Hydroxypropyl Cellulose Lab Report

INTRODUCTION

HPC is non ionic semisynthetic polymer.

Hydroxypropyl cellulose is also commonly known as hydroxypropyl methylcellulose (HPMC) or hypromellose which is a coating agent and film-former and used as an inactive ingredient in the pharmaceutical industry. It has also been used as a rate-controlling polymer for sustained-release dose forms in pharmaceutical industry.

CHEMISTRY

HPC is an ether of cellulose. In HPC some of the hydroxyl groups in the repeating glucose units have been hydroxypropylated which forms -OCH2CH(OH)CH3 groups using propylene oxide. The average number of substituted hydroxyl groups per glucose unit is referred to as the degree of substitution (DS).

In some cases hydroxypropyl group when added contains a hydroxyl group, this can also be etherified during preparation of HPC. In such case the number of moles of

CHEMISTRY Hypromellose is solid, slightly off-white to beige powder in appearance and may be formed into granules. HPMC compound forms colloids when dissolved in water. It isnon-toxic and is combustible and can react vigorously with oxidising agents.

Hypromellose in an aqueous exhibits a thermal gelation property.

Thermal gelatin property is a solution when heats up to a critical temperature, it congeals into a non-flowable but semi-flexible mass. Whereas this critical (congealing) temperature is inversely related to both the solution concentration of HPMC and the concentration of the methoxy group within the HPMC molecule ( higher the concentration of the methoxy group, the lower the critical temperature. The inflexibility/viscosity of the resulting mass, is directly related to the concentration of the methoxy group (so higher the concentration, the more viscous or less flexible the resulting mass is).

USES

The application for HPMC are as follows:-

Tile adhesives

Cement