Example 3
Synthesis of Aromatic Linked Siloxane Based Triblock Copolymer Pre-Soft-Segment:
To a 100 ml separable flask fitted with a mechanical stirrer, 15 g of hydroxy terminated polydimethyl siloxane (DMS-S14 from Gelest Inc.) was added along with 5.36 g of di-chloro p-xylene (from Sigma) and 0.0089 g of Copper(II) acetylacetonate (Cu(Acac)2 from Sigma). The reaction mixture was refluxed at 110° C. for 5 hrs. At this point, 19.77 g of hydroxy terminated poly(propylene glycol) (from Sigma) was added dropwise and the reaction mixture was then refluxed for another 15 hr. The progress of reaction was followed by 1H-NMR and the final molecular weight, determined by gel permeation chromatography (GPC), was 3000 g/mol.
H-NMR analysis; Solvent used for 1H-NMR analysis is CDCl3.
Aromatic H=7.25-7.45 ppm, —CH2=4.5-4.6 ppm, —CH3 (of PPO)=1-1.4 ppm, —CH2 (of PPO)=3.2-3.8 ppm, —OH (of PPO)=3.8-4 ppm, —CH3(silanol)=0.5-0.8 ppm.