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Utilization of renewable biomass to prepare phase change material (PCM) that can reversibly store renewable thermal energy is of great interest. Castor oil with functional hydroxyl groups is especially attractive for the preparation of polymeric materials. In this work, a novel castor oil-based polyurethane-acrylate oligomer (COPUA) was firstly synthesized through a two-step condensation reaction. Followed by in situ polymerization of COPUA in the presence of palmitic acid (PA), a novel biomass-based form-stable PCM was prepared, in which renewable PA serves as phase change functional ingredient and castor oil-based crosslinking network acts as encapsulation material. Tailoring the mass ratio of PA and COPUA provides the ultimate encapsulation ratio (70%) of PA in form-stable PCM. The chemical structure, crystalline property, thermal property of form-stable PCM were characterized using Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, differential scanning calorimetry and thermogravimetric. Those results demonstrate that the prepared form-stable PCM possesses that good thermal storage capacity with the phase change enthalpy reaches 141.2 J g−1. Accelerated thermal cycling test was also performed to illustrate the thermal reliability of form-stable PCM. [ABSTRACT FROM AUTHOR]

Three kinds of thermoplastic poly(urethane‐urea) PCMs were synthesized by two‐step condensation polymerization for thermal energy storage. Polyethylene glycol (PEG) was employed as the phase‐change functional chain, and three kinds of diamine compounds were individually adopted as chain extender. The chemical structure, crystalline properties, phase‐change behaviors, thermal stabilities, and reliabilities were studied by Fourier transform infrared spectroscopy, X‐ray diffraction, polarizing optical microscopy, and thermogravimetric, respectively. The crystalline structure of synthesized thermoplastic PCMs is identical to pure PEG, but the spherulite size decreases to some extent due to the confined crystalline region. The synthesized thermoplastic PCMs have proper phase‐change temperature with high phase‐change enthalpy of about 88 J/g. The synthesized thermoplastic PCMs are stable at their processing and working temperature with the onset degradation temperature higher than 250°C, and tensile strength reaches 20.59 MPa. Thus, the synthesized thermoplastic PCMs can be processed into desirable shape for the special applications in energy storage. [ABSTRACT FROM AUTHOR]

Abstract: Adipamide used as the curing agent of asphalt‐modified epoxy resin was synthesized by esterification and ammonolysis, and its chemical structure was confirmed by the Fourier transform infrared spectroscopy (FTIR), 1H and 13C nuclear magnetic resonance (1H NMR and 13C NMR) analysis. The thermal stability, Vicat softening temperature, tensile strength, and Shore D hardness of the cured asphalt‐modified epoxy resin were studied by thermogravimetric analysis (TG), Vicat softening tester, tensile tests, and Shore D plastic hardness tester, respectively. The surface morphology of epoxy resin tensile fracture was also observed by scanning electron microscopy (SEM). The Vicat softening temperature of cured epoxy resin decreased from 95 to 64°C with increasing modified asphalt (MA) contents from 0 wt.% to 25 wt.%. The maximum tensile strength of cured epoxy resin reached 45.4 MPa when MA content was 5 wt.% of the whole resin. The Shore D hardness slightly decreased from 86 D to 79 D as the MA was enhanced from 0 wt.% to 25 wt.%. TG results displayed that the thermostable temperature of cured epoxy resin was higher than 280°C. [ABSTRACT FROM AUTHOR]

It is a challenge to simultaneously retain high performance and green synthesis process of polyurethane (PU). Here, a PU was synthesized completely using ethanol as solvent based on the chain extender, hexanediamine (HMD), with higher reactivity towards isocyanate groups than ethanol. Chemical components in PU prepared by a green process (GPU) were characterized by Fourier Transform Infrared Spectroscopy (FTIR). Molecular weight and its distribution of GPU were characterized by Gel Permeation Chromatography (GPC). Mechanical properties and thermal-mechanical properties of GPU were characterized by Electronic Tensile Testing Machine and Dynamic Thermomechanical Analysis (DMA) separately. The glass transition temperature (Tg) and thermal stability of GPU were characterized by Differential Scanning Calorimeter (DSC) and Thermogravimetric Analysis (TGA). Results showed that this GPU presented superior mechanical properties of 61.4 MPa and low saturated water absorption of 6.6% compared with conventional solvent-based PU and waterborne PU whose synthesis process contained some toxic organic solvent. [ABSTRACT FROM AUTHOR]

A series of poly(urethane-urea-amide) thermoplastic elastomers ( PUUAs) based on polytetrahydrofuran (polytetramethylene glycol, PTMG), nylon-6 and 4,4′-diphenylmethane diisocyanate were synthesized through reactive processing. This method solved the incompatibility of nylon-6 and PTMG, and these model elastomers were used to gain insight into the structure-property relations of block polymers. The target products were solvent resistant, transparent and melting-processable. Fourier transform infrared spectroscopy, XRD, DSC, TEM, dynamic mechanical analysis, tensile testing and TGA were used to study the structure, crystallization, morphology, mechanical properties and thermostability of the PUUAs. The Fourier transform infrared results proved the successful preparation of PUUAs from nylon-6 and PTMG. TEM examination showed that all samples exhibit microphase separated morphology with the nylon-6 domain dispersed in the PTMG phase. The results of tensile testing indicated that the elastomers exhibit excellent mechanical properties with stress at break and strain at break exceeding 40 MPa and 600% respectively. The TGA results implied that the PUUAs can be fabricated by transitional processing at proper temperature without any thermodegradation. These favorable features were related to the microphase separated structure of the PUUAs. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

An in situ embed ionic liquid method is designed and employed in thermoplastic polyurethanes (PUs). Unlike the traditional physically incorporated antistatic polymers where conductive fillers do not firmly combined with the matrix. This permanently antistatic PUs are successfully synthesized by using a novel polyester diol bonded with ionic liquids (ILs), which are obtained by an esterification. The ILs and novel polyester polyol are successfully synthesized and subsequently characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectrum (1H NMR), respectively. The effects of ILs content, temperature, and relative humidity (RH) on the surface resistivity of PUs are studied by surface resistivity tests. It is found that the surface resistivity of PUs dramatically decreases with the increment of ILs and are insensitive to surrounding environment. The surface resistivity of PUs with 5.96 wt% ILs reaches 1010 Ω cm−2 order of magnitude. The crystalline properties, thermal decomposition behaviors and mechanical properties of synthesized PUs are investigated by X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and tensile test respectively. The crystallinity of PUs with ILs is lower than that of pure PUs. Moreover, we also investigate the effect of ILs on the surface morphology of the PUs. POLYM. ENG. SCI., 56:629-635, 2016. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

An alcohol-soluble acrylic resin used to improve the dispersity of modified silver nanoparticles (AgNPs) was successfully synthesized. The structure of acrylic resin was designated according to the elements and groups on the surface of modified AgNPs. The content of γ-(2,3-epoxypropoxy)propytrimethoxysilane (KH-560) and conductive filler, temperature, mechanical properties, anticorrosion, and so on were investigated in order to optimize the electrical conductivity and dispersion of modified AgNPs in coating. Surface chemical structure of modified AgNPs was characterized by X-ray photoelectron spectroscopy. Morphology of conductive coating was characterized by scanning electron microscopy. Groups in modified AgNPs and acrylic resin were characterized by Fourier transform infrared spectroscopy. And surface resistivity of conductive coating was characterized by digital multimeter techniques. The optimum surface resistivity of the acquired AgNPs conductive coating could be up to 0.01 ohm/sq, reaching the level of electromagnetic interference shielding. Moreover, the conductive coating possesses good property of anti-chemical and weather corrosion resistance. [ABSTRACT FROM AUTHOR]

In this study, a homologous series of calcium stearoyl lactylates (CSLs) with adjustable phase transition temperature were synthesized as solid–liquid phase change materials (PCMs) by esterification between stearic acid (SA) and lactic acid (LA), combining with the self‐esterification of LA, and neutralization with calcium hydroxide (Ca(OH)2). The chemical structures of CSLs were confirmed by Fourier transform infrared spectroscopy (FT‐IR) and 1H nuclear magnetic resonance spectrum (1H NMR). X‐ray diffraction (XRD) was applied to study the crystalline structure of solid–liquid PCMs. Differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA) were carried out to determine the phase change properties and thermal stability of prepared CSLs. Research results show that calcium ions (Ca2+) have positive effects on improving form stability of synthesized PCMs. The melting temperatures in the range of 40.45°C–25.47°C could be tailored by varying the molar ratio of SA to LA from 1:1 to 1:4. The thermal storage capabilities reach about 53% with the latent heat of fusion in the range of 84.5–55.50 J/g. The PCMs show acceptable thermal reliability and reusability after thermal cycles for 100 times. Suitable phase transition temperatures make CSLs potential for thermal comfort, and the mechanism of temperature regulation would provide reference for design of more PCMs used in different situations. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13136, 2019 [ABSTRACT FROM AUTHOR]