THE EFFECT OF LEATHER FIBERS ON VULCANIZATION BEHAVIOR OF NATURAL RUBBER

This paper shows the primary research results of the effect of the leather fibers on the vulcanization of natural rubber (NR). The fibers used in this research were prepared by grinding waste leather scraps of Vietnam shoe making company. Leather fibers (LFs) and natural latex rubber were mixed together at various rates by a stirring machine. The obtained composites of natural rubber containing leather fibers were dried at pleasant condition prior to the analysis. Vulcanization behavior of the samples was clarified using a moving die rheometer. The vulcanization temperature as 120 °C is found to be the appropriate temperature for the NR/LFs composite. The increasing of minimum and maximum torque with the increasing of leather fiber content shows the improving in stiffness of natural rubber with the presence of leather fibers. Regarding to curing curves, 40 wt% promises to be the optimal leather fiber content to reinforce natural rubber.

Cure Characteristics, Tensile and Physical Properties of Recycled Natural Rubber Latex Glove (NRL-G) Filled Acrylonitrile Butadiene Rubber

The use of recycled natural latex rubber glove (NRL-G) as a reinforced material filled acrylonitrile butadiene rubber (NBR) was studied. The compounds of different NRL-G loading (0, 10, 20 and 30 phr) were prepared by using two roll mills at room temperature. Two different size ranges of NRL-G such as 300μm-700μm (fine) and 2cm-4cm (coarser) were used. The properties such as cure characteristics, tensile and physical properties were determined. The NBR/NRL-G compound with the fine size of NRL-G exhibits overall good cure characteristics and physical properties compared with coarser size. The addition of the of 20 phr content NRL-G (fine) contributed to the optimum tensile properties than coarser size.

Quality Improvement and Characteristics of Polyhydroxyalkanoates (PHAs) and Natural Latex Rubber Blends

Biopolymers of hard, brittle and low flexible polyhydroxyalkanoates (PHAs) and a soft and high elastic natural-latex rubber are blended at room temperature by using a combination technique. Concentrations of the PHAs solution are constituted at 1%, 2% and 3% w/v and mingled with fresh natural latex in different ratios (PHAs : Latex Rubber = 0:10, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1 and 10:0). After vigorous blending, forming polymeric sheets leave a dried-film pattern. Only the best 3 different ratios (4:6, 5:5 and 6:4) are selected by evaluating morphological-based information. These lead to actually define and characterize for their morphological and mechanical properties. The morphological attributes are exemplified by polarized optical microscopy and X-ray diffractometry (XRD) while the thermal characterization is determined by differential scanning calorimetry (DSC). Morphological analysis for the criterion of blending achievement indicated that there is a significant relationship among porosity, texture and shrinkage. The porosity shows obviously low to high for gradually increasing PHAs and decreasing the latex. Thus, dense texture and shrinkage relate to blending compositions between PHAs and latex. The XRD and DSC reveal certain aspects of decreasing crystallinity arising from enhancing of the latex content. A high degree of crystallinity and melting temperature relates to greater PHAs ratio. The mechanical investigations have revealed complex localization patterns of tensile strength and elastic modulus. The more PHAs concentration at 2% w/v indicates the greater elastic modulus than 3% and 1% w/v. Significant differences are found on polymeric composites of mechanical analyses between PHAs and natural latex. The constituted superiority in the ratio of 5:5 significantly differs in extension to break. Additionally, both tensile strength and elastic modulus of 2% w/v PHAs present the maximum value among them.

Reinforcement of Natural Latex Rubber by Carbon Black and Ionizing Radiation

The study of the reinforcement of rubber by carbon black has made it possible to establish the radical nature of the interaction, thus explaining why, in the latex phase and in the absence of sources of radicals, the reinforcing effect of carbon black does not exist and why it has been possible up to the present to obtain it only by mastication of the solid rubber in the presence of black. Irradiation, an excellent source of radicals, should in latex systems lead to a reinforcement of rubber by black. The experiments carried out appear to prove this. Irradiation of the latex and the black in aqueous dispersion, followed by a mixture of the two constituents which is then poured out on a plate, dried and subjected to moderate thermal treatment, makes it possible to obtain mechanical properties which are definitely superior to those of films prepared without irradiation and of films vulcanized with sulfur.