Dichloromethane swelling properties

Another important consideration was the choice of resin. The use of Hmb was developed using resins composed of polydimethylacrylamide polymerized within the pores of a solid, macroporous support, either Pepsyn or polyhipe, both are exemplified below. The use of Hmb involves the switching of solvents from DMF to dichloromethane the resins mentioned have excellent swelling properties in both solvents. However, some commercial polystyrene supports have given poor results because of the need to switch solvents, which can cause problems due to resin shrinkage. 1 ... 

The POEPOP resins are obtained by anionic polymerisation of monomers 3 and 4. The loading capacity can be controlled by the corresponding ratio of the monomers. Both POEPS and POEPOP resins show excellent swelling properties in solvents such as dichloromethane, DMF and water. 

In 1971, Sheppard proposed that peptide synthesis would proceed more efficiently if the polymeric support was designed to have solvation properties similar to those of the peptide product.This line of reasoning led to the development of polyamide resins.The most successful of this type of support is based on cross-linked poly(dimethylacrylamide) (Pep-syn). Polyamide resins swell up to 10 times their dry volume in dimethylformamide and even more in water. On the other hand, they swell much less in dichloromethane. The few comparative studies that have been carried out between polystyrene and polyamide resins indicate that both give very similar results in routine solid-phase peptide synthesis. 

The swelling of cellulose in the presence of moisture is a well known property of this material. Other protic and nonprotic solvents such as methanol, ethanol, acetonitrile, and acetone also have the capacity to swell microcrystalline cellulose. However, solvents such as benzene, toluene, or dichloromethane do not promote this effect. Therefore it is possible to control adsorption of probes on microcrystalline cellulose, either on the surface or entrapped within the natural polymer chains. After the removal of the solvent used for sample preparation, and for a swelling solvent, a chain-guest-chain interaction is promoted, replacing the previous chain-solvent-chain interaction. 

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