Biodegradability Study of Footwear Soling Materials in Simulated Compost Environment

Aim of the present study is to investigate the biodegradability and decomposing properties of footwear soling materials by standard biodegradability test method. Biodegradability tests were performed by aerobic exposure of the selected six soling materials to the soil matrix and measuring the degradation and decomposition occurred with time. All soling materials were characterized for physical and physicochemical properties such as weight loss, hardness, density, tensile strength, abrasion resistance, thermal and morphological properties before and after exposing to the simulated compost environment. In the present study, the end-of-life nature of footwear soling materials currently used by the footwear industries are explored, which will further emphasize the importance of development and use of biodegradable materials in the footwear manufacturing.

Fabrication of Bioplastic from Rice Straw

<p>Oil based plastics have been proven as severe pollutants for the environments as they required years to be degraded. Thus, bioplastics are very attractive as the solution of this problem as they easier to be degraded in soil. This work was aimed to fabricate bioplastics from rice straw, with addition of carboxymethyl cellulose (CMC) and glycerol. Prior to the bioplastic fabrication, cellulose was extracted from rice straw through digestion process using ethanol solution (50% w/w) and sodium hydroxide solution (8% w/w) as catalyst. Digestion process was held for 60 minutes at temperature of 120 ^oC. Bioplastics were produced by blending dried pulp, carboxymethyl cellulose, and glycerol. Five grams of dried cellulose was dissolved in 100 ml of water. The amount of CMC and glycerol added to the pulp solution were varied from 1 ml to 2 ml and 0.5 to 1.5 grams, respectively. Swelling test (both in water and oil) and biodegradability test were conducted to study the performance of the bioplastics. Results showed that bioplactic dissolved easily in water. During oil swelling test, it showed that higher glycerol content increases the oil proof characteristic of the bioplastic. Meanwhile, the CMC content has no impact during the oil swelling test. The best composition of the bioplastic was achieved with the CMC and glycerol contents of 1.382% (w/w) and 1,843% (w/w), respectively, with the lowest oil swelling test result of 55%. Biodegradability of the bioplactics were lower in higher CMC and glycerol contents. The best composition with maximum weight reduction of the bioplastics was achieved by the bioplastic with 0.469% (w/w) of CMC content and 0.939% (w/w) of glycerol.</p>

Fabrication of silver doped nano hydroxyapatite-carrageenan hydrogels for articular cartilage applications

It can be found from the results that nano hydroxyapatite- silver -3.0 wt% carageenan (nHA-Ag-CG3.0) improved the mechanical properties of the as-formed hydrogel scaffold after incorporation of higher CG concentration. The Young’s modulus of hydroxyapatite- silver - 1.5wt% carageenan (nHA-Ag-CG1.5) was found to be 0.36 ± 0.07 MPa that increased in case of nHA-Ag-CG3.0 demonstrating better interfacial compatibility of their matrix with respect to the reinforcement. This increase in reinforcement concentration resulted in higher stiffness that dissipated energy. The higher swelling ratio is envisaged to induce better cell adhesion and proliferation. The biodegradability test was performed in phosphate buffered saline at body temperature for 3 weeks. The biodegradability rate of nHA-Ag-CG1.5 was found to be equivalent to nHA-Ag-CG3.0 hydrogels at day 7 while it increased faster in nHA-Ag-CG3.0 on days 14 and 21 that may be ascribed to the possible interaction of nHA and Ag with their CG matrix. The bacterial cell viability of Staphylococcus aureus (S. aureus) was performed after 10 h, 20 h and 30 h of culture. The nHA-Ag-CG1.5 exhibited restrained growth of S. aureus as compared to nHA-Ag-CG3.0 and these results were validated by CLSM analysis. Hence, nHA-Ag-CG3.0 may be considered to have more cytocompatibility than nHA-Ag-CG 1.5.

Analysis of Biodegradable Films of Starch from Potato Waste

Starch was extracted from potato wastes and its peels to prepare bio-degradable films using glycerol and sorbitol at various concentrations of 35%, 45% and 55 (w/w) of dry starch. The properties of films prepared with modification techniques (hydrothermal treatment (HTT) and acid-alcohol treatment (AAT)) were analyzed. Biodegradability test was done by incubating with amylolytic bacteria (Bacillus lichneformis and Streptococcus bovis) for 24 hours and fungi (Aspergillus niger and Rhizopus stolonifer) for 72 hours. All microbial species were isolated from soil except S. bovis which was from calf stool and identified by conventional methods. The properties of modified starches were significantly different from non-treated starches. Tensile strength (10 N/m2) and elongation (9.47%) were significantly (p<0.05) superior in HTT starch films whereas solubility (25.8%) was superior in AAT starch films. Elongation (8.91%) and solubility (29.98%) were significantly (p<0.05) superior in 35% and 55% glycerol used films respectively but tensile strength (13.02 N/m2) was superior in 35% sorbitol used films. WVTR (999 g/m2/d) was higher at 91% RH in 55% glycerol used films. Micro-organisms used showed a significant effect (p<0.05) on biodegradation of starch based films. Highest degradation was observed by B. lichneformis i.e, 57.85% while A. niger had minimum of 25.13%. Films prepared with 35% glycerol was significantly (P<0.05) degraded by B. lichneformis i.e, 78.86%. Films prepared by using glycerol with acid alcohol treatment was significantly (P<0.05) degraded by S. bovis (55.57%). Although the starch of same variety of potato waste was not studied, results of the study suggest possibility of preparation of starch based bio degradable films potato waste and its peels by using glycerol and sorbitol.

Enhancement of Bio-plastic using Eggshells and Chitosan on Potato Starch Based

The extensive production of polymer plastics and their use in different commercial applications had burdened the municipal in cost and operation of the waste management system. This unwanted waste had also posed a significant threat to the environmental surroundings which destroyed biota. Hence, alternatives called bio-plastic evolved as the development of renewable resource by utilizing agricultural, eggshells and exo-skeleton seafood (chitosan) wastes instead of petroleum sources. The aim of this research is to use the eggshells and chitosan as fillers in potato starch to overcome the inherent drawbacks of bio-plastic. The experimental study was done on tensile strength, water absorption and biodegradability for potato starch-based bio-plastic with eggshells or chitosan. The results showed that by adding the eggshells into the potato starch-based bio-plastic had increased the tensile strength by 4.94% compared with chitosan only 1.28%. The reduction of water absorption by 10.95% was determined using eggshells as fillers. Meanwhile, the used of chitosan resulted in 27.59% reduction in water absorption. In eggshells, the weight loss in biodegradability test was 21.06% compared to chitosan of 7.9% within 20 days. It can be concluded that eggshells as fillers performed much better that chitosan in potato starch-based bio-plastic. It also can be deduced that adding fillers in starch-based bio-plastics can improve the bio-plastic performance.