Papers by Keyword: Rebound Resilience

Abstract: Deproteinized natural rubber (DPNR) latex is a modified version of natural rubber (NR) latex that is hypoallergenic and odorless when used in products. However, due to the lack of studies in this field, there are relatively few DPNR latex foam products to date. Our laboratory has developed a novel manufacturing technique that involves a heat-enzymatic reaction followed by a concentration procedure to generate DPNR latex directly from freshly tapped latex and to manufacture a novel DPNR latex foam using the Dunlop batch foaming procedure. To investigate the mechanical properties of the foam, ball-rebound resilience studies and compression tests were conducted on DPNR latex, commercial grade polyurethane (PU) and polyurethane memory (PM) foams as a comparison. Compressive stress-strain study revealed that the hysteresis loss ratio of DPNR latex foam, PU foam, and PM foam is 0.19, 0.66, and 0.86, respectively. DPNR latex foam exhibits the lowest hysteresis loss ratio due to its elastic behavior thus able to store a high amount of energy when under compressed. On the other hand, the rebound resilience of DPNR latex foam, PU foam, and PM foam is 74%, 29%, and 9%, respectively, indicating that DPNR latex foam has the highest rebound resilience. The resilience property is correlated with the elasticity, dimensional stability and durability of foam materials. Thus, DPNR latex foam is suitable for heavy-duty cushion applications including seats for transportation industry.

Abstract: Recently, aromatic oil (AO) is one of the substances that is typically used as a processing aid especially for high filler loadings in formulating rubber compound. Aromatic oil has disadvantages in that, it is hazardous to environment, toxic and has been labeled as carcinogenic. In this research, an epoxidised oil (EO) and aromatic oil were used to investigate the effect incorporation of oil onto the SBR/NR natural rubber vulcanizates (NR). From the result obtained, EO showed shorter cure time and scorch time as the oil loading were increased up to 20 pphr of EO. Physical properties such as hardness and rebound resilience of NR/EO vulcanisate were also investigated upon exposure to different humidity level in humidity chamber. At room temperature, the hardness of EO loading onto the SBR/NR vulcanisate is lower than AO loadings. Hardness was slightly decreased with increasing rate of humidity. There is great difference in hardness and rebound resilience values between AO and EO. Both hardness and rebound resilience were not affected by humidity. This implies the existence of good filler interaction with EO and rubber which do not impart changes in the hardness and resilience properties of rubber compound. Epoxidised oil has great promising potential to replace the carcinogenic aromatic oil as it has good overall performance and renewable in nature .

Abstract: The study about natural oils as processing aids in rubber was reported by several researchers for the past few years. The natural oils like rice bran oils, soybean oils, sunflower oils, vegetables oils and palm oils can be used as processing oils in rubber compounding [1-3]. These natural oils have been reported to have certain advantages compared to the petroleum based processing oils. In this study the potential of epoxidized palm oils (EPO) as additive and processing oils in carbon black filled styrene butadiene rubber was investigated. The main ingredients used were butadiene rubber (SBR), epoxidized palm oil (EPO) and carbon black. The vulcanized SBR rubber is then undergo several testing like swelling test, hardness and rebound resilience. An attempt was made to see whether the amount of EPO added to the SBR vulcanizates will affect the rebound resilience and swelling behaviour of the SBR vulcanizates. From this study, it was found that the compound contained higher EPO content tend to have lower rebound resilience, similar trend can be observed for hardness properties. While the crosslink density of the vulcanizates is decrease as the EPO content increases.

Abstract: A wood residual fiber foaming cushion material was prepared by using gathered wood fiber as main raw material, starch/PVA adhesive as matrix, adding a certain amount of foaming agent and related additives, hot compression molding to shape up. This paper makes an investigation of single factor on the product’s surface quality and related mechanical property. Results show that with the amount of wood residual fiber increases, the rebound resilience of the product first increases then decreases. The density decreases along with the amount of foaming agent increases. The compression strength and compression modulus of the product increases along with the amount of wood residual fiber increases, it decreases along with the amount of foaming agent increases.