HPMC is one of our best-selling products, offering both affordability and high quality. It serves as a thickening and water-retention agent in construction materials. Shijiazhuang Cellulose Co., Ltd., a cellulose manufacturer based in China, is able to provide you with an ample and reliable supply.
Regarding the thermal gelation temperature of the cellulose ether HPMC: at temperatures above the gel point, water retention is high; conversely, at temperatures below this point, the water retention rate is lower.
Regarding the viscosity of the cellulose ether HPMC: as the viscosity of HPMC increases, the water retention rate also rises; however, once the viscosity reaches a certain level, the increase in water retention tends to level off.
Regarding the uniformity of the cellulose ether HPMC: if the HPMC reaction is uniform—meaning the methoxy and hydroxypropoxy groups are evenly distributed—the resulting water retention rate will be high.
The hydrophilic action and mechanism of Hydroxypropyl Methylcellulose (HPMC) are as follows: high-quality HPMC can disperse uniformly and effectively within cement mortars and gypsum-based products, encapsulating all solid particles and forming a wetting film around them. The moisture within the matrix is then released gradually over an extended period through the inorganic binder. This sustained hydration reaction of the cementing materials ensures the development of the material's bonding strength and compressive strength.
Therefore, during construction in hot summer conditions, it is essential to incorporate high-quality HPMC products into the mix according to the specific formulation to achieve the desired water retention effect. Failure to do so may result in insufficient hydration caused by excessive drying. This can lead to quality defects such as reduced strength, cracking, hollowing, and spalling, while also increasing the difficulty of the work for construction personnel.
As the ambient temperature decreases, the dosage of HPMC can be gradually reduced while still achieving the same level of water retention. Factors such as air temperature, substrate temperature, and wind pressure all influence the rate of moisture evaporation from cement mortars and gypsum-based products. Consequently, adding the exact same quantity of HPMC products during different seasons may yield varying water retention results. In concrete construction, the dosage of HPMC can be adjusted—increased or decreased—to regulate the water retention performance of the slurry.
The water retention capability of methylcellulose ethers at high temperatures serves as a crucial indicator for distinguishing the quality of these materials. Superior HPMC product series can effectively resolve water retention challenges encountered in high-temperature environments. During hot seasons—particularly in arid regions or when applying thin-layer materials to sun-exposed surfaces—high-quality HPMC is indispensable for enhancing the water retention of the slurry. High-quality HPMC is characterized by its exceptional uniformity; its methoxy and hydroxypropoxy groups are distributed evenly along the cellulose molecular chain, thereby enhancing the capacity of the hydroxyl groups and the oxygen atoms within the ether linkages to bond with water molecules and form hydrogen bonds. Free water is converted into bound water, thereby effectively controlling moisture evaporation caused by high temperatures and achieving high water retention.
The greater the amount of HPMC cellulose added, the higher the water retention rate and the more effective the water-retaining performance. Within the range of 4–6 kilograms, the water retention rate increases rapidly as the dosage increases; however, as the dosage is increased further, the upward trend in water retention rate begins to slow down.
