Large inelastic deformation of glassy polymers. part I: rate dependent constitutive model

http://www.mate.tue.nl/mate/pdfs/5678.pdf

Mechanical performance of polymer systems: The relation between structure and properties

This work reviews the literature published over the last ten years on polymer mechanical properties as a function of molecular weight and molecular weight distribution, Thermal properties, stress-strain properties, impact, fracture, fatigue, creep, stress relaxation and cracking and crazing are examined for a wide variety of homopolymers and a limited number of copolymers. In general, mechanical properties increase as the molecular weight increases. However, above some limiting molecular weight the mechanical property is usually unaffected. Although much work has been done to describe the effects of molecular weight on mechanical properties, little quantitative correlation exists. The available equations to predict such properties as cracking and crazing, Tg, Tm and tensile strength from molecular characteristics are discussed in detail. However, a more quantitative description incorporating a wider range of mechanical properties would be more useful. This would facilitate use of the vast amount of information available and enable it to be applied more readily to new polymer systems.

Influence of molecular weight and molecular weight distribution on mechanical properties of polymers

http://www.mate.tue.nl/mate/pdfs/2320.pdf

On the origin of strain hardening in glassy polymers

Glass-rubber constitutive model for amorphous polymers near the glass transition

The effect of physical ageing on the properties of poly(ethylene terephthalate)

Ductile fracture of rigid poly(vinyl chloride)

The polymerisation of ethylene using magnesium reduced titanium trichloride catalysts, together with the usual aluminium alkyl activators is described. The previously reported high activity of this type of catalyst was confirmed. At 50°C and 1 atm. (1,01325 bar) pressure a value of 3,4.106 g dm3 (mol TiCl3)−1h−1 was obtained for the activity constant, a value about 102 times larger than for a conventional aluminium reduced TiCl3. On the other hand the viscosity-molecular weight-time (or conversion) relations are not very different from those given by conventional catalysts. Analysis of the results suggests that a high proportion (e.g. 50%) of the titanium atoms in the magnesium reduced TiCl3 functions as active sites.



Die Polymerisation von Athylen unter Verwendung eines mit Magnesium reduzierten Titantrichlorid-Katalysators, zusammen mit gewohnlichen Aluminiumalkyl-Aktivatoren, wird beschrieben. Die bereits berichtete hohe Aktivitat dieses Katalysatortyps wird bestatigt. Bei 50°C und 1 Atm. (1,01325 bar) Druck wird ein Wert fur die Aktivitatskonstante von 3,4.106 g dm3 (mol TiCl3)−1 h−1 erhalten. Dieser Wert ist ungefahr 102 mal hoher als derjenige eines auf ubliche Weise mit Aluminium reduzierten Titantrichlorids. Die Viskosotats-Molekulargewichts-Zeit (oder Umsatz)-Beziehungen sind nicht sehr verschieden von denen, die mit den ublichen Katalysatoren erhalten werden. Die Analyse der Resultate weist darauf hin, das ein groser Teil (z. B. 50%) der Titan-Atome im Titantrichlorid, das mit Magnesium reduziert wurde, als aktive Zentren fungieren.

R.N. Haward

Papers

The effect of physical ageing on the properties of poly(ethylene terephthalate)

Ductile fracture of rigid poly(vinyl chloride)

The polymerisation of ethylene with high activity magnesium reduced titanium trichloride catalysts in the absence of hydrogen

Effect of molecular weight on the thermal properties of polycarbonates

Dilute gelling systems: copolymers of styrene and glycol dimethacrylates