A study of polymer film brittleness

Abstract

The inability of polymer chains to deform the required amount within the time allowed by a stress‐to‐failure event results in brittle failure. Factors related to brittle behavior of films were investigated. By both conventional and novel testing techniques, stress–time–temperature relationships were studied to determine the brittle point. From high‐speed tensile tests at strain rates up to 106%/min., the critical strain rate (incipient brittleness as indicated by failure accompanied by a marked decrease in ductility) was determined for representative films. High‐speed motion pictures (6,000 frames/sec.) of film failure in rice bag drop tests, were used to ascertain the time of deformation to be related to brittleness. Deformation rates were calculated to be of the order of 130 to 230 × 103%/min.

Development of methylcellulose‐based sustained‐release dosage by semisolid extrusion additive manufacturing in drug delivery system

“…Thus, the weight uniformity of MC 12% (wt/wt) tablets was worse than tablets with other two concentration levels. The poor extrudability and fluidity was related to the high magnitude of yield stress and G', and the relatively low value of tan δ 31,32 . Accordingly, 10% (wt/wt) was determined as the optimal concentration for MC as the 3D printing materials, regardless of theophylline dosages.…”

“…The poor extrudability and fluidity was related to the high magnitude of yield stress and G', and the relatively low value of tan δ. 31,32 Accordingly, 10% (wt/wt) was determined as the optimal concentration for MC as the 3D printing materials, regardless of theophylline dosages. Pastes at this concentration can be easily extruded from the nozzle without breakage due to relatively low viscosity, and K. This printed paste also had better shape retention and minimum visible defects with relatively high G' and yield stress.…”

Tensile Properties of Highly Filled Magnetic Polymeric Composites

“…In rigid polymers, the elongation to break generally decreases as the testing speed increases [18,19]. However, with rubber the elongation often increases as the rate of elongation increases [20][21][22].…”

Polymer structures and properties of new heat resistant films and fibers

“…If "pre"-polymer (in solution, in form of films, fibers, or fabrics) is subjected to such 'post" reaction, it will often proceed without crosslinking and will afford the final polymer in solution or in form of films, fibers, or fabrics ( Figure 1 ) . Poly (hydrazides) give poly (oxadiazoles) (4), poly-(amide acids) give poly (imides) (6), poly (amino amides) give poly (benzimidazoles) (9,lO) by cyclodehydration reactions. Other cyclization reactions afford poly (N-phenyl triazoles) ( 13) from poly (hydrazides) by reaction with aniline.…”