The basic scheme for autooxidation of polymers, originally developed by Bolland, Gee and co-workers for rubbers and lipids, is now widely applied to all types of polymeric materials. According to their scheme, the reaction that makes this process autocatalytic, referred to as the propagation step, is a hydrogen abstraction from the next substrate by the peroxyl radical (ROO˙ + RH → ROOH + R˙). ...

In our study we investigated the release mechanisms of coated oral dosage forms more deeply. The aim of the study was to monitor the buffer induced leaching out of water soluble compounds from Kollicoat SR films and to relate this process to the film properties and the release kinetics. Propranolol HCl tablets were coated with different amounts and ratios of polyvinyl acetate (Kollicoat SR) and...

OBJECTIVE To evaluate the use of a new spherical particle of polyvinyl alcohol and polyvinyl acetate (PVA-PVAc) for uterine artery embolization in patients with myoma with surgical indication. METHODS twelve patients underwent uterine myoma embolization with PVA-PVAc particles. Three to nine months later, they were submitted to laparotomy with myomectomy. We analyzed the following parameters:...

In this paper, research will be carried out to classify the blending behavior of glassy and rubbery polymer in solvent with amines. Commercially preface of a polymer prepared from a new monomer is uncertain and enormously expensive. A strategy to introduce new products into the market without a large investment is to take dissimilar polymers, amines and blend them together to make a new product...

Polylactic acid-g-polyvinyl acetate (PLLA-g-PVAc) was used as a compatibilizer for 50/50 starch/PLLA blend. PLLA-gPVAc with different mol% of PVAc contents were prepared by grafting PVAc onto PLLA backbone via free radical polymerization in solution process. Various conditions such as type and the amount of initiator, monomer concentration, polymerization time and temperature were studied. Resu...

The behavior of electron-rich alkenes in rhodium-catalyzed C-H activation/annulation reactions is investigated. Vinyl acetate emerges as a convenient acetylene equivalent, facilitating the synthesis of sixteen 3,4-unsubstituted isoquinolones, as well as select heteroaryl-fused pyridones. The complementary regiochemical preferences of enol ethers versus enol esters/enamides is discussed.