HPC is a water soluble derivatives of cellulose biopolymer, so the polymerization reaction can be conducted in aqueous solution. A cross-linked polymer can be synthesized through crosslinking of HPC with epichlorohydrin and ammonia in presence of sodium hydroxide as per the procedure described by the following reference:

Yan, L., Shuai, Q., Gong, X., Gu, Q. and Yu, H. (2009), Synthesis of Microporous Cationic Hydrogel of Hydroxypropyl Cellulose (HPC) and its Application on Anionic Dye Removal. Clean Soil Air Water, 37: 392–398. doi: 10.1002/clen.200900006

Sir thanks for the answer. I used Divinylsulfone to crosslink HPC, but was not able to get a hydrogel. I will surely look into the paper that you have mentioned. 

I have published a well-cited paper on cross linking HPC with DVS to make elastic gels:

CONTROLLING THE SWELLING CHARACTERISTICS OF TEMPERATURE-SENSITIVE CELLULOSE ETHER HYDROGELS

By: HARSH, DC; GEHRKE, SH

JOURNAL OF CONTROLLED RELEASE Volume: 17 Issue: 2 Pages: 175-185 Published: OCT 1991

Dear Sir, 

I am referring the paper you have quoted and other papers published by you . Thanks  a lot sir.

You're welcome. Over the years we have found DVS crosslinks various polysaccharides quite well above 10 wt% or so polymer.  The polymer needs to be stable in basic pH required for the reaction (we usually wait 24 hr for the cross linking reaction). DVS does degrade over time so we find reproducibility of gel properties depends on using properly stored DVS (refrigerated, water-free). DVS is quite toxic so we always use it in the hood with gloves, but once well-leached the gels are safe to handle.  We also find that at high DVS concentrations there will be free VS groups on the gel which can have undesirable side reactions with other molecules, but these can be capped off by post gelation reaction with ethylene glycol. Good luck!

Thanks a lot for the information sir. I am using DVS as a crosslinker and it is indeed properly stored.I have even maintained the pH of the solution. I have done the crosslinking reaction by the modified TIPS method but only for 12 hours and did not get any hydrogel. I will repeat the experiment with the duration of 24 hours as suggested by you. I have used the crosslinker to polymer ratio of 0.141 g/g. Should the DVS taken be 10wt% or above with respect to polymer wt%? 

Thanks again for your time.