Synthesis and characterization of cellulose-g-polyoxyethylene (2) hexadecyl ether solid–solid phase change materials

Abstract

A series of novel solid-solid phase change materials, namely, cellulose-g-polyoxyethylene (2) hexadecyl ether (Cellulose-g-E 2 C 16 ) copolymers, were synthesized using toluene 2,4-diisocyanate (TDI) as a coupling reagent in the ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl). The optimum prepolymerization conditions were determined to be 25°C and 75 min without catalyst, and the optimum reaction conditions of the grafting step were 90°C, 6 h and 0.1 wt% dibutyltin dilaurate (DBTDL, weight percent of TDI). The successful grafting was confirmed by FTIR and 1 H-NMR. The properties of the Cellulose-g-E 2 C 16 copolymers were investigated by DSC, TG and XRD. It is shown that the heat storage ability and phase change temperature of Cellulose-g-E 2 C 16 copolymers depended on the degree of substitution. The crystalline type of the grafted E 2 C 16 was not affected by the cellulosic backbone. Compared with E 2 C 16 , Cellulose-g-E 2 C 16 copolymers showed better thermal stability. They are expected to be widely applied in the area of thermal energy storage.

Characterization of regenerated cellulose prepared from different pulp grades using a green solvent

“…contains more flexible and some long cellulosic fibre chains, which are stiffer compared to D.G.P, and B.G.P. 7,31 The DP of the cellulose polymer chains can be well correlated with the average fibre length of the samples, as depicted in Table 2. The arithmetic fibre length, as well as the mean fibre length, is comparatively higher for the sample with higher DP, i.e., T.G.P.…”

“…[26][27][28] The value of η generally defines the dimension and flexibility of individual polymer chains in a good solvent. 7 In a good solvent, an individual polymer coil is well solvated with an extended conformation, preventing the polymer from selfassociation and contraction. Thus, it has been proved to be an essential parameter for determining the solution properties of polymeric macromolecules in different solvents.…”

“…Generally, the cellulose solubility test is performed to understand the dissolution properties in any solvent. 7 In our experiment, 0.2 g of each pulp sample was dispersed in a total of 20 g of the solvent. After the freeze thawing process, the undissolved cellulose residue was isolated by centrifugation, washed until free of NaOH/urea/thiourea and finally dried in an oven for calculating the cellulose mass.…”

“…From an economic point of view, this system has still not taken the place of the viscous technique of fabricating RC fibres. 7 Other solvents include ionic liquids, N,Ndimethylacetamide, lithium chloride/dimethylacetamide. 6 The constraints observed by different scientists while studying the dissolution of cellulose in the solutions above make them reconsider the dissolution of cellulose in a more economic and a greener way.…”

“…[8][9][10][11][12][13][14] They have observed that the solubility percentage of cellulose greatly increased with the addition of additives, such as urea or thiourea, to NaOH/water binary systems, compared to the dissolution in only NaOH/water systems. 7,15,16 They concluded that additives, alkali and water form intermediate complexes through the formation of hydrogen bonds with cellulosic macromolecules, with the destruction of the interand intra-hydrogen bonds existing in native cellulose and result in faster and more dynamic self-assembly of the cellulose molecules. These solutions are quite stable at low to ambient temperatures and maximum solubility depends on the source, degree of polymerization (DP) and the weight percentage of the additives in the alkaline medium.…”