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Isophorone diisocyanate-loaded microcapsules were synthesized with controllable size for self-healing of structural polymer materials. The obtained microcapsules showed good compatibility with polymer resins, e.g., one-component epoxy and multi-component polyurethane/water glass structural materials. During the processing of composite self-healing materials, the highly cross-linked composite capsule wall ensured the integrity of microcapsules and prevented the leakage and degradation of reactive liquid isocyanates effectively. A relatively larger amount of self-healing agent could be released to the local cracks with the increasing size and content of microcapsules in polymer matrix which improved the self-healing efficiency of the composites. Based on the microcapsules with a diameter of ~96 μm, the healing efficiency of epoxy composites containing 15 wt% of capsules and polyurethane/water glass composites containing 20 wt% of capsules could reach to 105 and 101% recovery of fracture toughness, respectively. The crack-healing effect was further verified by scanning electron microscopy. Meanwhile, a possible self-healing mechanism of microcapsules to the cracks of composite polymer materials was proposed. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A series of CO 2 derived amino-alcohol compounds were synthesized. • Structures of amino-alcohol compounds influenced the properties of adhesives. • PU adhesives from the synthesized amino-alcohol compounds showed excellent adhesion properties. • CO 2 derived adhesives showed other considerable properties. Abstract A series of novel amino-alcohol curing agents for PU adhesives were synthesized from CO 2 , glycidyl ether and diamine through carbonation and amination reactions. By physically evaluating the compounds through FT-IR and 1H NMR spectroscopy and mechanically analyzing the adhesives through T-peel strength tests, the raw materials have successfully been transformed into curing agents and the curing agents were found to endow the adhesives with specific structures and unique properties. For PVC bonding, compared to the traditional curing agents HDA and HDO, the T-peel strength and medium resistance from the novel amino-alcohol compounds improved. Further analysis revealed distinction in mechanical properties for different curing agents, the trifunctional curing agent exhibited the largest tensile strength and hardness. Moreover, thermal analysis of the adhesives demonstrated the considerable thermal stability to those prepared from HDA and HDO. [ABSTRACT FROM AUTHOR]

The performances of hybrid non‐isocyanate polyurethane (NIPU) materials were improved by using promising approaches. For the ring‐opening reaction of cyclic carbonate with excess amine, methanol was selected as solvent to increase the molar mass of NH2‐terminated NIPU pre‐polymer but also caused the formation of urea as a result of eliminating hydrogen bonding between NIPU chains. Meanwhile, another approach was carried out to reduce the content of urea by altering the introduction mode of reactants, along with further increasing the molar mass of the NIPU pre‐polymer. The final hybrid materials were prepared by adding bisphenol‐A diglycidyl ether into the pre‐polymer. The results indicated that the introduction of methanol and the change of the introduction mode of reactants could improve the performance of the hybrid materials. The hybrid material derived from the forward method has optimal performance with a tensile strength of 10.8 MPa, elongation at break of 167%, a glass transition temperature of 49.1 °C and a crosslinking density of 450 mol m−3 as well as presentable thermodynamic stability, ascribed to the high molar mass of the NIPU pre‐polymer, the low urea content and the dense crosslinking network. © 2018 Society of Chemical Industry The effect of hydrogen bonding and introduction mode of reactants on modifying performances of hybrid non‐isocyanate polyurethane was investigated. [ABSTRACT FROM AUTHOR]

In this work, CO 2 was chemically fixed by reacting with 1, 4-butanediol diglycidyl ether in the presence of a basic polystyrene resin catalyst. Under the 100% conversion of 1, 4-butanediol diglycidyl ether, five-membered cyclocarbonate with a selectivity of 98.5% was obtained. The cyclocarbonate was then reacted with an excess of 1, 2-ethylenediamine and the product was characterized by Fourier transform infrared spectrometer and nuclear magnetic resonance spectrometer. The results confirmed the successful synthesis of NH 2 terminated product with a selectivity of 98.9%, accompanied by the formation of hydroxyls on β-C to the carbonyl groups, which can be regarded as a new amino-alcohol. Further, the obtained amino-alcohol was applied for the preparation of polyurethane urea as chain extender in a prepolymer way. Since the reactivity of isocyanate with NH 2 is much faster than that with OH, the OH groups can be maintained in the system and hence strengthen the hydrogen bonding in polyurethane urea, which endows the materials with some unique properties. Comparing with the polyurethanes yielded from 1, 6-hexanediamine and 1, 6-hexanediol, polyurethane urea synthesized from the new amino-alcohol possessed better water/solvents resistance, considerable mechanical and thermal properties. [ABSTRACT FROM AUTHOR]

In this study, silane coupling agent 3-chloropropyltrimethoxysilane (CTS) was used for improving the distribution of water glass (WG) in the polyurethane (PU) matrix and increasing the crosslinking density of PU/WG grouting materials. The optimum dosage of CTS and the pretreatment time of WG were investigated. The effect of CTS on the surface property of WG and the fracture morphology of the PU/WG composites was studied by contact angle measurement and scanning electron microscopy, respectively. The effect of CTS on the mechanical properties of PU/WG grouting materials was systematically studied by compression test, fracture mechanical test, flexural test and dynamic mechanical analysis. The introduction of CTS in the PU/WG grouting materials improved the surface property of WG, the homogeneous distribution of polysilicate particles in PU matrix, the compressive property of PU/WG composites by 11.65–40.65%, the fracture toughness by 9.68%, the fracture energy by 21.33%, the flexural strength by 6.60%, the flexural modulus by 15.85%, and the dynamic mechanical properties of the composites. A possible mechanism of the functions of CTS in the PU/WG grouting materials was proposed. [ABSTRACT FROM AUTHOR]

A combined process for surface silanization of carbon fibers (CFs) was developed to improve the interfacial adhesion of carbon fiber reinforced polyurethane (PU) composites. The effect of each step of surface modification on the properties of CFs and the resulting CF/PU composites was investigated systematically. The change of surface composition of CFs was investigated by X-ray photoelectron spectroscopy. The morphologies of modified-CFs as well as the fracture surfaces of CF/PU composites were characterized by scanning electron microscopy. Silane molecules were grafted successfully on the surface of CFs as a uniform polysiloxane coating, which improved the tensile strength of CFs by 12.4%, the interfacial shear strength between CFs and PU by 47.88%, and the tensile strength of the resulting CF/PU composites by 18.3%. [ABSTRACT FROM AUTHOR]

Carbonated soybean oil (CSBO) is a precursor of nonisocyanate polyurethanes (NIPUs). So far, the ruling catalysts for CSBO synthesis through the coupling of epoxidized soybean oil (ESBO) with CO2 are homogeneous ones. In this work, a heterogeneous catalyst, 5 wt % H3PW12O40 (PW)/ZrO2 was investigated for the coupling reaction and proved quite efficient. However, the catalyst showed poor reusability due to the difficult elimination of bulky by-products retained in the spent catalyst. To remedy this deficiency, the 5 wt % PW/ZrO2 was modified with 0.3% Pt. It is found that Pt addition markedly improved the reusability of the 5 wt % PW/ZrO2 without loss in carbonation activity. An ESBO conversion of 78.3% was obtained at the end of third recycle, indicating that Pt species incorporated could promote the removal of the by-products and hence protect the active centres of 5 wt %PW/ZrO2 catalyst. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

The article presents research on waterborne polyurethane (WPU) adhesives modified by polystyrene (PS). In this study, proton nuclear magnetic resonance techniques were used to examine PS dispersions and (PU)-PS prepolymer. It was found that PS/polyester diol weight ratios improved several properties including thermal stability, mechanical properties and water resistance with regard to the performance of PU-PS adhesives.

The article presents a study which examined the synthesis and characterization of waterborne polyurethane adhesives (WPUA) prepared from diphenylmethane-4,4'-diisocyanate (MDI) and1,6-hexamethylene diisocyanate (HDI). The researchers measured the viscosity, mechanical properties, thermal properties and adhesion strength of the samples obtained. The advantages of using WPUA are also described.

3 wt% mini-sized graphene filled polyurethane exhibits improved 81% tensile strength and 126.7% modulus at an elongation of 605%, and 17 times thermal conductivity (4.24 W/m·K) over PU. There exist more hydrogen bonds and improved microphase separation of hard and soft segments for the reinforcement of polyurethane by mini-sized graphene. [Display omitted] • Graphene filler features small sheet size (300 × 400 nm) and low defects. • 3 wt% graphene filling polyurethane was optimized. • Improved 81% tensile strength, 126.7% modulus and 17 times thermal conductivity. • The reinforcement results from promoted microphase separation and hydrogen bonds. Graphene filler can improve certain properties of a polymer, but often compromises others, partially because it is difficult to control graphene size and dispersion at high content in polymer matrix. In this work, we present that mini-sized sheet sizes (300 × 400 nm) of graphene microsheets (mG) up to 7 wt% are filled in polyurethane (PU) reaching improved performances including mechanical properties (tensile strength, modulus, shape memory), electrical conductivity, thermal conductivity, thermal stability and flame retardance. The filling of 3 wt% mG in PU involves the enhancements of 81 % tensile strength (41.6 MPa at the elongation at break of 605 %), 126.7 % of modulus, 17 times of thermal conductivity (4.24 W/m·K) and 50℃ of thermal stability over net PU. The extensive characterizations disclose that hydrogen bonds strengthened and microphase separation promoted in the PU composite with the filling of the planar shape, hydrophilic edge and low defects of small graphene microsheets. This investigation presents a great potential of extending polymer materials with the filler of graphene microsheets derived from microcrystalline graphite minerals. [ABSTRACT FROM AUTHOR]

A series of waterborne polyurethanes (WPUs) were synthesized by a pre-polymer process from isophorone diisocyanate, 1,6-hexamethylene diisocyanate and polycarbonatediol with varying molecular weight (1000–2000 Da) and molecular structure (copolycarbonate and homopolycarbonate). The effect of polycarbonatediols on the performance of the emulsion was studied by means of apparent viscosity, particle size distribution and Zeta potential analysis. Fourier transform infrared spectroscopy, thermal gravimetric analysis, differential scanning calorimetry, X-ray diffraction, dynamic mechanical analysis, physical and mechanical measurements and water droplet contact angle tests were employed to characterize the thermal stability, crystallinity, low temperature flexibility, physical and mechanical properties and wettability of the films derived from the emulsions. The results indicated that WPU dispersions with mean particle size in the range of 50–70 nm and Zeta potential value about −50 mV displayed excellent storage stability. It was found that the mean particle size, thermal stability, crystallinity, low temperature flexibility, mechanical properties and hydrophobicity increased and the particle distribution decreased with the increase of molecular weight of the polycarbonatediols. Moreover, copolycarbonate-based WPUs showed higher crystallinity of hard segments, thermal stability and wettability than the homopolycarbonate-based ones. [ABSTRACT FROM AUTHOR]

• A novel amino-alcohol chain extender derived from CO 2 was synthesized. • The chain extender was used in the preparation of green waterborne polyurethane-urea. • CO 2 -AA based WPUs showed excellent water/solvents resistance and hydrolysis/oxidation resistance. • WPU films from CO 2 -AA chain extender showed promising mechanical performances and considerable thermal properties. Carbon dioxide based amino-alcohol compound (CO 2 -AA) with both alcohol and amino units in the molecular was prepared by chemical fixation of CO 2 with 1, 4-butanediol diglycidyl ether and ethylenediamine, which was further used as chain extender to the preparation of waterborne polyurethanes (CO 2 -WPUs). Since the reacting activity of isocyanate groups in WPU prepolymer with NH 2 was much faster than that with OH, hydroxyl groups could be maintained in the system and strengthen the hydrogen bonding interaction in WPU endowing the materials with some special properties. Specifically, the unique structure of CO 2 -AA improved mechanical, water/solvents resistance and hydrolysis/oxidation resistance properties of CO 2 -WPUs. Mechanical properties of the CO 2 -WPUs changed slightly during immersion in water, 0.25% NaOH and 6.00% H 2 O 2 solution, while the WPUs prepared from typical chain extender ethylenediamine almost lost their mechanical properties after immersed in the solutions for 5 h. Moreover, the CO 2 -WPU films showed considerable thermal stability. The study suggested the novel CO 2 -AA might be a promising chain extender to improve the water/solvent resistance and hydrolysis/oxidation resistance of WPU. [ABSTRACT FROM AUTHOR]