Tham khảo sách 'chemistry part 38, julia burdge,2e (2009)', khoa học tự nhiên, hoá học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 942 CHAPTER 25 Modern Materials amino group of one amino acid and the carboxy group of another. See Figure . One water molecule is produced as each new C N bond is formed. The C N bond formed between an amino group and a carboxy group is called an amide bond because RCONR R is the general form of an amide Section . Table . Polymers in which the monomers are connected by amide linkages are called polyamides. The amide bond between amino acids is more specifically called a peptide bond and proteins are routinely referred to as polypeptides. Although polypeptides can form from a single amino acid . polyvaline most proteins in organisms consist of chains of different amino acids. As a result most proteins are random copolymers Table . Nylon 6 6 is a synthetic condensation polymer formed from hexamethylenediamine a molecule with two amino groups and adipic acid which has two carboxy groups. Water is the small molecule eliminated in this condensation reaction. hh2n- ch2 -nh2 oh-c- ch2 -c-oh - -nh- ch2 -nh- c CH2kc 2zîH2O Both hexamethylenediamine and adipic acid contain six carbon atoms which is why the resulting polymer is called nylon 6 6. Like proteins nylon 6 6 contains amide linkages between monomers so nylon 6 6 is a polyamide too. Also like proteins nylon 6 6 is a copolymer although nylon 6 6 is an alternating copolymer Table not a random copolymer. Dacron is the trade name for the condensation copolymer formed from ethylene glycol a diol a molecule with two alcohol groups and zrzra-terephthalic acid a diacid a molecule with two carboxy groups . The condensation reaction removes the hydrogen atom from the alcohol on one monomer and the OH group from the carboxy group on a second monomer producing water. 2 l IoO Figure Structure of DNA. The bond that forms between each ethylene glycol monomer and each jrzra-terephthalic acid monomer is called an ester linkage because RCOOR is the general form of an ester K Section . Table .
