An alternative for producing thermoplastic elastomers (TPEs) with antibacterial properties is to add copper to the polymeric matrices. This study investigates the effects of the addition of copper microparticles on the morphological, thermal, physical and mechanical behavior and antibacterial properties of a blend composed by styrene-(ethylene-butylene)-styrene triblock copolymer (SEBS) and polypropylene (PP) homopolymer. The cooper microparticles used (commercial grade, produced by electrolytical process) were dispersed in a TPE matrix composed by SEBS/PP. Two bacterial species associated with infections (Escherichia coli and Staphylococcus aureus) were used in the antibacterial assays. The incorporation of copper microparticles in TPE matrix did not promote expressive changes in the thermal, physical and mechanical properties of the compounds. The findings from antibacterial assays showed a reduction of 99.99% in bacterial counts.

ABSTRACT The increasing concern over the spread of diseases has lead to a high consumption of antimicrobial additives in the medical and industrial fields. Since these particles can lixiviate from loaded materials, the contact between this additive and mammalian cells can occur during manufacture, use and disposal of the products. Silver on fumed silica (AgNP_SiO2) and titanium dioxide (TiO2) can be used as antimicrobial additives that are applied in polymeric formulation. While these additives can inhibit bacteria, fungus and virus proliferation; they may also be harmful to humans. Standard toxicological studies were undertaken using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide), CBPI (cytokinesis-block proliferation index) and micronucleus assay using different sets of additive concentrations. The nanosize of the samples evaluated was confirmed by transmission electronic microscopy. No significant micronucleus frequency increase or cell viability reduction were observed with the exposure of L-929 murine fibroblast cells to AgNP_SiO2 and TiO2 particles at any of the tested concentrations. The non toxic effect of the analyzed particles can be explained by considering its agglomeration tendency, composition, and crystalline form. Further investigations should be done to understand the interference of agglomeration and how it affects the toxicological study.

The purpose of the present study was to evaluate the antimicrobial potential of styrene-ethylene/butylene-styrene based thermoplastic elastomers (TPE) incorporated with zinc pyrithione (ZnPT) and silver nanoparticles (AgNano). Japan Industrial Standard was applied to evaluate the antimicrobial potential of incorporated TPE compounds against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Antifungal action was evaluated against Aspergillus niger, Candida albicans and Cladosporium cladosporioides. Samples prepared with ZnPT eliminated 99.9% of the E. coli and 99.7 % of the S. aureus population, and presented an inhibition zone in the fungal assay. Samples prepared with AgNano eliminated 99.7% of the E. coli and 95.5 % of the S. aureus population. There was no inhibition zone in samples containing AgNano; however, these samples did not present fungal growth on their surfaces. TPE samples containing ZnPT showed biocidal activity against the microorganisms tested and can be used to develop antimicrobial products.

Styrene-ethylene/butylene-styrene (SEBS) copolymer- based thermoplastic elastomers (TPE) are applied in the production of household items used in places with conditions for microbial development. Metal oxides like zinc oxide (ZnO) and others can be added to the TPE composition to prevent microbial growth. The aim of this study is to evaluate the effect of thermal accelerated ageing on mechanical, chemical and antibacterial properties of SEBS-based TPE containing 0%, 1%, 3%, and 5% zinc oxide. Zinc oxide was characterized by laser diffraction, X-ray diffraction, superficial area, porosity and scanning electron microscopy. Both aged and unaged samples were analyzed by infrared spectroscopy, tensile at rupture, elongation at rupture, hardness and antimicrobial activity against Escherichia coli and Staphylococcus aureus. Following thermal exposure, a reduction of antimicrobial activity was observed. No significant difference was observed in the chemical and mechanical characteristics between aged and unaged samples.

This study investigates the feasibility of using recycled high density polyethylene (HDPE) and wood fiber from species Eucalyptus grandis (EU) to manufacture experimental composite panels. The use of maleated polyethylene as coupling agent (CA) improved the compatibility between the fiber and plastic matrix. The mechanical properties of the resultant composites were compared with polymer with and without compatibilizer. The influence of the coupling agent (CA) in the polymer matrices and composites were evaluated at different concentrations, checking the physical, mechanical and thermal properties of wood plastic composites (WPC). Results of mechanical, physical and thermal properties showed that concentration of 3% w/w CA in the polymer matrices was that which showed the best results, but in the composites properties were very similar in all formulations. Based on the findings in this work, it appears that recycled materials can be used to manufacture value-added panels without having any significant adverse influence on material properties.