Change of mechanical properties of rigid poly(vinylchloride) during photochemical ageing

• Published in: Journal of materials science Vol. 34; no. 2; pp. 379 - 384
• Main Authors: ANTON-PRINET, C, MUR, G, GAY, M, AUDOUIN, L, VERDU, J
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 15.01.1999; Springer Nature B.V
• Subjects: Ageing; Applied sciences; Carbonyls; Chain scission; Crosslinking; Ductile-brittle transition; Elongation; Exact sciences and technology; Materials science; Mechanical properties; Physical properties; Polymer industry, paints, wood; Properties and testing; Rigid PVC; Spectrophotometry; Technology of polymers; Zinc Compounds; Calcium Compounds; Heat stabilizer; Embrittlement; Mechanical properties; Temperature effect; Tensile property; Experimental study; Ductile brittle transition; Additive; Artificial ageing; Polyvinyl chloride; Photochemical degradation; Thermal degradation
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1023/A:1004482328203

Thermally stabilised, unpigmented, rigid PVC samples, were exposed to accelerated photoageing at 40°C, 55°C and 70°C. The concentration profiles of photoproducts were determined on microtome slices (∼ 20 μm) parallel to the irradiated surface using IR (carbonyls) and UV (polyenic double bonds) spectrophotometry and by steric exclusion chromatography (Mn and Mw). They indicate that carbonyls and chain scissions predominate only in a thin superficial layer whereas polyconjugated double bonds and crosslinks predominate in a subcutaneous layer (∼300–400 μm). Tensile measurements show that the ultimate elongation decreases after an induction period whose duration is a decreasing function of temperature. The change of mechanical behaviour can be described in terms of a ductile-brittle transition shift mechanism in which crosslinking plays an important role. A tentative explanation of a such crosslinking induced transition is proposed in the discussion.