Question

Propose a method for the synthesis of a block copolymer of PS-b-PMMA by coupling of telechelic PS and PMMA, synthesized by living polymerization methods. Write down the reaction scheme. How would you know if you had a block copolymer of PS-b-PMMA or a physical mixture of homopolymers of PS and PMMA?

Answer 1

Step 1: preparation Ps-b-PMMA

Sample preparation PS-b-PMMA : 1. Heated to 180 °C for 10 minutes and pressed under 1000 lb load. 2. Decreased to room temperature by keeping 300 lb load. Blends of PS /PMMA: 1. Heated to 180 °C for 30 minutes and pressed under 600 lb load test for 5 minutes. 2. Decreased to room temperature by keeping 600 lb pressure. After the hot pressing processes, samples were all polished and sputtered by Ag electrodes.

Dielectric measurement using Broad Band NOVOCONTROL spectroscopy with automatic temperature control from -40 °C to 150 °C and frequency range from 0.01 Hz to 1 MHz.

Step 2: using anyone of this phisical mechanism to polymerise

Physical Mechanisms

Conductivity term: The contribution of free charge carriers

α-relaxation process: Attributed to long chain segmental motion within the main polymer chain

β-relaxation process: Primary localized motion of side segments