CM8001

Styrofoam has air pocket. When styrofoam is dissolved, air trapped in pocket are released and the reformed solid does not have air pocket. Hence,reformed solid is much denser as polymer are closer to one another

A) it does not have high resistance to being cut. This may increase the chance of infectio in patient during the surgery. HDPE is similar to LDPE but it is more rigid,tougher and slightly dense.

B) liner HDPE has lesser branches compared to branched LDPE. Hence ,HDPE is more rigid and higher resistance to being cut.

No. Paper is made up of cellulose and cellulose is make up of glucose molecule. Glucose monomer in cellulose are linked by beta linkage which make the cellulose packed into straight chain of polymer. This lead to formation of stronger interaction between molecule of polymer . Thus,giving paper a high tensil strength and rigidity whereas plastic is made up of LDPE which has less intermolecular forces of attraction due to it branched chains. Therefore,it has low tensil strength and can be easily stretch.

A) biodegradable, flexible ,small, non-toxic

B) PMMA is excellent optical properties,light weight ,shatter-resistance alternative to glass for many application. But it is impermeable to oxygen and other gases and cornea need significant supply of oxygen to stay healthy . Hydrogel can retain a lot of water to prevent dying out user eye.

C) Hard contact Len made of plastic called polymethyl methacrylate (PMMA) , also called acrylic or acrylic glass. Since oxygen cannot pass through PMMA contact len, it will cause discomfort that make wearing the lens impossible. Soft contact len made of pliable hydrophilic plastic called hydrogel which absorb significant amount of water to keep the lens soft and supple. The water content allow oxygen to pass through the len and keep cornea healthy.