Properties of PVC/ABS blends

Properties of PVC/ABS blends Introduction Polymer blending is one of the fastest growing areas of polymer technology. Blending of polymer has become an increasingly important technique because it is an economical, viable and versatile way in which new material can be produced with a wide range of properties by merely using conventional processing equipment such as extruder or internal mixer. Polyvinyl chloride is most versatile material in plastic family and second largest consumption material in plastic industries compared to polyolefin’s. It is characterized by rigidity, hardness, excellent tensile modulus and low cost. However, it has low impact strength and poor thermal stability. Which limit’s it’s used. Similarly, Acrylonitrile-Butadiene-Styrene (ABS) is one of most largely used engineering plastics. It has excellent mechanical, thermal, electrical & chemical properties. Followed by inferior properties such as poor weather resistance, highly flammable and merely high cost. Polyvinyl c hloride is largely blended with number of polymers and rubbers. In most cases, to improve properties of PVC and rarely to improve properties of other materials. One of most inferior properties of PVC is low impact strength. To overcome this problem, it is blended with many rubbery materials. It has been shown that impact strength of PVC increases by blending with rubbery material such as NBR, SBR etc. But, it follows the decrease in tensile strength, rigidity and in most cases thermal stability. Hence to achieve high impact strength, better thermal properties along with rigidity, PVC is blended with ABS. The blend of PVC and ABS posses their advantage of impact strength, rigidity, chemical resistance, electrical properties and overall low cost. In ABS, generally the rubbery phase is made of emulsion polymerized polybutadiene, which constitutes the main polymer chain. The glassy phase is made of styrene and acrylonitrile grafted on Polybutadiene. Thus, it combines the impact strength of rubber and tensile strength, heat stability of styrene Acrylonitrile (SAN) Matrix. Thus properties of styrene acrylonitrile (SAN) and polybutadiene are imparted in PVC/ABS blend. Compatibility of Polyblend of PVC/ABS blends Compatibility is characteristics, which shows that components of blends are soluble in one another in all proportion. However, compatible blends are susceptible to phase separation at elevated temperature. While preparing blend, it is necessary to consider compatibility of components of blend with each other, which are used to prepare blends. In case of PVC/ABS blend, PVC and ABS are used as blend components. ABS is made by emulsion polymerization of SAN grafted by Polybutadiene. Polystyrene and Polybutadiene, have solubility parameter close to PVC. Although, solubility parameter of PS and Polybutadiene are close to PVC, they do not have good compatibility because of their being non-polar nature. While Acrylonitrile imparts good compatibility because of itâ⠂¬â„¢s polar nature (as shown in table). Solubility parameter of components of PVC/ABS blend    Yodouchi and Seto reported that in ABS material, the brittle and glassy component ( PS and SAN) improves tensile strength while Polybutadine contribute to toughness. The mechanical properties have been shown to be affected by type of ABS used, due to different Polybutadiene content.

Effect of e-readers on the publishing industry Assignment

Effect of e-readers on the publishing industry - Assignment Example ed that social exchange theory is taking place on an international level as the humanity has learned the art and science of communicating across cultures and borders. The internationalization of communication and socialization is identified as essence of the notion known as global village (Graham 1998). In recent years, leading technological companies have launched devices that have been blessed with the capability of helping people in accessing and downloading books and other kinds of literature. The old fashion and traditional practice of reading books in a printed format is ending. Major number of publications is being provided to public in an electronic format while the most used format is called Portable Document Format (PDF). The conventional method of providing printing books got very expensive and therefore, the major publishing companies such as McGraw Hill initiated to provide publications in an electronic format. The basic and fundamental purpose of using electronic devices as sources of accessing literature is to drive down the production costs whereas, the end readers are also provided with significant level of cost advantages. In summary, it can be urged and argued that availability and cost of printed information has notably increased and decreased respectively (Pan & Leidner 2003). The current period, the customers and common peoples information has considerably risen and therefore, companies and governments are facing problems in justifying their filthy practices from public. The publishing companies are offering books and research journals in e-format and they provide printed copies on special request only. The supporters of high involvement of technology in knowledge management argue that human mind is well accustomed to understanding materials in print format. They also suggest that human sensory centers are experiencing growing and noticeable level of stress because of focusing on screens. But, these potential disadvantages will subside as

Economy in Russia Essay Example | Topics and Well Written Essays - 2000 words

Economy in Russia - Essay Example Russia has to deal with persistent economic problems, which include: The consensus and eventual policy position taken in Russia was that in order for the Russian economy to develop and benefit from the increasing integration of the global market and trade, policy reforms must be instituted. These reforms should directly address the challenges cited above. The past few years saw policy pronouncements that include price reform, the privatization of enterprise, macroeconomic stabilisation and fiscal decentralisation. Beginning in 1992, the government began instituting economic reform in these areas and based on the trajectory of growth of the Russian economy up to the present, it is clear that some of the governmental policies have worked. Terterov (2004), for example, cited how investments to the country has overtaken capital flight, which has been the pattern in the past. As a result the economy has received a substantial boost, particularly in manufacturing and industrial sector, helping to create jobs and revenue for the state (Terterov 2004). Empirical research has also shown the positive link between governmental reform and wage increase and unemployment (Gerber 2006). Wolf and Lang (2006) in a study for the RAND Corporation reported that the recent impressive economic performance can be attributed to decentralized decision-making and the change in resource allocation from the previous state and bureaucratic allocation to the resource allocation through the market. During Vladimir Putin’s administration, Russia was finally recognized as a market economy. The United States and the European Union declared this in June 2012. This is important for Russia because being classified as one means better opportunities for trade with other countries. For example, as a result of the recognition, the United States has removed several restrictions and guidelines that govern the US trading relationships with nonmarket economies