Methylcellulose temperature effects

The properties of hydroxyethylcellulose are like those of methylcellulose except for the fact that there is little or no temperature effect on solubility. The degree of substitution required to impart water solubility will depend both upon the degree of polymerization of the cellulose and upon the uniformity of substitution. It is of interest... 

Velazquez de la Cruz G, Torres J, Martin-Polo M. Temperature effects on the moisture sorption isotherms for methylcellulose and ethylcellulose films. / Food Engin 2001 48 91—94. 

The stabilizing effects of methylcellulose and hydrated magnesium silicate were applied to calamine lotion. Sample 1 was the U.S.P. XV calamine lotion, and sample 2 the U.S.P. XV calamine lotion with 0.5% of methylcellulose. Sample 1 showed 50% separation, while sample 2 showed 12% separation after 24 hours at room temperature. 

Figure 2 illustrates the temperature dependence of the swelling degree as a function of precursor polymer type. Methylcellulose (MC), hydroxypropyl-methylcellulose, type E (HPMC-E) and hydroxypropylmethylcellulose, type K (HPMC-K) gels have comparable effective crosslink densities of about 2 x 10 5 mol/cm3 (as determined from uniaxial compression testing), while the crosslink density of the hydroxypropylcellulose (HPC) gel is about half this [52]. The transition temperature for each gel is within several degrees of the precursor polymer lower critical solution temperature (LCST), except for the MC gel, which has a transition temperature 9 °C higher than the LCST. The sharpness of the transition was about 3%/°C, except for the HPC gel transition, which was much sharper - about 8%/°C. 

The effects of diffusion control on the rate of radiation-initiated graft polymerization of cellulose have been studied theoretically. The effects of such variables as the initiator concentration, temperature, and monomer polymer ratio on the graft copolymerization of acrylamide and 0-methylcellulose have been investigated. The thermal properties and behaviour of graft copolymers of formaldehyde-cross-linked 0-cyanoethylcellulose and acrylates have been studied. Copolymerization of periodate-oxidized cellulose (aldehydocellulose) with glycidyl methacrylate in the presence of an enzyme e. peroxidase) afforded a means of immobilizing the enzyme without loss of activity. ... 

Fig. 9.14 Effect of RH on HPMCAS, PVP, HPMC, and hydroxypropyl methylcellulose phtha-late (HPMCP) Tg versus the RH to which samples were equilibrated at ambient temperature for representative polymers (a), and equilibrium water absorption versus RH measured at 25 °C (b)...

---