Natural rubber modification as a pre-vulcanized latex impregnated with TiO2 for photo-catalytic degradation of gaseous benzene

Natural rubber latex films with effective growth inhibition against S. aureus via surface conjugated gentamicin

Hospital-associated infections and related complications are of extreme concern in the healthcare sector since biofilms generated over material surfaces not only create turbulence in the healthcare practices followed but also ruin the device performance, and increased medication, leading to significant chances of drug resistance. Natural rubber latex (NRL) being the first choice for the manufacture of several conventional biomedical devices, it is essential to ensure the surfaces of the same are inherently inactive against most microorganisms. This study presents NRL film surface conjugated with a well-known antibiotic, gentamicin through an amide linkage to generate antibacterial activity to the surface with a significant growth inhibition rate, especially against Staphylococcus aureus. The NRL films were surface-oxidized under controlled acidic conditions to generate carboxyl groups exploring the unsaturation of the base monomer unit. The carboxyl group reacts with the amine groups of gentamicin facilitating its surface conjugation. The surface anchoring was authenticated by FTIR-ATR complimented further by contact angle measurement as a function of hydrophilicity and elemental analysis by EDX spectroscopy. The antibacterial efficacy of modified NRL films was evaluated using antibacterial drop test and the results indicated a substantial growth inhibition rate (>60%) against Pseudomonas aeruginosa and Staphylococcus aureus. The study could be further optimized and proposed as a viable route for the conjugation of active molecules over inert polymer molecules.

A facile approach to fabricate room temperature intrinsic self-healing fabrics

Self-healing fabrics have garnered a lot of attention due to their recovering functionality upon damage. This work describes a facile technique for developing a novel self-healing coating with the goal of producing autonomous intrinsic self-healing fabrics that can recover from damage at room temperature without the use of external stimuli. The coating was developed using natural rubber latex (NRL) and consisted of a dynamic reversible metal thiolate ionic network. The formation of the reversible ionic network was assessed by Differential Scanning Calorimetry (DSC), Ultraviolet-visible spectroscopy (UV-vis), Fourier Transform Infrared (FTIR) and zeta potential analysis. Scanning electron microscope (SEM) images revealed that the coating impregnated the fibres of the fabric and improved their structural integrity. The morphology of the punctured area revealed that intermolecular diffusion had occurred during the recovery and the sample had completely healed. The results also showed that the tensile strength, tear strength and puncture strength of the fabric achieved 100% healing efficiency when the damaged fabrics were brought into contact with each other and allowed to be healed at room temperature. This technology is expected to open up a new avenue in the textile industry.

Photocatalytic Oxidation of PLA/TiO2-Composite Films for Indoor Air Purification

Non-decomposable plastic has been replaced with polylactic acid, which is a biodegradable aliphatic polyester stationary phase, in composite films embedded with a TiO₂ photocatalyst for mitigation of indoor air pollution. PLA has superior properties relative to those of other biopolymers, such as a relatively high melting point, crystallinity, and rigidity. This study aimed to incorporate TiO₂-anatase into PLA for use as a photocatalyst using the blown film method. Photocatalytic oxidation, an advanced oxidative process, has been recognized as an economical technique providing convenience and efficiency with indoor air treatment. Therefore, the use of new environmentally friendly biodegradable polymers provides an alternative way to address the severe environmental concerns caused by non-decomposable plastics. UV-vis spectrophotometry and scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX) were used to observe the dispersibility and mixing capacity of the TiO₂-anatase PLA matrix. TiO₂ dosages were 5, 10, and 15% (wt/wt), and they were incorporated with a twin-screw extruder. SEM-EDX images demonstrated the homogeneity of TiO₂ distribution in the PLA matrix. The energy band gaps of TiO₂ in the PLA/TiO₂-composite films were between 3.14 and 3.22 eV. The relationship between the photocatalytic oxidation rate and the TiO₂ dosage in the PLA/TiO₂-composite films was determined. A prototype reactor model is geared toward the development of air purifiers for indoor air conditioning. Rate constants for benzene degradation were obtained using first-order kinetics to find rate constants matching experimental findings. In the PLA/TiO₂-composite film, the TiO₂-anatase photocatalyst was able to degrade 5 ppm benzene. This work contributes to the use of ecoefficient photocatalytic oxidation.