𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Degradation of aromatic polymers—I. Rates of crosslinking and chain scission during thermal degradation of several soluble aromatic polymers

✍ Scribed by Shin-ichi Kuroda; Koichiro Terauchi; Kyohei Nogami; Itaru Mita

Publisher
Elsevier Science
Year
1989
Tongue
English
Weight
510 KB
Volume
25
Category
Article
ISSN
0014-3057

No coin nor oath required. For personal study only.

✦ Synopsis

Five kinds of aromatic polymers [polycarbonate(PC), polyarylate(PAR), polyetherimide(PEI), polysulfone(PSF), polyethersulfone(PESF)] were degraded at 380 ° in vacuum. The molecular weights and molecular weight distributions of degraded samples were measured by gel permeation chromatography, using dichloromethane as eluent. It was found that crosslinking takes place during degradation of each aromatic polymer studied; chain scission occurs simultaneously to a lesser extent. A novel simulation method, with theoretical calculation of molecular weights of the degraded sample, allowed evaluation of both the crosslinking rate and the chain scission rate. The crosslinking rate decreases in the order PEI>PAR>PC>>PSF~-PESF, and chain scission rate decreases in the order PC > PAR > PEI > PSF > PESF. It is suggested that the isopropylidene moiety and carbonate linkage increase the rate of chain scission, while the aryl sulfone moiety decreases the rate of radical reaction.

📜 SIMILAR VOLUMES

Degradation of aromatic polymers—III. Cr
Degradation of aromatic polymers—III. Crosslinking and chain scission during photodegradation of polysulphones
✍ Shin-ichi Kuroda; Ayako Nagura; Kazuyuki Horie; Itaru Mita 📂 Article 📅 1989 🏛 Elsevier Science 🌐 English ⚖ 458 KB

Bisphenol A polysulphone (PSF) and polyethersulphone (PESF) were photodegraded homogeneously at room temperature in an inert and a normal atmosphere. The average molecular weights and the molecular weight distributions of degraded samples were measured by means of GPC to evaluate the quantum yields

Degradation of aromatic polymers—II. The
Degradation of aromatic polymers—II. The crosslinking during thermal and thermo-oxidative degradation of a polyimide
✍ Shin-ichi Kuroda; Itaru Mita 📂 Article 📅 1989 🏛 Elsevier Science 🌐 English ⚖ 696 KB

A soluble polyimide (PI2080) was thermally and thermo-oxidatively degraded. Crosslinking was found to proceed under both conditions. Crosslinking densities of degraded samples were estimated before and after the gel point by gel permeation chromatography and by a new method using thermomechanical an