hpmc for gypsum
1. What are the main uses of hydroxypropyl methylcellulose (HPMC)?
HPMC is widely used in construction materials, coatings, synthetic resins, ceramics, pharmaceuticals, food, textile, agriculture, cosmetics, tobacco and other industries. HPMC can be divided into construction grade, food grade and pharmaceutical grade according to its usage. Currently, most Chinese domestic production is at the construction level. At the construction level, putty powder is used in large quantities, about 90% for putty powder and the other for cement mortar and tile adhesive
In recent studies we have investigated the water retention behavior of hydroxyethyl cellulose (HEC) and carboxymethyl hydroxyethyl cellulose (CMHEC) in oil well cement, respectively. We found that the working mechanism of HEC relies on a dual effect, namely its enormous intramolecular water sorption (binding) capacity and a concentration dependent formation of hydrocolloidal associated polymer networks [23]. Contrary to this, the working mechanism of CMHEC changes with dosage. At low dosages (up to ~ 0.3% by weight of cement), adsorption presents the predominant mode of action, whereas above a certain threshold concentration (the “overlapping” concentration), formation of associated polymer networks is responsible for its effectiveness [24].