Structure and Properties of Styrene butadiene rubber
While most of the properties of SBR are comparable with NR, but in some respects like heat build-up, tack and gum tensile strength make it inferior to natural rubber. Other disadvantages include: Low elongation at break Low hot tear strength Hysteresis, resilience But the addition of resins and reinforcing fillers adequately improve these properties. However, there are properties which makes it superior over natural rubber. These include: Better process ability, Slightly Better heat aging Better abrasion resistance and resistance to degradation (under heat) Also, scorch problems are less likely to occur with SBR than with NR. Overall, the most important factors in the commercial viability of SBR making it material of choice over other rubbers are: Wide availability Low cost compared with those of all other synthetic rubbers, Ability to accept high filler levels, Relatively stable price compared with that of NR and Overall properties on a cost/performance basis Rubber…
Styrene butadiene rubber categories in terms of production and polymerization methods
Emulsion method In this method, polymerization is done through free radicals, which is done in both hot and cold states. The product obtained by cold method in the presence of oil or in the presence of oil-soot has high linearity, narrow molecular distribution, high molecular mass and difficult processing. The product obtained by hot method is also highly branched and has a wide molecular mass distribution, good process ability and higher percentages of 1 and 2-vinyl. Solution method In this method is ion polymerization, the product of this method has high linearity, high flexibility and high abrasion and tear resistance against dynamic stresses. Gel method The product of this method has a weak percentage of chemical bonds during the polymerization reaction between the chains, which reduces the mobility of the chains and improves processability. cooking methods It is mainly done by sulfur vulcanization method. The cooking speed in the SBR…
Rubber dandelions
Today’s tires are a combination of synthetic tires and natural tires made from rubber trees. But researchers have succeeded in extracting a substance from the dandelion plant that is used to make tires. Dandelions are practically unused plants except for use in a variety of salads, herbal drinks and some beverages. At least until now. But a Russian species of the plant, called Taraxacum kok-saghyz, or TKS for short, could revolutionize the rubber industry. Dandelions are practically unused plants except for use in a variety of salads, herbal drinks and some beverages. At least until now. But a Russian species of the plant, called Taraxacum kok-saghyz, or TKS for short, could revolutionize the rubber industry. Despite the invention of synthetic tires, like all synthetic materials that absorb natural raw materials, these tires are strong and resilient to natural tires. This is because natural rubber molecules, which are the product of…
Whatever we should know about low density polyethylene?
Low-density polyethylene – LDPE is terminologically composed of two terms monomer meaning single part and ethylene which is a hydrocarbon with the formula C 2 H 4. Lightweight polyethylene was produced in 1933 under very high pressure and along with the radical release of polymerization by the British company ICT. Also, the rate of degradability of this material in nature according to the EPA or environmental protection test is equal to 5.7%, which is determined by the degradability number 4. Despite the fact that many polymer products have been produced and industrialized in global markets, today LDPE is considered as one of the most important products in the plastic industry, so that in 2013, the revenue of this product in the markets around the world was about $ 33 billion. it is arrived . Properties of lightweight polyethylene – LDPE LDPE densities range from 0.91 to 0.940 g / m3.…