Energy Absorption Mechanisms and Impact Strength Modification in Multiphase Biopolymer Systems

A major drawback of some polymers is their low impact resistance and ability to absorb energy during fracture, such as PS, PMMA and PVC. Several techniques are used to toughen or modify impact resistance of brittle polymers, including reinforcement such as fibers and particles, or the incorporation of an elastomeric second phase. Whilst synthetic polymers can provide desirable properties for a wide variety of applications, there is a large environmental impact associated to those produced through petrochemical routes. Hence, in recent decades, much emphasis has been placed on polymer systems from renewable resources, as well as those able to undergo biodegradation due to enzymes and microbes. Blending of biopolymers is an area of high interest due to the promise shown in these materials and the potential for the replacement of petrochemical-based polymers, although the ability of these materials to absorb high levels of energy during fracture, whilst maintaining other acceptable mechanical properties, remains an issue. This paper presents a review of various patents about polymer, morphology development and impact strength modification, linking these topics to the formation of toughened biopolymer materials and blends.