Waterborne polyurethane-silica nanocomposite adhesives based on castor oil-recycled polyols: Effects of (3-aminopropyl)triethoxysilane (APTES) content on properties

Waterborne castor oil-recycled polyol based polyurethane-silica nanocomposite adhesives (WPU) with polymer matrix and silica nanoparticles chemically bonded have been successfully prepared through a sol-gel process. A series of waterborne polyurethane adhesives with hard segment contents from 71.3 to 74.5 wt%, were synthesized using an isophorone diisocyanate, 2-bis(hydroxymethyl) propionic acid, recycled castor oil-based as soft segments and (3-aminopropyl)triethoxysilane (APTES) as chain extender. The depolymerized oligoester obtained from glycolysis of poly(ethylene terephthalate) (PET) waste using triethylene glycol (TEG), was transesterified with castor oil (CO) which resulted in the formation of hydroxyl-functional polyester polyol, with hydroxyl value of 414 mgKOH g⁻¹. The molecular structures and mass of glycolyzed PET oligoesters, castor oil-based polyol and castor oil-based polyurethane-silica nanocomposite adhesives were estimated by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). The structure and properties of the resulting films were investigated by FTIR, wide angle X-ray diffraction measurement (XRD), thermogravimetry (TG) and differential scanning calorimetry (DSC). TG analysis indicated that APTES can improve the thermal stability of WPU. XRD showed that the crystallinity of WPU decreased with the increase alkoxysilane content. The extent of crosslinking was investigated to show a dependence on silica concentration, which increased the glass transition temperature and particle size of polyurethane nanocomposites with increasing alkoxysilane content due to the condensation of the alkoxysilane groups. The hardness, adhesion and gloss quality of the polyurethane films were also determined considering the effect of APTES content, so this paper confirmed the suitability of using these castor oil-based waterborne polyurethane-silica nanocomposites as new adhesive materials with high performance coatings materials. The experimental results reveal that the APTES and the hard segment content play a key role in controlling the structure and properties of the PU cast films based on castor oil-recycled polyols.     

Effect of special structure of clam shell powder on structure and properties of castor oil-based composites

Castor oil (CO) is an environmentally friendly renewable green resource and ideal alternative to petroleum resources. The preparation of high strength and high toughness castor oil-based polyurethane prepolymer (COPU) composites has significant applications such as supporting material and engineering plastic sheet. In this study, unmodified clam shell powder (CSP) with a unique CaCO₃-proteoglycan structure was used as a filler to prepare compatible reinforced COPU composite materials. Investigation of the mechanical properties revealed that the elastic modulus of the composite COPU reinforced with 50 wt% of CSP had increased to 5859.0 ± 8.4 MPa representing 187.77% to obtain stiffer and stronger material over pure COPU (2036.6 ± 196.9 MPa). Moreover, the scanning electron microscopy, thermogravimetric analysis and contact angle results demonstrated that the reinforced COPU composites have better compatibility, thermal stability, and water resistance than pure COPU. This work will promote the application prospects of CO-based polyurethane.     

PDMS改性蓖麻油基水性聚氨酯的制备及防污性能

本研究以低成本的二甲基二甲氧基硅烷为主要原料，通过水解缩合反应制备合成了聚二甲基硅氧烷（PDMS），进而将其引入蓖麻油基水性聚氨酯（CWPU-SOP）中制备了具有防污性能的蓖麻油基水性聚氨酯(PDMS/CWPU-SOP)。结果表明，当PDMS引入量为8%时，与CWPU-SOP薄膜相比，PDMS/CWPU-SOP薄膜接触角提高了25?，达110?，PDMS/CWPU-SOP薄膜的吸水率下降了7%，为15%；PDMS提高了薄膜疏水性和耐水性。PDMS/CWPU-SOP薄膜在不同酸碱性的液滴在其表面可自由滚落且不留痕迹，具有一定的防污性能。     

Preparation and characterization of waterborne polyurethane/silica hybrid dispersions from castor oil polyols obtained by glycolysis poly(ethylene terephthalate) waste

Castor oil polyols (COLs) have been synthesized from glycolyzed oligoester polyol in order to produce waterborne polyurethane (WPU)/silica hybrid dispersions. Soft drinks poly(ethylene terephthalate) (PET) bottles were depolymerized by glycolysis with different molar ratio of poly(ethylene glycol) ( PEG 400), in the presence of zinc acetate as catalyst. The obtained glycolyzed products were reacted with castor oil (CO) to attain castor oil polyols by the process of transesterification. Five castor oil polyols were used with hydroxyl values of 255, 275, 326, 366 and 426 mg KOH g⁻¹. Several castor oil-based, polyurethane/silica hybrid dispersions having soft segment content of 39.6% to 28.2% and two concentrations of SiO₂ nanoparticles (0.5 and 1.0) have been prepared.The incorporation effect of SiO₂ nanoparticles into the PU matrix and the hydroxyl functionality of the COLs on the thermal and mechanical properties of resulting polyurethane films has been examined by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetric analysis (TG) and measurement of the mechanical properties. The degree of phase separation (DPS) between oxide nanoparticles and hard segment, and particle size in the polyurethane, depends to some extent on nanosilica content and the hydroxyl functionality of the polyols employed in the polyurethane preparation process.Thermal stability of obtained hybrid materials depends on the hydroxyl functionality of the COLs and nanosilica content. The T_10% and T_50% (the temperature where 10 and 50% weight loss occurred) of WPU films decreased with the rise of OH functionality of castor oil polyols, caused by the increase of hard segment content. Glass transition temperature increased with increasing OH functionality and SiO₂ content. The hardness, adhesion and gloss quality of the polyurethane films were also determined with a view to assessing the effect of mole ratios of PET to glycol in glycolyzed products, the hydroxyl functionality and the SiO₂ content.     

A fully bio-based waterborne polyurethane dispersion from vegetable oils: From synthesis of precursors by thiol-ene reaction to study of final material

A new linear saturated terminal diisocyanate was synthesized from castor oil-derived undecylenic acid by thiol-ene coupling (TEC) and Curtius rearrangement. The structure of the diisocyanate was carefully examined using Fourier transform infrared spectroscopy, ¹H nuclear magnetic resonance (NMR), and ¹³C NMR. This diisocyanate was used as a starting material for the preparation of a fully bio-based waterborne polyurethane dispersion (BPUD) by reacting with castor oil and castor oil-based carboxylic acid-type hydrophilic chain extender, which was prepared from castor oil by using 3-mercaptopropionic acid via TEC. The thermal/mechanical properties of the formed BPUD film were characterized via differential scanning calorimetry, thermogravimetric analysis, tensile test, hardness test, and water resistance test. The fatty acid-derived diisocyanate and the castor oil-based hydrophilic chain extender were used to produce BPUD with favorable properties.     

Vegetable Oil-Based Hyperbranched Thermosetting Polyurethane/Clay Nanocomposites

The highly branched polyurethanes and vegetable oil-based polymer nanocomposites have been showing fruitful advantages across a spectrum of potential field of applications. Mesua ferrea L. seed oil-based hyperbranched polyurethane (HBPU)/clay nanocomposites were prepared at different dose levels by in situ polymerization technique. The performances of epoxy-cured thermosetting nanocomposites are reported for the first time. The partially exfoliated structure of clay layers was confirmed by XRD and TEM. FTIR spectra indicate the presence of H bonding between nanoclay and the polymer matrix. The present investigation outlines the significant improvement of tensile strength, scratch hardness, thermostability, water vapor permeability, and adhesive strength without much influencing impact resistance, bending, and elongation at break of the nanocomposites compared to pristine HBPU thermoset. An increment of two times the tensile strength, 6 °C of melting point, and 111 °C of thermo-stability were achieved by the formation of nanocomposites. An excellent shape recovery of about 96–99% was observed for the nanocomposites. Thus, the formation of partially exfoliated clay/vegetable oil-based hyperbranched polyurethane nanocomposites significantly improved the performance.     

Synthesis and characterization of novel renewable castor oil-based UV-curable polyfunctional polyurethane acrylate

In recent years, a lot of interest has been given to renewable resources for their environmental friendliness and potential biodegradability in the synthesis of urethane-derived polymers. In this work, UV-curable castor oil-based polyfunctional polyurethane acrylate (COPUA) was prepared by the reaction of isophorone diisocyanate (IPDI) with castor oil and pentaerythritol triacrylate (PETA). The structures and molecular weights of the targeted IPDI–PETA and COPUA were characterized by FTIR, ¹H NMR, and GPC, respectively. In addition, the effect of reactive diluent content on damping properties, thermal stabilities, and mechanical properties of COPUA was characterized by dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and universal test machine. DMA revealed the copolymers had a glass transition temperature (T _g) from 31.81 to 48.09°C. TGA showed that thermal initial decomposition temperatures were above 344.5°C, indicating the copolymers had certain thermal stability. Finally, some physical properties of curing films were studied by the contact angle and water absorption, and the results showed that the coatings exhibited good hydrophobicity. The COPUA obtained from castor oil can be used as eco-friendly materials and other applications alternative to the use of other petrochemicals in coatings.     

Castor oil-based paper packaging coating with water resistance and degradability obtained by thiol-ene click reaction

With the implementation of plastic restrictions and the increasingly serious problem of environmental pollution, paper with green and recyclable characteristics is gradually becoming a substitute for packaging materials. However, the rich cellulose structure in the paper, which contains hydroxyl groups leading to its hydrophilicity, allows water molecules to penetrate the paper and disrupt the hydrogen bonds between cellulose, resulting in a decrease in mechanical properties. Therefore, waterproof coatings are crucial for paper-based materials to be used in many applications. Based on this, the paper surface was chemically modified with castor oil-based resin (CO-590) monomer prepared by coupling agent and castor oil (CO). The results indicated that the modified paper with the contact angle (CA) of 114° had excellent waterproof performance and had a reduction by 40.3% in water vapor transmission rate (WVTR), but also its mechanical increased to 26.9 MPa and the decomposition temperature to 410.5°C. In addition, the coating on its surface could be removed in an alkaline solution and had a possibility to recycle blank paper in the future for manufacturing sustainable production. This work not only provides a method for preparing modified packaging paper, but also expands the application fields of materials.     

Modified cellulose nanocrystals enhancement to mechanical properties and water resistance of vegetable oil-based waterborne polyurethane

Environmentally friendly and lightweight silylated cellulose nanocrystal (SCNCs)/waterborne polyurethane (WPU) composite films that exhibit excellent mechanical properties and water resistance were prepared. The cellulose nanocrystals (CNCs) of the filamentous structure were surface-modified by γ-aminopropyltriethoxysilane (APTES) and then introduced into a castor oil-based aqueous polyurethane (WPU) matrix by in situ polymerization. The morphology and silylation degree of CNCs were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier infrared transform spectroscopy at different APTES concentrations. The results showed that the surface of the nanocellulose crystal has the best silylation morphology and thermal stability with incorporation of 6 wt % APTES. The thermal stability, mechanical properties, surface morphology, and water resistance of the nanocomposites were investigated by TGA, tensile test, SEM and optical contact angle, water absorption test, and mechanical property test after immersed in water. It was found that the effective introduction of modified CNCs resulted in a significant increase in tensile strength at high levels, and the thermal stability and hydrophobicity of the material were improved simultaneously, reaching the percolation threshold at a 0.50 wt % SCNCs as determined theoretically. This study provided an approach to the design and development of surface-modified CNCs/vegetable oil-based polymer composites by using an appropriate concentration of silane coupling agent to modify CNCs and improve the compatibility between nanocellulose and vegetable oil-based polymer matrices. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48228.     

The effect of chain extenders structure on properties of new polyurethane elastomers

Two series of polyurethane elastomers were synthesized to investigate what effect does the incorporation of various new chain extenders have on the mechanical and thermal properties of polyurethane elastomers. The polyurethane soft segments were based on poly(ε-caprolactone) polyol. The hard segment was based on 1,6-hexamethylene diisocyanate in combination with 2,5-dimethyl-3-hexine-2,5-diol (DHD), hexaethylene glycol, glycerin, or castor oil. The results showed that the degradation rate and mechanical properties of the final products can be controlled through the structure of diol chain extenders or/and hard segment cross-linking present in the polyurethane elastomers. The DHD-based polyurethane displayed a relatively low glass transition temperature of −57 °C and a tensile strength of 11–14 MPa and elongation at break of 600–700%. These kinds of materials have potential application in many domains.     

The performance of CNT as catalyst support on CO oxidation at low temperature

A carbon nanotube (CNT) was used as catalyst support impregnated with transition metal cobalt for CO oxidation at low temperature. Catalyst properties were analyzed by X-ray powder diffractometer (XRD), X-ray photoelectron spectrometer (XPS), and transmission electron microscope (TEM). Analytical results for TEM and XRD demonstrated that cobalt particles were highly dispersed on the carbon nanotube (20–30 nm) with nanosized cobalt particles (10–15 nm). These investigations indicated that Co/CNT generates about 99% of the high activity for CO conversion at 250 °C and thermally stability that is superior to Co/activated carbon (AC). The optimum reaction conditions for CO conversion were O₂ concentration 3%, operation temperature 250 °C, CO concentration 5000 ppm, and space velocity 156,000 h⁻¹. At 250 °C, CO may act as a reductant for NO reduction over Co/CNT in the presence of oxygen, whereas CO/NO = 2.5 showed that maximum NO reduction was 30%. Under H₂ rich conditions, the optimum reaction temperature for CO conversion was under 300 °C, and performance of CO₂ selectivity was better at 200 °C than 250 °C as the oxygen concentration increased.     

Preparation and characterization of modified castor oil via photo-click chemistry for UV-curable waterborne polyurethane with enhanced water resistance and low conductive percolation threshold

A castor oil (CO) was modified via thiol-ene click chemistry reaction between CO and 3-mercaptopropyl trimethoxysilane, with the conversion of CC bonds of CO over 99% based on ¹HNMR spectra. The obtained modified castor oil (MCO) was used as a biobased polyol to prepare waterborne polyurethane (WPU) dispersions. The modification of CO exhibited a great effect on the properties of WPU dispersions and coatings, and an obvious change is the improvement of the water resistance of WPU coatings. WPU dispersions with MCO had good storage stability. A WPU coating with 7% MCO had high surface hydrophobicity, and its water absorption was as low as 3.2%. Conductive carbon black filled WPU coatings with MCO were cured by efficient UV radiation, and their conductive percolation threshold could decrease to 0.76%, which could be attributed to the well filler dispersion and strong filler-polymer interaction. The WPU dispersions are ecofriendly, and can be used to produce biobased WPU coatings with a great application potential in antistatic coating fields.     

Morphology and mechanical properties of UV-curable castor oil-based waterborne polyurethane/organic montmorillonite nanocomposites

Water resistance is a unique advantage of castor oil-based polyurethane, permitting the application of coatings in humid environments. However, its low thermal decomposition temperature remains a limitation. Here, to demonstrate a simple method to improve the thermal stability of cured films, we prepared an organic montmorillonite dispersion utilising 3-(methacryloyloxy)propyltrimethoxysilane and protonated 3-aminopropyltriethoxysilane for modifying the clay. The method was put into practice by directly mixing the dispersion with a UV-curable castor oil-based waterborne polyurethane dispersion. The inclusion of organic molecule chains from the silane coupling agents noticeably improves the compatibility of polyurethane with organic montmorillonite, which imparts the composite latex with better thermal stability and mechanical properties when the organic montmorillonite additive is 5.0?wt-%.     

Enzymatic Synthesis of an Isopropyl Ester by Alcoholysis of Camellia Oil

A camellia oil-based isopropyl ester (CO-IPE) was successfully synthesized by enzymatic alcoholysis with camellia oil (CO), and its physiochemical properties were analyzed. Three commercial immobilized lipases (Lipozyme RM IM, Lipozyme TL IM and Novozym 435) were screened, and Novozym 435 was the best one. The optimal reaction conditions were achieved at 240 U/g of Novozym 435 loading, a substrate molar ratio of 5:1 (isopropanol/CO), and 24 h of reaction time at 55 °C. Under the above conditions, the content of CO-IPE was obtained as 89.83%. Purity of CO-IPE further increased to be 96.95% after separation by rotary evaporation and molecular distillation. The viscosity of the synthesized CO-IPE showed itself to be about six times lower than that of CO, and the refractive index of the CO-IPE (1.449) was nearer to 1 in contrast to that of CO. It suggested that CO-IPE could be more intensively applied in the cosmetic industry.     

Comparative Study of Table Margarine Prepared from Moringa oleifera Seed Oil‐Palm Stearin Blend and Commercial Margarines: Composition,Thermal, and Textural Properties

This study aims to produce an oleic acid‐rich table margarine from Moringa oleifera seed oil (MoO)‐palm stearin (PS) blend (70:30, w/w) and compare its composition, thermal behavior, and textural properties during storage with those of commercial margarines (CM1 and CM2). The major fatty acid in MoO/PS blend, CM1 and CM2 is oleic acid (67.85%, 38.54%, and 35.35%, respectively). Hence, many of their triacylglycerols are derived from the acid. MoO/PS blend has a higher complete melting temperature (43.50 °C) compared to CM1 (35.50 °C) and CM2 (35.53 °C). The solid fat content (SFC) of MoO/PS blend at 10 °C (28.7%) is lower than CM1 (32%) and CM2 (68.4%). However, the MoO/PS blend has a higher SFC (6.47%) at 35 °C compared to CMs. At 20 °C, the viscosity of experimental blend margarine (EBM) decreases but CM1 and CM2 increase at the end of the storage study. After 8 weeks of storage, all margarines are harder and CM2 is the hardest. The adhesiveness of EMB and CM2 is similar to the fresh samples while CM1 is more adhesive after storage. In short, it is possible to produce an oleic acid‐enriched margarine from MoO/PS blend that has better textural properties. Practical Applications: Moringa oleifera seed oil is one of the superior oils that contains high levels of oleic acid. However, its high iodine value and low melting point limit its application in the production of margarine. This study shows that direct blending of M. oleifera seed oil with palm stearin could produce margarine with high oleic acid contents and better textural properties in terms of viscosity, hardness, and adhesiveness. The informative data provide supporting evidence for blending of M. oleifera seed oil with palm stearin to produce margarine that could overcome the issues that hinder the M. oleifera seed oil from being produced into margarine.     

蓖麻油基下游产物及蓖麻油增塑剂的研究及其应用进展

随着全球化石资源消耗量的不断剧增, 能源危机问题引起了广泛的关注。在植物资源能源化的利用中, 以蓖麻油为原料开发高附加值下游产品已成为研究热点。本文介绍了国内外蓖麻油基下游产品的制备方法、产品性能及应用领域等方面。回顾了脱水蓖麻油、酯交换蓖麻油、环氧化蓖麻油、蓖麻油基聚氨酯等下游产物的制备与应用性能研究。简述了蓖麻油基增塑剂的种类及应用领域, 具体分析了环氧乙酰蓖麻油酸甲酯的制备方法及产品特性。提出了在我国蓖麻油基增塑剂的生产过程中反应温度、催化剂用量等因素影响环氧基团稳定性的问题, 指出目前我国催化合成蓖麻油基增塑剂的趋势和发展方向。     

Polymers from renewable resources. XX. Synthesis,structure, and thermal properties of semi-interpenetrating polymer networks based on cardanol–formaldehyde-substituted aromatic compounds copolymerized resins and castor oil polyurethanes

A large number of improved high-temperature stable semi-interpenetrating polymer networks (semi-IPNs) were synthesized by condensing copolymerized resins with castor oil-based polyurethane using ethylene glycol dimethacrylate (EGDM) as a crosslinker. The structures of these semi-IPNs were studied using various characterization techniques such as IR and nuclear magnetic resonance (NMR) spectra, and the thermal behavior of the semi-IPNs was also studied by thermogravimetric analysis (TGA). A plausible degradation mechanism was suggested in our previous communication. © 1998 John Wiley & Sons, Inc. J Appl Polm Sci 70: 837–842, 1998     

Synthesis and properties of castor oil-based waterborne polyurethane cloisite 30B nanocomposite coatings

Waterborne polyurethane dispersions (WPUDs) were synthesized successfully from castor oil-based polyol, isophorone diisocyanate and dimethylol propionic acid with NCO/OH ratio of 1.5. Different weight percentages of cloisite 30B (1, 2, and 3 wt%) were loaded with WPUDs to prepare nanocomposite films. Prepared prepolymer and nanocomposite films were characterized using FTIR, XRD, SEM, TEM, DSC, and TGA techniques, and coating properties, such as pencil hardness, abrasion resistance, impact resistance, and contact angle, were evaluated. The results obtained from different amounts of clay loading were compared with the pristine castor oil-based WPUDs. The FTIR spectra deconvolution technique was used to study the hydrogen bonding effect within the polymer with an increase in clay content. TGA analysis showed that the thermal stability of WPUDs increases with cloisite 30B (C30B) content. The surface morphology and hydrophilicity/hydrophobicity nature of the nanocomposite films were characterized using scanning electron microscopy and contact angle measurement. The results obtained from tensile tests indicated that the mechanical property of the dispersion system improved with C30B content. A high-performance castor oil-based nanocomposite coating with low volatile organic component can be targeted as an outcome of this work.     

Growth and surface engineering of vertically-aligned low-wall-number carbon nanotubes

A novel catalyst of cobalt supported by single crystal MgO was prepared by atomic layer deposition and used for carbon nanotube growth. With CO as carbon source, vertically-aligned carbon nanotubes with predominant double-walled (82%) were produced at 700 °C. Similar carbon nanotube array with a majority of single-walled tubes (62%) was produced at 900 °C using methane as the carbon source. Due to their high flexibility compared with multi-walled carbon nanotubes, the low-wall-number carbon nanotube array could form a 3-dimensional honeycomb-like network when being spread with acetone.     

Synthesis and properties of siloxane-crosslinked polyurethane-urea/silica hybrid films from castor oil

A novel hybrid diol (HD) crosslinker has been synthesized with hydrolyzable –Si–OR groups from 3-amino propyl trimethoxy silane and 3-glycidoxy propyl trimethoxy silane. Its chemical structure was confirmed by Fourier transform infrared spectroscopy, ¹H and ¹³C nuclear magnetic resonance spectroscopy to introduce it as a crosslinker in the castor oil, a renewable resource, to develop functional organic inorganic hybrid coatings. A series of castor oil-based organic–inorganic hybrid materials were prepared from castor oil, isophorone diisocyanate, and the different weight percentages of synthesized HD. Dynamic mechanical thermal analysis, thermogravimetric analysis, differential scanning calorimetry, and the universal testing machine were employed to characterize the hybrid films. The measured properties were found to be strongly influenced by the weight ratio of HD to the castor oil-based polyurethanes. The glass transition temperatures (T _g) for the cured hybrid films were found to be 26–72°C. Antibacterial activity, in vitro hydrolytic degradation, and swelling properties of the hybrid films have been studied. The cured hybrid films exhibited excellent antibacterial activity, which was enhanced with addition of the HD. The alkoxy silane-crosslinked castor oil-based coatings have shown better mechanical and viscoelastic properties in comparison to the control (uncrosslinked castor oil-based polyurethane-urea) coatings. The results showed that the weight percent of the HD is the main factor that controls the thermal, antimicrobial, mechanical, swelling, and degradation properties of these hybrid films.