Recent concern over the harmful effects on the ecology of long lasting plastics has led to heightened interest in the development of more environmentally sustainable materials. Attention has been paid to biodegradable thermoplastic polymers, polylactic acid (PLA) and polybutylene succinate (PBS). However, although these materials have been widely used as matrix in a composite, the potential of biopolymers as reinforcement in a composite structural system has been examined less. Two types of unidirectional biodegradable composites, PLA self-reinforced and PLA reinforced PBS matrix composites, were produced. The composites were tested for Young's modulus, tensile strength and strain at break. Cross-section and fracture surface characteristics of the composites were also examined by scanning electron microscopy to identify damage modes. It is found that the tensile strength of both PLA self-reinforced and PLA-PBS composites is increased by 10-40%, while their initial modulus is 2-6 times higher than that measured for PLA and PBS films.

The reuse of comminuted glass-fiber-reinforced resin with various granularities gathered from printed circuit manufacturing residues was investigated. As fillers, these residues were converted into polymeric composite board by an extrusion and injection process using polypropylene as a bonding agent. The mechanical properties of the reproduced composite board were examined by considering the effects of mass fraction and glass-fiber distribution. Interfacial-layer micrograph analysis of the composite material fracture surface was used to study the fiber reinforcement mechanism. Results showed that using comminuted glass-fiber-reinforced resin as a filler material greatly enhanced the performance properties of the composite board. Although the length and diameter of filler varied, these variations had no appreciable effect on the mechanical properties of the processed board. Maximum values of 48.30 MPa for flexural strength, 31.34 MPa for tensile strength, and 31.34 J/m for impact strength were achieved from a composite board containing mass fractions of 30, 10, and 20% glass-fiber-reinforced resin waste, respectively. It was found that the maximum amount of recyclate that could be added to a composite board was 30% of weight. Beyond these percentages, the materials blend became unmanageable and the mixture less amenable to impregnation with fiber. Presented studies indicated that comminuted glass-fiber-reinforced resin wastefilled polypropylene composites are promising candidates for structural applications where high stiffness and fracture resistance are required.

REPREG materials (PM) which are reclaimed from waste printed circuit boards industry was used to produce polymeric composites by an extrusion and injection process through adding polypropylene (PP) as a bonding agent. The results show that the increments of tensile strength, tensile modulus, flexural strength and flexural modulus of the PP composites are greatly achieved than unfilled PP. The maximum content of waste PM in polymeric composites was 30 wt%, of which the strength of tensile, flexural and impact properties could reach to 25.43 MPa, 48.30 MPa and 11.81 J/m respectively. This technique provided a promising method to reuse fiber-reinforced polymeric and expanded to composite plastic waste.