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The banana stem fibre is added to natural rubber (NR) latex compound in order to increase the biodegradability of NR latex products. Banana stem fibre was soaked in 2% of sodium hypochlorite solution for 24 hours at 40°C. After that, it was ball-milled with variable milling times (0, 24, 48 and 72 hours) to produce a series of banana stem fibre dispersions containing 10% fibre of different particle sizes. The resulting dispersions were added to NR latex compounds. The effect of milling time on the fibre size of the dispersion and the properties of the NR latex films was studied. It was observed that the particle size of the banana stem fibre reduced with milling time. NR latex films containing smaller banana stem fibre particles have higher moduli (at 100% and 300% elongation), higher tensile and tear strengths. Except for the milling time for 24 hours, increasing the milling time reduces the swelling index of the NR latex films. Ball milling the banana steam fibre for 24 hours produced fibre whiskers which increase the interaction between the banana stem particles with rubber matrix. [ABSTRACT FROM AUTHOR]

Biodegradable sago starch-filled natural rubber latex films were subjected to soil decomposition. Decomposition indicators such as temperature, soil pH and humidity, and volume of carbon dioxide and oxygen were monitored via an electronic sensor network (ESN) control chamber. During the assessment, the environmental temperature was kept constant and a small increase in soil humidity was detected. The ESN control chamber detected the increment of soil pH and carbon dioxide level and a decrease in oxygen content during the biodegradation process. The changes in these parameters confirmed the progress of the biodegradation process. The mass loss retention for films was compared with data obtained from the ESN control chamber to get the coefficient of correlation (r) value, which describes the relationships between the two datasets. Scanning electron microscopy images confirmed the formation and growth of microorganism colonies, and Fourier transform infrared analysis indicated the breakage of double-bonded carbon in sago starch-filled natural rubber latex films and carbonyl group intensification, signifying the formation of aldehyde and ketone groups after the fourth week of soil decomposition. [ABSTRACT FROM AUTHOR]

The effects of partial or complete replacement of two commercial fillers, carbon black (CB) and silica on cure characteristics, tensile properties, fatigue life, morphological properties, and rubber-filler interaction of paper sludge (PS) filled natural rubber composites were elucidated. Compounding was carried out on a two-roll mill with total filler loading of 30 phr. Results indicate that maximum torque, tensile strength, elongation at break, tensile modulus, and fatigue life increased the cure time while the scorch time decrease with increasing carbon black loading ratio of PS/CB filled natural rubber composites. On the other hand, increased loading of silica in PS/silica weight ratio resulted in an increment in cure time, scorch time, maximum torque, elongation at break, and fatigue life but not significantly altering tensile strength and tensile modulus of the natural rubber composites. In addition, PS/silica filled natural rubber composites exhibit lower maximum torque, tensile properties, and fatigue life compared to the PS/CB filled natural rubber composites. Rubber-filler interaction and SEM micrograph studies proved that the higher interaction between carbon black and natural rubber occurred in PS/CB filled natural rubber composites rather than PS/silica filled natural rubber composites. [ABSTRACT FROM AUTHOR]

Starch-graft-acrylonitrile (ANS) is compounded with carboxylated nitrile butadiene rubber (XNBR) latex. The control XNBR and the ANS/XNBR latex films were prepared through a coagulant dipping process. The films were subjected to ageing and soil burial procedures. For the biodegradation experiment, the surface of the film was assessed after the 2nd, 4th and 8th week of soil burial. The ANS, XNBR, and ANS/XNBR colloidal stability were determined with a Malvern Zetasizer. For the dipped latex films, the mechanical, morphological and thermal properties were analyzed. The addition of ANS into the XNBR latex increased the stability of the colloidal dispersions, decreased the latex film tensile strength, but increased the elongation at break due to the bipolar interaction of the ANS and XNBR particles. The ANS/XNBR latex films aged faster than the control films while the morphological analysis showed the existence of a starch crystal region and the formation of microbial colonies on the surfaces of the films. Based on the TGA-DTA curves, a higher ΔT was observed for the ANS/XNBR latex films signifying high thermal energy needed for the film to thermally degrade., (Copyright © 2015 Elsevier Ltd. All rights reserved.)