Which of the following are example of synthetic rubber?
(a) Polychloroprene
(b) Polyacrylonitrile
(c) Buna-N
(d) cis-polyisoprene
Which of the following is not a semisynthetic polymer?
(a) cis-polyisoprene
(b) Cellulose nitrate
(c) Cellulose acetate
(d) Vulcanised rubber
Trans-form of polyisoprene is