Isophorone Diisocyanate Research Articles

Evolution of HTPB/RDX/Al/DOA mixed explosives with 90% solid loading in resonance acoustic mixing process

ABSTRACT Resonance acoustic mixing (RAM) technology is an attractive and safe mixing method for material mass and energy exchange. However, the mixing mechanism of this technology and the evolution law of the material in the container are complicated, and improper mixing conditions will make the material unable to reach uniformity quickly and efficiently. In this paper, a 90% solid polymer-bonded explosive (PBX) was prepared by RAM, and the evolution of materials in different mixing containers, mixing acceleration, and mixing time was studied. The binder system consisted of hydroxyl-terminated polybutadiene (HTPB)/dioctyl adipate (DOA) and was cured by isophorone diisocyanate (IPDI). Scanning electron microscopy (SEM) and Energy dispersive spectroscopy (EDS) were used to observe the microcosmic change of the sample during the mixing process, and a rheometer was used to measure the viscosity change of the slurry at different stages. The results showed that the hemispherical bottom vessel could achieve uniform mixing of materials within 45 minutes, and the mixing efficiency was highest when the acceleration was 40 g. According to the evolution state of typical materials, the mixing process was divided into 3 stages: rough cladding stage, the stage of converging into a smooth ball, and the flat fluidization stage. In the range of shear rates from 0.1 to 100s−1, the apparent viscosity of the material tended to be flat with the extension of mixing time, and the rheological behavior index of the material had little change after the material aggregates into a smooth ball. The density test of the cured sample further proved that the PBX was very uniform.

Synthesis and characterization of hydrophobic properties of silicon dioxide in palm oil based bio-coating

This research aims to synthesize a biobased polyurethane coating from epoxidized palm oil (EPO) and determine the effect of different silicon dioxide (SiO2) loadings on the hydrophobicity performance of the coating. In this work, EPO was firstly undergoing an acrylation reaction and followed by the addition of isophorone diisocyanate (IPDI) to form Polyurethane (PU). Improvement was made by adding SiO2 at different loadings into the palm oil-based PU to provide hydrophobic properties to the coating materials. The sample was characterized using Fourier Transform Infrared Spectroscopy (FTIR), water sliding angle test, and water absorption test. Based on the FTIR results, PU was successfully synthesized from EPO with SiO2 addition. The results also proved that the addition of SiO2 successfully improved the hydrophobicity of the coating. The higher the SiO2 content in palm oil PU, the shorter the time taken for the water to slide down the 25° angle coated glass and lower the water absorption percentage of the coating material. Based on the analysis, 3 phr SiO2 content showed the highest hydrophobicity performance, which could be applied in further research.

Controllable preparation of isophorone diisocyanate microcapsules with silica/polyurea hybrid shells and application in self-healing epoxy coatings

Isophorone diisocyanate (IPDI) microcapsules with silica/polyurea hybrid shells were successfully synthesized via interfacial polymerization and in situ polymerization in an oil/water emulsification system. The micromorphology and surface silicon species-modified microcapsules were studied by scanning electron microscopy and X-ray photoelectron spectroscopy. The components of the microcapsules were analysed by Fourier transform infrared spectroscopy. The resultant microcapsules have diameters of 76.5 ± 16.5 μm, shell thicknesses of approximately 2.3 μm, and core fractions of 76.5 wt%. Meanwhile, the thermal stability, storage stability and solvent resistance of the microcapsules were evaluated. The results showed that silica/polyurea microcapsules had excellent thermal stability with the initial decomposition temperature, increasing by approximately 92 °C compared with that of polyurea microcapsules. More than 65.0 wt% active core fraction of silica-modified microcapsules was reserved after six months in air or 40 days in water. The microcapsules were incorporated into epoxy resin coatings. The scratch and self-healing test of the coatings proved that the silica-modified microcapsules healed the scratch successfully.

Palm Oil Based Water-Resistant Coating using Pre-Polymer Method

The paper presents some results on the ability of palm oil polyol to replace the petroleum-based polyol in polyurethane (PU) synthesis. In this study, palm oil polyol with amine functionality with hydroxyl value (OH value) between 240 -253 mg KOH/g was used as the polyol component to replace the conventional petroleum-based polyol. Four different formulationsof polyurethane coating have been prepared using pre-polymer process namely PU1, PU2, PU3 and PU4 with the polyol to isophorone diisocyanate ratio (OH:NCO) of 1:0.6 and 1:0.5 and acetone within 25-50 wt %. PU1 (1:0.6) and PU2(1:0.5) result in brittle film, while PU3 (1:0.6) and PU4 (1:05) has a soft and flexiblefilm with better transparency. This finding establishes that the acetone content effect the final properties of the polyurethane formed. The polymerization reaction was monitored using thefourier transform infra-red spectroscopy and it was found that the peak correspondsto NH (3302 cm-1), CO (1627 cm-1) and CN (1543 cm-1) stretching of urethane linkage appearingin all the PU films. The water uptake test was done on the films and it was found that the percentage of water uptake is less than 5% within 24 hours of immersion.The surface morphology of the PU films shows thathomogeneitywas achieved in 1:0.6 of OH:NCO ratio with 25 wt% of acetone. The PU films havethe potential to be developed for water resistant coating.

Polyurethane films prepared with isophorone diisocyanate functionalized wheat starch

This study reports the fabrication and performance of sustainable polyurethane (PU) films based on wheat starch (native NS, modified MS), bio-polyols (1,3-propanediol PD, glycerol Gly), and polymeric diphenylmethane diisocyanate (pMDI). NS was successfully modified with isophorone diisocyanate, confirmed by Fourier transform infrared spectroscopy (FTIR) and 13C nuclear magnetic resonance (13C NMR). Various PU films were prepared using NS, PD or Gly, MS and pMDI. For comparison, reference films were also synthesized without MS. PU films were analyzed from the viewpoint of their chemical, thermomechanical and flexural properties, and microstructural morphology. FTIR spectra demonstrated the total consumption of NCO groups, while the scanning electron microscopy micrographs of the films revealed that MS addition promoted the interactions between the compounds, enhancing in consequence their mechanical and thermomechanical performance. The study supported the suitability of functionalized carbohydrates to substitute petrochemical compounds in the synthesis of more environmentally-friendly PUs.

A novel polyfunctional polyurethane acrylate prepolymer derived from bio-based polyols for UV-curable coatings applications

In recent decades, the sustainability, availability and low toxicity of biomass polyols have attracted more and more attention. Biomass polyols were used to prepare polyfunctional polyurethane acrylates, which can effectively improve the green performance of UV-curable coatings. Herein, a multifunctional polyurethane acrylate containing a variety of biomass was synthesized and characterized. Firstly, itaconic acid (IA), ricinoleic acid (RA) and oleic acid (OA) reacted with glycidyl methacrylate (GMA) respectively to obtain itaconic acid acrylate (IAG), ricinoleic acid acrylate (RAG) and oleic acid acrylate (OAG). Determination of the synthesis of IAG, RAG and OAG was conducted by proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared spectroscopy (FTIR). Then IAG, RAG, OAG and castor oil (CO) were mixed and reacted with isophorone diisocyanate (IPDI) to prepare polyurethane acrylate. The effects of IAG, RAG, OAG and CO on the thermal and mechanical properties of polymers were studied. The results showed that when the content of IAG was increased, the double bond conversion rate, the glass transition temperature, tensile strength, Young's modulus and gel content of polyurethane increased significantly. In addition, by adjusting the contents of IAG, RAG, OAG and CO, the thermal stability of polymers also showed regular changes. Among them, the thermal stability of polymers increased most with the increase of IAG content, followed by RAG, OAG and CO.

Catalytic effects over formation of functional thermoplastic elastomers for rocket propellants

AbstractRheometry was the main method to characterize the curing process of binders made of functional polyurethanes (PUs). The macroglycols characterization by means of additional techniques, such as nuclear magnetic resonance, size exclusion chromatography, and differential scanning calorimetry, provided further information for the chemorheological description. Materials were based on Butacene ((ferrocenylbutyl)dimethylsilane grafted to hydroxyl‐terminated polybutadiene (HTPB)), used in the solid propulsion field. First, the flow parameters for the uncured reactive mixtures of Butacene and four different diisocyanates were analyzed via viscometry and these were markedly influenced by the chemical structure of the curing agents. Analyzing the rheokinetic constant values of the pre‐gel stage for Butacene‐ and HTPB‐reactive systems, relevant catalysis caused by the ferrocene moiety was detected when aliphatic reactants were used, such as isophorone diisocyanate or 1,6‐hexamethylene diisocyanate (IPDI and HMDI, respectively). No catalytic effect was found for 2,4‐toluene diisocyanate (2,4‐TDI) or even for 4,4′‐methylenediphenyl diisocyanate (4,4′‐MDI). Finally, the use of dynamic rheology was useful to evaluate the critical points during gelation process, where the reactivity of curing agents was associated with the achievement of elastic properties. Both techniques agreed the reactivity order of curing agents with Butacene, which is 4,4′‐MDI > HMDI > > 2,4‐TDI ≥ IPDI. The knowledge of the structure–reactivity relationship and, moreover, the kinetics of the urethane network formation for these metallo‐PUs is paramount in manufacturing processes for advanced thermoplastic elastomer applications.

Syntheses and Characteristics of Urushiol-Based Waterborne UV-Cured Wood Coatings.

The manufacture and properties of waterborne UV-cured coatings (WUV coatings) by acetone process based on urushiol for wood finishing were investigated. Firstly, epoxide urushiol (EU) was prepared by reacting urushiol with epichlorohydrin. Secondly, the EU was reacted with acrylic acid to obtain acrylic epoxide urushiol (AEU). Next, the prepolymers were synthesized by the reaction of AEU, 2,2-Bis(hydroxymethyl)propionic acid (DMPA), and isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI), respectively, using acetone as a solvent. The prepolymers were further neutralized by triethylamine (TEA) to obtain ionomers and dispersed in the water. After removing the acetone by vacuum distillation, the polyurethane dispersions (PUDs) were obtained. Finally, the WUV coatings were performed by adding a photoinitiator (Irgacure 2959). The products in the synthesized processes and the properties of the WUV coatings were examined. The results showed that the EU, AEU, prepolymers, and ionomers could be synthesized stably. The PUDs synthesized by the IPDI and HDI had a similar solid content of 25.2% and 26.2%, and similar pH values of 7.8 and 7.6. However, the IPDI-containing PUD displayed lower viscosity, smaller particle size, and a more even polydispersity index. The IPDI-containing WUV film displayed a higher hardness, gloss, and lightfastness. The HDI-containing WUV film possessed superior impact resistance. Both IPDI-containing and HDI-containing WUV films showed excellent adhesion, bending resistance, and mass retention, and demonstrated a potential for wood finishing.

Biooxazolidines‐Enabled Improvement of Monocomponent Polyurethane Coatings

AbstractSingle‐component moisture‐cured polyurethane (SPU) possesses the merit of easy preparation and high curing efficiency but suffers from poor apparent properties, mechanical performance, and thermal stability. Herein, the authors employ isophorone diisocyanate (IPDI) and 2‐isopropyl‐3‐hydroxyethyl‐1, 3‐oxazolidines (IHO) to synthesize oxazolidine (termed as IPDI‐IHO) for the subsequent modification of SPU. The structure and composition of the synthesized SPU/IPDI‐IHO composites are unraveled by 1H and 13C NMR and FTIR spectroscopies. Apart from the curing properties of SPU/IPDI‐IHO, the apparent properties, mechanical performance, thermal stability, and self‐healing ability are evaluated. SEM and AFM characterizations reveal that IPDI‐IHO incorporation significantly decreased the number of bubbles and thus reduce the SPU‐based sample surface roughness. The thermal stability of SPU is notably improved after IPDI‐IHO modification. The tensile strength and elongation at break also increases from 830 to 3710 kPa and from 210% to 600%, respectively, due to IPDI‐IHO inclusion, with the optimal mechanical properties achieved at the IPDI‐IHO mass ratio of 8 wt%. Furthermore, the cracks intentionally cut for the SPU/IPDI‐IHO sample can be self‐healed at 60 °C. The ensemble of the performance enhancements suggests that the IPDI‐IHO developed in this work opens up a new route to fabricate high‐performance SPU and related polymeric materials.

4D-actuators by 3D-printing combined with water-based curing

The shape and the actuation capability of state of the art robotic devices typically relies on multimaterial systems from a combination of geometry determining materials and actuation components. Here, we present multifunctional 4D-actuators processable by 3D-printing, in which the actuator functionality is integrated into the shaped body. The materials are based on crosslinked poly(carbonate-urea-urethane) networks (PCUU), synthesized in an integrated process, applying reactive extrusion and subsequent water-based curing. Actuation capability could be added to the PCUU, prepared from aliphatic oligocarbonate diol, isophorone diisocyanate (IPDI) and water, in a thermomechanical programming process. When programmed with a strain of εprog= 1400% the PCUU networks exhibited actuation apparent by reversible elongation ε'rev of up to 22%. In a gripper a reversible bending ε'rev(bend) in the range of 37–60% was achieved when the actuation temperature (Thigh) was varied between 45 °C and 49 °C. The integration of actuation and shape formation could be impressively demonstrated in two PCUU-based reversible fastening systems, which were able to hold weights of up to 1.1 kg. In this way, the multifunctional materials are interesting candidate materials for robotic applications where a freedom in shape design and actuation is required as well as for sustainable fastening systems.

Thermo- and UV-responsive amphiphilic nanogels via reversible [4+4] photocycloaddition of PEG/PCL-based polyurethane dispersions

Amphiphilic nanogels are emerging as promising materials for several applications due to their high loading capacity of hydrophobic substances. In this context, a thermoresponsive anthracene end-capped hyperbranched polyurethane (HPU-AM) based on poly(ethylene glycol), polycaprolactone-triol, and isophorone diisocyanate, was used as a platform for nanogel preparation. Both polymer synthesis and functionalization with anthracene were one-pot and controlled. HPU-AM self-assembled in aqueous solutions to form micelles, while heating above the solution cloud point (Tcp) led to phase separation and globule formation, as verified by 1H nuclear magnetic resonance and dynamic light scattering experiments. Nanogel dispersions were prepared by UV-irradiation of the globule dispersions. The UV-light (λ = 365 nm) triggers the [4+4] cycloaddition of the anthracene chain-ends, yielding chemically cross-linked nanogels. Their hydrodynamic radius was tuned from 28 to 50 nm by varying the quench temperature (T > Tcp) and HPU-AM concentration. Evidence of nanogel softness, spherical morphology, narrow size distributions, and phase-segregated inner structure was provided by microscopy, light scattering, and Nile-red loading experiments. The hydrodynamic volume of the nanogels was reversibly reduced up to 85% by heating from 15 to 45 °C. Finally, irradiation of the nanogel dispersions at λ = 280 nm cleaved the anthracene dimer, partially reverting the crosslinking, and promoting nanogel disaggregation into micelles of hydrodynamic radius of 7 nm.

Self‐healing behavior in blends of PDMS‐based polyurethane ionomers

AbstractIonic interactions offer the highest non‐covalent cohesive strength in supramolecular assemblies. In spite of that, they have been consistently underestimated in the development of self‐healing materials due to their lack of directionality and association specificity. In this paper, ionic moieties are introduced as side‐chain pendants in poly(urea‐urethane) siloxane‐based polymers, aiming to obtain a strong yet flexible elastomer with the capability to recover from a damaged state. The synthesis was carried out by a two‐step polymerization involving polydimethylsiloxane (PDMS) diamine‐terminated, isophorone diisocyanate (IPDI) and a chain extender providing the required ionic functionality. Internal phase separation allowed the material to show its elastomeric behavior. After preparation of the blend by mechanical mixing, the formation of ionic interactions was checked for by FT‐IR spectroscopy, rheological analysis and tensile tests. Healing of notch damage was evaluated both with respect to tensile strength and fracture toughness. At room temperature (21°C) and humidity (30% RH) the maximum recovery measured at 14 days was 47%. Self‐healing dependence on humidity and temperature was assessed, resulting in further improvements (up to 100%) as molecular mobility was increased by both conditions.

A novel water borne green textile polyurethane dispersions finishes from cotton (Gossypium arboreum) seed oil based polyol used in modification of cellulosic fabrics

Now in these days the major challenges in the polymer industry is to evolve sustainable and renewable substitutes to petroleum-based raw resources. Keeping in view of the current challenges a novel series of water-borne polyurethane dispersions were prepared from the renewable resource cottonseed oil-based polyol by varying the polyol contents concerning the 1,4-butanediol. The polyol was prepared by epoxidation and ring-opening procedure and further reacted with the isophorone diisocyanate, dimethylol propionic acid, and 1,4-butanediol to form the final polyurethane dispersions. The FTIR technique was used to confirm the anticipated structure of cotton seed oil-based polyol and final polyurethane dispersions. Different textile tests such as anti-pilling and colorfastness properties were carried out onto the plain weave fabrics of poly/cotton after applying the synthesized dispersions by pad-dry-cure processes. Significant improvement in anti-pilling behavior was shown by the white grade (4), dyed (4), and printed (4/5) fabrics from the untreated fabrics (1/2), (1/2), and (2), respectively. However, colorfastness properties of all the treated fabrics also showed the remarkable enhancement in rating as compared to the untreated fabrics such as colorfastness to rubbing of the dyed fabric improved to grade (3/4) and (4/5) from the untreated fabrics (2) and (3) for wet and dry rubbing. The results revealed that the bio-based polyol in the polyurethane backbone has significantly improved the fabric properties and has applications for better textile performance for polyester/cotton textiles to substitute the petroleum raw material-based finishes.

Cell Adhesion on UV-Crosslinked Polyurethane Gels with Adjustable Mechanical Strength and Thermoresponsiveness.

Temperature-responsive polyurethane (PU) hydrogels represent a versatile material platform for modern tissue engineering and biomedical applications. However, besides intrinsic advantages such as high mechanical strength and a hydrolysable backbone composition, plain PU materials are generally lacking bio-adhesive properties. To overcome this shortcoming, the authors focus on the synthesis of thermoresponsive PU hydrogels with variable mechanical and cell adhesive properties obtained from linear precursor PUs based on poly(ethylene glycol)s (pEG) with different molar masses, isophorone diisocyanate, and a dimerizable dimethylmaleimide (DMMI)-diol. The cloud point temperatures of the dilute, aqueous PU solutions depend linearly on the amphiphilic balance. Rheological gelation experiments under UV-irradiation reveal the dependence of the gelation time on photosensitizer concentration and light intensity, while the finally obtained gel strength is determined by the polymer concentration and spacing of the crosslinks. The swelling ratios of these soft hydrogels show significant changes between 5 and 40°C whereby the extent of this switch increases with the hydrophobicity of the precursor. Moreover, it is shown that the incorporation of a low amount of catechol groups into the networks through the DMMI dimerization reaction leads to strongly improved cell adhesive properties without significantly weakening the gels.

Conductive and room-temperature self-healable polydimethylsiloxane-based elastomer film with ridge-like microstructure for piezoresistive pressure sensor

The fabrication of piezoresistive pressure sensor with self-healing function has attracted worldwide attention for its great prospects in intelligent robots, remote health monitoring and electronic skin. In this work, a conductive and self-healable elastomer (CSE) film with ridge-like microstructure was designed for flexible piezoresistive pressure sensor. Firstly, self-healable polydimethylsiloxane (PDMS)-based elastomer with ureido and imine groups was synthesized via a simple one-pot two-step polycondensation reaction with aminopropyl-terminated PDMS, isophorone diisocyanate and 1, 3, 5-triformylbenzene as monomers. Secondly, the synthesized PDMS-based elastomer solution was casted onto a sandpaper pre-sprayed with ureido pyrimidinone grafted carbon nanotubes/polyurea mixed solution, and the CSE film was obtained after drying and peeling off from the sandpaper. The piezoresistive pressure sensor fabricated with two single-electrode CSE films exhibited high sensitivity of 8.7 kPa−1 (0–6.1 kPa), low detection limit (50 Pa), fast response capability (response/relaxation time of 40/117 ms) and repeatability for 10,000 loading–unloading tests. Moreover, the sensor was able to fully recover to normal work after healing for 36 h at room temperature or even 200 s under the irradiation of near infrared (NIR) light. Importantly, the sensor was successfully applied for not only detecting human motions including radial pulse, speech recognitions and joint movements but also monitoring health status wirelessly through Bluetooth transmission. Our findings put forward a novel method to fabricate a high-performance self-healable piezoresistive sensor for wearable electronics, healthcare monitoring and electronic skin.

Multifunctional waterborne polyurethane films: Amine-response, thermal-driven self-healing and recyclability

Currently, the preparation and application of functional waterborne polyurethane has become a research hotspot in the field of polyurethane. In the present work, Different weight ratios of diacetyl oxime and coumarin diol were used as the reactive filler with isophorone diisocyanate (IPDI) and Poly propylene glycol (PPG) to prepare superior amine-response, self-healing and recyclable waterborne polyurethane films (WPU-x). Dynamic mechanical analysis was carried out to identify the self-healing properties of WPU-x. It was revealed that the WPU-2 film show an excellent self-healing capability based on the combination of the mobility of the soft segment, dynamic reaction of oxime carbamate bond and hydrogen bonds, and the mechanical properties self-healing efficiency can reach 91.11% after self-healing at 90 °C for 7 h. UV testing and fluorescence imaging results shown that WPU-2 film exhibit a rapid and concentration-dependent response to dimethylamine (DMA), and it also shows varying degrees of response to other organic amines. The WPU-2 film could be readily applied in cold chain transportation of shrimp and fish for real-time and visual monitoring the freshness of seafoods. At the same time, the WPU-2 film could be recycled via hot-pressing and solution casting. Therefore, this strategy provides some insights for preparing multi-functional waterborne polyurethane.

Biobased Waterborne Polyurethane-Ureas Modified with POSS-OH for Fluorine-Free Hydrophobic Textile Coatings.

Waterborne polyurethane-urea dispersions (WPUD), which are based on fully biobased amorphous polyester polyol and isophorone diisocyanate (IPDI), have been successfully synthesized obtaining a finishing agent that provides textiles with an enhanced hydrophobicity and water column. Grafting of trans-cyclohexanediol isobutyl POSS (POSS-OH) to the biobased polymer backbone has also been investigated for the first time and its properties compared to a standard chain extender, 1,3-propanediol (PDO). The chemical structure of WPUD has been characterized by Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The thermal properties have been evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Mechanical properties have been studied by tensile stress–strain analysis. Moreover, the particle size, particle size distribution (PSD), and stability of developed waterborne dispersions have been assessed by dynamic light scattering (DLS), Z-potential, storage aging tests, and accelerated aging tests by analytical centrifuge (LUM). Subsequently, selected fabrics have been face-coated by the WPUD using the knife coating method and their properties have been assessed by measuring the water contact angle (WCA), oil contact angle (OCA), water column, fabric stiffness, air permeability, and water vapor resistance (breathability). Finally, the surface morphology and elemental composition of uncoated and coated fabrics have been studied by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), respectively. All of the synthesized polyurethane-ureas provided the coated substrates with a remarkable hydrophobicity and water column, resulting in a more sustainable alternative to waterproof coatings based on fluoropolymers, such as PTFE. Grafting POSS-OH to the polymeric backbone has led to textile coatings with enhanced hydrophobicity, maintaining thermal, mechanical, and water column properties, giving rise to multifunctional coatings that are highly demanded in protective workwear and technical textiles.

An environment-friendly wood adhesive using modified wheat gluten by isophorone diisocyanate

A highly efficient method was developed for preparing wheat gluten (WG) based wood adhesives with high performance using ethanol and isophorone diisocyanate (IPDI) as main chemical additives. The performance of the resulting adhesives was evaluated by manufacturing artificial wood products (AWP). The effects of IPDI content on the water resistance, viscosity, solid content and modification mechanism of the adhesives and the optimal method to prepare artificial wood products were investigated. The results showed that ethanol could disperse the stacked protein structures and expose some internal groups of proteins, so that IPDI could be cross-linked with protein molecules to form a more compact three-dimensional reticulum protein structure, confirmed by both the increases of the decomposition temperature and the smoother and more uniform surface of the resulting adhesives. The structural changes enhanced the hydrophobicity of the modified adhesive samples and were beneficial to resist the invasion of water molecules, which improved the water resistance of the adhesives. When the IPDI concentration was 15 wt%, the dry and wet shear strength of the adhesive reached 2.61 MPa and 0.97 MPa with the best water resistance respectively, and the viscosity and solid content increased to 32.8 Pa·s and 34.41 %, respectively. It was found that the resulting adhesives had better performance and could be used as an environment-friendly plywood adhesive instead of petroleum-based adhesive, which was more conducive to the extension of the wheat industry chain to high value-added products.

Shape memory characteristics of thermadapt polyurethane incorporated with two structurally distinctive aliphatic isocyanates

Shape memory polymers (SMPs) have the ability to fix a temporarily deformed shape and recover its original shape. Owing to the shape memory effect, SMPs have been widely investigated for applications in various industries. Shape memory polyurethane (SMPU) is a common SMP material which possesses good shape memory and mechanical properties, and it is mostly focused on the thermoplastic SMPU. In this study, we introduced two structurally different aliphatic isocyanates, hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI), to fabricate thermadapt SMPUs. The formation of the hard segment in the SMPU matrix was tunable by varying the IPDI mol% of the total isocyanate content. The shape memory characteristics were strongly related to the contents of the hard segments and the crystallinity of the thermadapt SMPU. Owing to the transcarbamoylation reaction between the carbamate moieties, the network of our thermadapt SMPU can be rearranged to redefine its permanent shape, and the redefined shape can also be recovered from the temporarily deformed state.

Synthesis and application of hybrid waterborne polyurethane/acrylate dispersion with diol grafting agent containing carbon–carbon double bond

AbstractIn this work, polyurethane/acrylate waterborne hybrid polymer (WPUA) colloids were synthesized by grafting with a new diol agent containing carbon–carbon double bond to create chemical bonds between polyurethane and polyacrylate chains. WPUAs were obtained by a solvent‐free and surfactant‐free method with isophorone diisocyanate (IPDI), poly(tetrahydrofuran) (PTMG), 2,2‐bis(hydroxymethyl)butyric acid, and diol grafting agent in the polyurethane part, and methyl methacrylate, n‐butyl acrylate, and octadecyl acrylate in the polyacrylate portion. When the R value was 1.5 and WPU/PA was 5:5, hybrid WPUA dispersion was obtained with the satisfied particle size and colloidal stability. WPUA dispersion was applied on textile substrates for water repellent. Scanning electron microscope results showed that WPUA covered the fabric surface and formed a thin film. Contact angle measurements of water have revealed that the addition of WPUA to the textile improved the water repellency and increased the contact angle to 152°. Moreover, WPUA coated fabrics had good durability against washing. After 50 laundering cycles, the static water contact angle of the fabric coated with the WPUA could maintain at 143°.