Effect of molecular weight on brittle‐to‐ductile transition temperature of polyetherimide

Abstract

ABSTRACT:The fracture and yield strength of polyetherimide was evaluated over a temperature range of 23 to 140°C for materials with number-average (M n ) and weightaverage molecular weight (M w ) ranging from 15.6 to 22.8 and 36.6 to 52.3 kg/mol, respectively. The brittle-to-ductile transition temperature, where an equal probability exists that an impact will result in a brittle or ductile failure, was determined by evaluating the temperature at which fracture and yield strength are equal. The transition temperature decreased from 155 to 60°C with increasing molecular weight and provided a measure of relative ductility between material samples. As a case study, the practical impact strength of an injection-molded food service tray was determined at 20°C and correlated with fracture strength as a function of molecular weight.

Thermal degradation of polyetherimide joined by friction riveting (FricRiveting). Part I: Influence of rotation speed

“…Although variations in average MW normally influence polymer strength, this was not observed for the investigated joints [24]. This minor decrease in molecular weight can be considered irrelevant for the mechanical performance of the joints because it is either above or within the molecular weight range where the strength of the PEI polymer is independent of the variations in this property [45]. The thermal degradation behaviour was further studied by FTIR analysis.…”

“…Sanner et al [45] studied the effect of different molecular weights on PEI ULTEM's mechanical properties. For a molecular range varying from M n ¼ 15,660 to 22,820 g/mol and M w ¼ 36,640 to 52,300 g/mol, the tensile strengths at temperatures ranging from 23 to 140 C were not strongly altered.…”

“…Experimental molecular weight results plotted over the molecular weight intervals (hatched areas) where the tensile strength of PEI Ultem 1000 is not strongly influenced by this variable[45].…”

Amelioration in physicochemical properties and single cell performance of sulfonated poly(ether ether ketone) block copolymer composite membrane using sulfonated carbon nanotubes for intermediate humidity fuel cells

“…The heavier the chain is, the greater is its contribution to the overall molecular weight. It may be correlated to the mechanical properties (eg, tensile strength, etc) and processing of the polymer . M z is a measure for the high‐order molecular weight and may influence the elasticity of the polymer .…”

Nanomechanical and surface frictional characteristics of a copolymer based on benzoyl-1,4-phenylene and 1,3-phenylene

“…The PC M w measured by light scattering (absolute method) is reported as 26,300, while the relative M w determined by GPC using polystyrene standards is reported as 57,000 [23]. PEI relative M w measured by GPC using polystyrene standards is reported as 52,000 [24]; actual molecular weight is in the range of 20,000-30,000 [25]. Mica discs (9.9 mm diameter, Ted Pella, Inc.) were used as the substrate for PS and SRP films.…”