) and weight average molecular n weights ( M ): w n M + n M high high low low M =, ( 1
More books by U.S. Government
Similar books
Rate the book
Write a review and share your opinion with others. Try to focus on the content of the book. Read our instructions for further information.
Predicting the viscosity of low VOC vinyl ester and fatty acid-based resins
Book reviews » Predicting the viscosity of low VOC vinyl ester and fatty acid-based resins
|
|
 |
|
|
|
|
