Polyethylene glycol octadecyl ether: Phase Change Properties & Comb-Like Polymer Synthesis

Polyoxyethylene (20) stearyl ether (Polyethylene glycol octadecyl ether) is a polyethylene glycolated lipid surfactant that can be used in the formation and stabilization studies of nanoparticles. PEG surfactant is useful to form micelles, drug delivery systems to enhance drug solubility and improve formulation and bioavailability. mPEG attached to C18 via amide bond or hydrolytic ester bond are available, please contact us.

Crystal structure and thermal property of polyethylene glycol octadecyl ether

Phase change material (PCM) is a kind of clean and reusable energy-storage material based on the solid–liquid or solid–solid phase change process. The research on phase change material has attracted increasingly attention since the 1970s . Organic phase change materials, i.e. paraffin, fatty alcohol, fatty acids, polyethylene glycol (PEG), aliphatic polyester, etc., are very important in energy-saving building construction, heat transfer media, thermo-regulated fiber, fabric and clothing, etc. Paraffin, fatty alcohol and fatty acids are highly mobile in the liquid phase. Polyethylene glycol alkyl ether [HO(CH2CH2O)nCmH2m+1, CmEn] is a widely used nonionic surfactant. The hydrophile–lipophile balance (HLB) changes with the number of repeat units (n) and the number of carbon in alkane (m). They can be fabricated by addition polymerization of 1-alkylic acid with ethylene oxide. To the best of our knowledge, there is a little information available about the crystal structure, crystallization, phase change property and thermal stable temperature of CmEn. Only the melting property of octaethylene glycol tetradecyl ether (C14E8) was investigated. The crystal structure, phase change property and thermal stable temperature of Polyethylene glycol octadecyl ether (n = 2, 10, 20 and 100) were investigated in this paper.[1]

The crystal structure, phase change property and thermal stable temperature of polyethylene glycol octadecyl ether with 2–100 repeat units were investigated. The crystal structure of C18En for n ≥ 20 is a monoclinic system. Polyethylene glycol octadecyl ether crystallizes perfectly at 0 °C. Tm, Tc, ΔHm and ΔHc of C18En (n = 2, 10, 20 and 100) decrease at first; and then increase with increasing the number of repeat units. Tmp and Tcp are in the range of 44.6–61.4 °C and 25.2–41.7 °C, respectively. The ΔHm and ΔHc are in the range of 107–183 J/g and 95–166 J/g, respectively. The melting and crystallizing behaviors of C18En (n = 2, 10, 20 and 100) are different from those of PEG-2000, n-octadecane and 1-octadecanol. The thermal stable temperature of C18En (n = 2, 10, 20 and 100), which is in the range of 221–360 °C, increases rapidly with increasing the number of repeat units. They approach to that of PEG-2000 as the number of repeat units is more than 10. C18En are a series of superior polymeric phase change materials.

Fabrication and properties of poly(polyethylene glycol octadecyl ether methacrylate)

Energy is the basis for human survival and development. The demand for energy is greatly increasing with the economic development as well as the social progress. Therefore, it has become a popular issue to search for new energy sources and improve energy efficiency.  In this study, the fabrication and properties of a new comb-like polymer-poly(polyethylene glycol octadecyl ether methacrylate) (poly(C18E2MMA) and its potential application as a polymeric phase change material were investigated. Polyethylene glycol octadecyl ether was melted in a four-necked flask. A predetermined amount of HQ (inhibitor) and p-TSA (catalyst) were added. MMA was gradually added by a constant pressure funnel, slowly heating to 120 °C with magnetic stirring, maintained 8 h. After the reaction, unreacted MMA and generated methanol were removed by rotary evaporation under reduced pressure. Then dissolved the product in CHCl3, and washed it with 4 wt% NaOH solution repeatedly until both oil and water layer did not change color, which indicates that p-TSA, hydroquinone and its oxides were removed completely. Follow on rotary evaporation under reduced pressure to remove CHCl3 and a small amount of water. A yellow product is obtained, and the yield is up to 70%.[2]

Polyethylene glycol octadecyl ether methacrylate (poly(C18E2MMA)) was synthesized successfully in the method of melting ester exchange. It is feasible to obtain the comb-like polymeric phase change material by free radical polymerization. The number average molecular weight and weight average molecular weight of poly(C18E2MMA) are 27,993 and 107,702 g.mol−1, respectively. The melting and crystallizing enthalpy of poly(C18E2MMA) are 73 and 81 J.g−1, respectively, which starts to melt at 41.1 °C, and crystallize at 35.4 °C. Poly(C18E2MMA) is thermal stable below 295 °C.

References

[1] Jie-yun Meng. (2013). Crystal structure and thermal property of polyethylene glycol octadecyl ether. Thermochimica Acta, 558, Pages 83-86.

[2] Jie-yun Meng. (2013). Fabrication and properties of poly(polyethylene glycol octadecyl ether methacrylate). Thermochimica Acta, 574, Pages 116-120.

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