- 2074 Chaitra · 2 marks
Define borosilicate glass and thermoplastic
Short answer
Borosilicate glass contains silica and boron trioxide, giving it very low thermal expansion and high chemical resistance, used for laboratory glassware and ovenware. A thermoplastic softens when heated and hardens on cooling repeatedly because its polymer chains are linear, allowing remoulding; examples: PVC, polyethylene, polystyrene.
Define borosilicate glass and thermoplastic.
Borosilicate glass
Borosilicate glass is a glass containing silica (about 80%) and boron trioxide (about 13%), with some soda and alumina. It has a very low coefficient of thermal expansion, high chemical resistance and can withstand sudden temperature changes. Example: Pyrex. It is used for laboratory glassware, pipes, ovenware and lighting.
Thermoplastic
A thermoplastic is a plastic that softens on heating and hardens on cooling, and this can be repeated many times without chemical change because the polymer chains are linear and not cross-linked. They can be remoulded and recycled. Examples: PVC, polyethylene, polystyrene, acrylic (PMMA), nylon.
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