OPHTHALMIC NANOPARTICLES DRUG DELIVERY SYSTEMS (Ezine Ready)
Other names: Methyl Methacrylate resin PHYSICAL AND MECHANICAL PROPERTIES General physical properties PMMA is a glassy polymer with an amorphous structure. It has a density of 1.19 g/cm3 and has very low water absorption. The refractive index ranges from 1.49 to 1.51 depending on the type. Mechanical properties Thermal properties Parts made of PMMA have high mechanical strength and good dimensional stability. PMMA is one of the hardest thermoplastics and is also highly scratch resistant. THERMAL, ELECTRICAL AND OPTICAL PROPERTIES Heat-stabilized types can withstand temperatures of up to 100oC. PMMA can withstand temperatures as low as - 70oC. Resistance to temperature changes is very good. Glass transition temperature of PMMA is in the range of 100-1200C. Fire behavior PMMA ignites very quickly. It burns with a blue glow, even outside the flame, and crackles with white spurts. · Electrical properties PMMA has good insulating properties, a high dielectric strength and high tracking resistance. The relatively high surface resistance, however, encourages electrostatic charges on the surface of moulded parts; this can be largely overcome by the use of antistatic agents. Optical properties PMMA is naturally transparent and colourless. The transmission for visible light is 92%. The refractive index is 1.492 for PMMA. There are types that transmit UV rays, and types that absorb it almost completely, as a result of which sensitive dyes on painted surfaces behind are protected from fading. · Chemical Resistance Properties PMMA is resistant to aliphatic hydrocarbons, cycloaliphatic compounds, fats and oils, and also to dilute acids at temperatures of up to 60oC.Pages: 1 2 3 4 5 6 7 8 9 10 [11] 12 13 14
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01.02.2010
Banking Solutions for Customer ConvenienceBanking Solutions for Customer ConvenienceAuthor: bankbarsBanking has evolved with time. The entire infrastructure and concept of traditional piled files and documents has given away to a much more sophisticated and sleek outlook. Moreover with technology growing with a rapid pace the time consuming factor has been replaced with doorstep banking methods which permits you to carry on with your banking 24/7 without having to pay the bank any visit. Money orders and transfers have taken a backseat for Online Money transfers, Card and mobile banking. When Banking started of for Independent India, you had Nationalized and regional banks handling the country’s finances. |
What is the Gold Krugerrand Price Today?The 1904 double eagle is an offering that is a considerably popular coin and impressively accessible on the gold market. The coin itself varies in terms of condition and the 1904 double eagle coin’s condition and appearance play a heavy roll in its value. A 1904 double eagle that is in mint condition might cost between 1200 dollars and 1700 dollars, depending upon the price of gold and the seller. If the 1904 double eagle coin is in circulated condition, you can anticipate that the coin will There are certain things you need to look for when you are buying a double eagle gold coin. You will want to consider the condition of the double eagle gold coin, whether you are opting for the liberty double eagle gold coins, the St. Gauden double eagle gold coin, or the newer double eagle gold coins crafted after the year 1986. |