You are synthesizing a random copolymer from MMA (methyl methacrylate) and BMA (

Question

You are synthesizing a random copolymer from MMA (methyl methacrylate) and BMA (butyl methacrylate), with the target T_g of 40 degree C. It is known the homopolymers PMMA and PBMA have T_g of 105 and 20 degree C, respectively. What is the composition of the copolymer (i.e., the weight percentage of MMA and BMA units)? If you'd like to increase the T_g of the copolymer, which monomer do you need to add more? If a block copolymer (PMMA-b-PBMA) contains the same amount of MMA and BMA units, what kind of glass transition behavior would you expect to observe? Rank the T_g of PMMA, poly(methyl acrylate), and poly(butyl acrylate); explain how the ranking was made.

Explanation / Answer

1) To increase thrTg of the coploymer is butlyl acrylate ploymers(PBA) PBA is considerd as colorless transparent rubbery polymer with at ambient twmperature,thus it is coomenly used in co polymer systems to allevaite the brittleness of the final product.

2) If block co polymer (PMMA-b PBMA) contains the same amount of MMA and BMA unitsMMa is stable due to high thermal stability of tetrapbutylphosphonium cation. The thermal stability would increase.

3) The glass transition of PMMA is 398 K (1250C)The Tg Of other ploymers can vary ranging from approximately 360 k to 430 k (87 to 1570C).PMMA have high glass transition compression freezez PMMA in met stable state.PBMA has glass transition below thww room temperature the rubbery state PBMA demonstrates melt like behaviour.

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