Hydration Heat Effect of Cement Pastes Modified with Hydroxypropyl Methyl Cellulose Ether and Expanded Perlite

Hydration heat effect of cement pastes and mechanism of hydroxypropyl methyl cellulose ether （HPMC） and expanded perlite in cement pastes were studied by means of hydration exothermic rate, hydration heat amount, FTIR and TG-DTG. The results show that HPMC can significantly delay the hydration induction period and acceleration period of cement pastes. As mixing amount increased, hydration induction period of cement pastes enlarged and accelerated period gradually went back. At the same time, the amount of hydration heat gradually decreased. Expanded perlite had worse delay effects and less change of hydration heat amount of cement pastes than HPMC. HPMC changed the structure of C-S-H during cement hydration. The more amount of HPMC, the more obvious effect. However, EXP had little influence on the structure of C-S-H. At the same age, the content of Ca （OH）2 in cement pastes gradually decreased as the mixing amount increase of HPMC and expanded perlite, and had better delay effect than that single-doped with HPMC or expanded perlite when HPMC and expanded nerlite were both dooed in cement pastes.

Influences of Carboxyl Methyl Celluloseon Performances of Mortar

Carboxyl methyl cellulose （CMC） was mixed into mortar to improve the waterretention performance of mortar, the quality of floated coat of aerated concrete became better. The consistency and compression strength of mortar with CMC were studied. The water absorption was studied with the method of filter paper. The micro mechanism was researched with X-ray diffraction and scanning electron microscopy（SEM）. The experimental results show the water-holding performance of mortar with CMC is largely improved and it is better when the mixed amount is about 1.5%; the compression strength had a descending trend with the increase of CMC; CMC reacted with calcium hydroxide（CH） into the deposition of calcium carboxyl methyl cellulose.

Regulating the Function of Nanocomposite Made from Hydroxypropyl Methyl Cellulose with Bacterial Cellulose Nanocrystal

Hydroxypropyl methyl cellulose(HPMC)-based hybrid nanocomposites reinforced with bacterial cellulose nanocrystals(BCNC) were prepared and characterized.The HPMC nanocomposites exhibited good thermal stability,with a thermogravimetric peak temperature of around 346℃.The addition of BCNC did not significantly affect the thermal degradation temperature or improve the transparency of HPMC nanocomposites.However,the addition of BCNC favorably affected the light scattering properties of the nanocomposites and enhanced mechanical properties such as tensile stress and Young's modulus from 65 MPa and 1.5 GPa up to 139 MPa and 3.2 GPa,respectively.The oxygen permeability of the HPMC nanocomposites also increased with increase in the amount of BCNC added.

Preparation and Swelling Kinetic Analysis of Poly (HPMC-co-AA-co-AM) Super Absorbent Resin

Super absorbent resin(SAR)is prepared by aqueous high temperature polymerization using hydroxypropyl methylcellulose(HPMC)as monomer backbone material,acrylic acid(AA)and acrylamide(AM)as the graft copolymer monomer,potassium persulfate(KPS)as the initiator to generate free radicals,and N,N`-methylenebisacrylamide(MBA)as cross-linking agent for cross-linking reaction.Simutaneously,the influence of individual factors on the water absorption is investigated,and these factors are mainly AA,AM,KPS,MBA,HPMC,and reaction temperature.The optimized conditions are obtained by the experiment repeating for several times.The water absorption multiplicity and salt absorption multiplicity under the conditions are 782.4 and 132.5 g/g,respectivity.Furthermore,the effects of different temperatures and salt concentrations on its water absorption,as well as the swelling kinetics of SAR are studied.It is indicated the water-absorbing swelling process is mainly caused by the difference in water osmotic pressure and Na+concentration inside and outside the cross-linked molecular structure of the resin,which is not only consistent with the quasi-secondary kinetic model,but also with the Fick diffusion model.

Preparation and Properties of Embeddable Ag/Ag Cl Gelling Reference Electrode for Rebars Corrosion Monitoring in Concrete

Reference electrodes are a key part for corrosion monitoring and measurement of rebars in concrete. A reference electrode that can be buried in concrete is fabricated by using Ag/Ag Cl electrode and methyl cellulose gelling electrolyte. The stability, repeatability and anti-polarization of the reference electrode are investigated; the influences of the inner electrolyte loss, exterior OH- contamination, and temperature on the potential of the reference electrode are also investigated in this paper. The results show that the reference electrode has good stability, repeatability, and antipolarization. The influences of inner electrolyte loss, exterior OH- contamination, and temperature on the potential of the reference electrode are minimal. Therefore, it can be used for corrosion monitoring and measurement of rebars in concrete.

Surface Modification of Nano-SiO_2 by Grafting PMMA/PBA

The surface of nano SiO 2 was modified by being encapsulated with hydroxy propyl methyl cellulose (HPMC), and then co grafted with acrylates. The grafting conditions, such as pH of the medium, and initiator concentration have been studied. The modified nano SiO 2 particles were characterized by TEM, DSC and FT IR spectra. TEM images show that the surface of the nano particles has been successfully modified by a thick layer of film like polymer in this way. The DSC results show that the decomposition temperature of modified nano particles of SiO 2 is 90 ℃ higher than that of grafted on polymer. According to the FT IR spectra, it is convinced that poly methyl methacrylate (PMMA) and poly acrylic butyl ester (PBA) were co grafted onto the surface of nano SiO 2.

Formulation and evaluation of anti-asthmatic drug montelukast in mucoadhesive buccal patches

Objective: To formulate and evaluate anti-asthmatic drug montelukast in mucoadhesive buccal patches. Methods:Buccal patches were formulated by using different hydrophilic polymers by solvent casting technique. Buccal patches were evaluated by seven physical appearances, in addition toin vitro drug release study. Results: All patches were uniform and translucent, and had smooth surface. In vitro release studies were conducted for montelukast buccal patches proved that release in the range of 75.26%-92.30% in 8 h. Emission of montelukast from all patches simulated zero order and diffusion mechanism. Finally it can be concluded that F3, F15 and F16 are the best formulation. Conclusions: The investigation concluded that patch of 5 mg of montelukast sodium were formulated by using sodium alginate with sodium carboxy methyl cellulose, hydroxy propyl methyl cellulose K100M with sodium carboxy methyl cellulose, and hydroxy propyl methyl cellulose K100M with sodium alginate (F3, F15 and F16 formulations) were the best formulations.