Acrylonitrile-butadiene-styrene (ABS), is a thermoplastic polymer used in cars, appliances, toys (including Legos) and as an âinkâ in 3D printers. It is known for its strength, toughness and resistance to distortion from heat. ABS is a terpolymer made up of the three monomer units shown below (Figure 8.2). The structure of the polymer is a chain of butadiene with acrylonitrile and styrene branching off the chain. Answer the questions below.
a) If the number averaged molecular weight of ABS is 43,000 g/mol, and the fraction of butadiene repeat units in the chain is 20%, fraction of styrene is 40%, what is the degree of polymerization of the ABS (10 pts)?
b) For the ABS composition given up above, what is the wt% N (5 pts)?
c) What is the covalent structure (sp3 or sp2) of the 1st and then the 2nd carbon atom in the butadiene repeat unit? Can the polymer twist about the bond between the first and second atom? Can the polymer twist about the bond between the second and third atom (8 pts)?
d) Is the majority of the ABS polymer going to be crystalline or amorphous? Briefly explain (4 pts).
H H H H H H C C C C Butadiene Styrene CAH 16 8 8 Figure 8.2. Repeat units making up ABS polymer. H H C-C Acrylonitrile C3H3N
