Question

........All these processes belong to chemical modification of polymers except.1 Synthesis of Nylon 66 Graft of methyl methacrylate onto cellulose acetate Transformation of cellulose into cellulose nitrate Displacement of labile sites of PVC by stabilizer's moities stun له بمنع الانتقال إلى السؤال الثاني إجراء تعبيرات على ها

Answer 1

CORRECT OPTION: 1

The first one is actual synthesis of Nylon 66;

But the other options are modifications of polymers already synthesised either naturally or synthetically.

Synthesis of Nylon 66

Nylon 66 can be prepared from hexamethylenediamine and adipic acid. It is a polycondensation reaction.

OPTION: 2

Cellulose is a polymer of a- D glucose units.  It can be converted to (chemically modified) cellulose nitrate in presence of nitric acid.

OPTION: 3

PVC is a widely used commercial plastic material. It is thermally unstable at processing temperature and hence chemically modified by the use of thermal stabilizers. Widely used thermal stabilizers are toxic heavy metal and organo-tin compounds.

OPTION: 4

Cellulose acetate is a commercially available cellulose derivative. Graft copolymers can be prepared by (chemically modified) (a) graft polymerization of monomers initiated by the active sites on the polymer backbone and (b) coupling of two reactive polymers. Graft polymerization proceeds by free radical, anionic, cationic, ring opening etc. depending on the nature of the active sites on the backbone and the type of monomer. Depending on the reaction medium, grafting reactions may be heterogeneous and homogeneous. In heterogeneous graft polymerization, synthetic polymers are grafted onto cellulose and cellulose acetate.