Hydroxypropyl methylcellulose (HPMC) water retention properties

Hydroxypropyl methyl cellulose (HPMC) plays a crucial role in the field of building materials, especially in cement and 

gypsum-based dry-mixed products. One of its main functions is water retention, which can significantly improve the 

cohesiveness and anti-sagging property of mortar.

Environmental factors have a significant impact on the evaporation rate of water in cement or gypsum-based mortar, 

such as air temperature, humidity, and air flow rate. These factors can cause the same amount of HPMC products to 

exhibit different water retention efficiencies in different seasons. Therefore, during the actual construction process, 

the amount of HPMC added can be flexibly adjusted according to environmental conditions to optimize the water 

retention performance of the mortar. In a high-temperature environment, the water retention performance of HPMC 

is a key indicator for measuring its quality. High-quality HPMC products can effectively solve the water retention 

problem in a high-temperature environment. During the construction of thin layers in hot and dry areas and on the 

sunny side, good water retention performance can be provided for the mortar. High-quality HPMC has good uniformity. 

Its methoxy and hydroxypropoxy groups are evenly distributed along the cellulose molecular chain, which can enhance 

the ability of the oxygen atoms on the hydroxyl and ether bonds to associate with water molecules to form hydrogen 

bonds, promoting the conversion of free water into bound water, thereby effectively suppressing the evaporation of water 

caused by high temperature and achieving an efficient water retention effect.

High-quality HPMC can be evenly and effectively dispersed in cement mortar and gypsum-based mortar, wrapping all solid 

particles and forming a wet film layer. This film layer can gradually release the water in the base layer over a long period of 

time, ensuring that the condensed substances can smoothly undergo a hydration reaction, thereby guaranteeing the bonding 

strength and compressive strength of the materials. Therefore, during the construction in a hot summer, in order to achieve 

an ideal water retention effect, high-quality HPMC products must be added in sufficient quantities according to the formula. 

Otherwise, the mortar may experience problems such as insufficient hydration, reduced strength, cracking, hollowing, and falling 

off due to excessive drying, and it will also bring greater difficulties to the construction operation. As the temperature decreases, 

appropriately reducing the amount of HPMC added can also maintain a good water retention effect.

The water retention performance of HPMC is affected by multiple factors in combination:

Uniformity

The methoxy and hydroxypropoxy groups of HPMC obtained through a homogeneous reaction are more evenly 

distributed, and it has a higher water retention rate.

Gelation Temperature

When the gelation temperature of HPMC is higher, its water retention rate will also increase correspondingly; conversely, 

the water retention rate is lower.

Viscosity

Generally, the viscosity of HPMC has a positive correlation with the water retention rate. As the viscosity increases, the water 

retention rate also gradually increases. When the viscosity reaches a certain specific value, the growth rate of the water retention 

rate will gradually tend to flatten.

Particle Size

HPMC with a larger particle size has a faster dissolution rate, and its water retention performance can be exerted more quickly.

Addition amount

The greater the addition amount of HPMC, the higher its water retention rate and the better the water retention effect. 

In the addition amount range of 0.25-0.6%, the water retention rate will rise rapidly with the increase of the addition amount; 

when the addition amount increases further, the growth trend of the water retention rate will gradually tend to be flat.

In conclusion, understanding the factors affecting the water retention performance of HPMC is of great guiding significance 

for the rational use of HPMC in different construction environments and ensuring the quality and performance of building materials.

Name: Cecilia.Wang

E-Mail:cecilia.wang@jtdf-rdp.com

Mobile:+86 190 3451 3486（Whatsapp）