Relationship Between Structure And Thermoresponsibility Of2-hydroxy-3-alkoxypropyl Polysaccharides Ethers

Different polysaccharides (2-hydroxyethylcelluose, dextran, hylon V, waxy maize starch, degraded waxy maize starch and2-hydroxyethylstarch) ethers were synthesized by using ethyl glycidyl ether (EGE), propyl glycidyl ether (PGE), iso-propyl glycidyl ether (i-PGE), t-butyl glycidyl ether (t-BGE), iso-butyl glycidyl ether (i-BGE), butyl glycidyl ether (BGE),3-butoxyethyl glycidyl ether (BEGE),3-(2-butoxyethoxy)ethyl glycidyl ether (BE2GE) and pentyl glycidyl ether (PeGE) as hydrophobic reagent, solvent’used water and catalyst was sodium hydroxid. H-NMR was used for characterization of polysaccharides ethers and calculation of their mole substitution (MS). In addition, thermoresponsibility, self-assembly behaviors and thermo-reduced aggregation behaviors of polysaccharides ethers were affected by changing the mole ratio of etherifying agents to anhydroglucose unit (AGU) in polysaccharides and the alkyl and oligo(ethylene glycol) spacers’length of etherifying agents. Expecially, In order to explore the effects of polysaccharides’molecular weight and branched contents on thermoresponsibilities of polysaccharides ethers, the water-solubilities and thermoresponsibilities of polysaccharides ethers, which were synthesized by reacting2-hydroxyethylcelluose, dextran, hylori V, waxy maize starch, degraded waxy maize starch and2-hydroxyethylstarch with BEmGE, were investigated.2-hydroxy-3-alkoxypropyl hydroxyethyl starch ethers (alkyl-HS) were synthesized by reacting2-hydroxyethyl starch with different alkyl (C2-C5) glycidyl ethers and using water as solvent, sodium hydroxid as a catalyst. The LCSTs could be tuned in the range of16.0℃～65.9℃by altering alkyl and MS of etherifying agents. Their critical micelle concentrations also could be changed from5mg/L to610mg/L by altering alkyl and MS of etherifying agents. Both the increase of concentration of NaCl and alkyl-HS could decrease their LCSTs. The micelle self-assemby behaviors of thermoresponsive alkyl-HS were investigated through using fluorescence specture and dynamic light scattering (DLS) measurment.2-hydroxy-3-(2-butoxy(ethoxy)m)propyl degraded waxy maize starch ethers (BEmS) were synthesized by reacting degraded waxy maize starch with BEmGE (m=0,1,2) and using water as solvent, sodium hydroxid as a catalyst. The LCSTs could be tuned in the range of17.5℃～55.℃by altering oligo(ethylene glycol) spacers’length and MS of etherifying agents. Their critical micelle concentrations also could be changed from3mg/L to278mg/L by altering oligo(ethylene glycol) spacers’length and MS of etherifying agents. For similar MS of BEmS, their LCSTs, cmcs and aggregation sizes upon LCST could arise with increase of oligo(ethylene glycol) spacers’ length. Both the increase of concentration of NaCl and BEmS could decrease their LCSTs. The micelle self-assemby behaviors of thermoresponsive BEmS were investigated through using fluorescence specture and dynamic light scattering (DLS) measurment.