Diphenyl Diisocyanate Research Articles

High strength and transparent polyvinyl alcohol/nanocellulose film with encoding fluorescence properties

Fluorescent anti-counterfeiting films have garnered significant attention due to their advantages of tunable emission, strong concealment, high difficulty of imitation, and good processability. In this work, two zinc sulfide quantum dots (ZnS QDs) with different fluorescence wavelengths were loaded to construct polyvinyl alcohol (PVA)/cellulose nanofiber (CNF) composite films with encoding anti-counterfeiting fluorescence properties. By controlling the loading ratio of the two ZnS QDs, coded signals with different fluorescence intensity ratios at emission wavelengths of 400 nm and 600 nm were achieved. The fluorescence intensity ratio of the film can be adjusted between 1.3 × 105 and 1 × 10−4, resulting in a wide range of blue to orange color changes under ultraviolet light. The fluorescence intensity ratio corresponds to the color change of the film, which can be used for fluorescence coding design. By fine-tuning the addition ratio of the two types of QDs, the fluorescence intensity ratio and the color of the film can be precisely controlled, enhancing the anti-counterfeiting performance of the film. PVA is employed as a carrier to maintain high transmittance (> 80 %). The strength of the film was elevated up to 90 MPa due to the reinforcing effect of CNF, and the hydrophobic property was significantly improved with a contact angle higher than 113° through modification with diphenyl diisocyanate (MDI). This type of fluorescent PVA/CNF composite film, with its high mechanical strength and transparency, holds great potential in the field of anti-counterfeiting.

Production of Chemically Modified Shear Thickening Fluids and Investigation of Their Rheological Properties

In this study, the rheological properties of shear thickening fluid, which are generally used as single solid phase in the literature, were investigated by chemical material reinforcement. Considering that the unique shear thickening effect of STF is used in many areas such as increasing the impact resistance of fabrics and energy dissipation, this study aims to provide guidance for investigating what STFs can do with chemical bonds as well as physical bonding.Methylene diphenyl diisocyanate (MDI) was used in varying proportions for chemical reinforcement. When the rheological properties of the suspensions reinforced with MDI as a chemical additive were evaluated, the initial viscosity values increased as the MDI ratio increased, while the solidification behavior under shear was observed significantly in the sample with 2.5% MDI ratio with increasing shear ratio.

Evaluation of haematological, genotoxic, cytotoxic and ATR-FTIR alterations in blood cells of fish Channa punctatus after acute exposure of aniline

Aniline (C6H5NH2) an important intermediate in the organic and fine chemical industry, is ubiquitously used worldwide. It is one of the important building block for manufacturing of 4,4-methylene diphenyl diisocyanate (MDI), accelerators in rubber processing, dyes, tattoo inks, photographic chemicals, antioxidants, corrosion inhibitors, pharmaceuticals and antiseptics. The current study evaluated 96 h LC50 of aniline and based on this, two sublethal concentrations (4.19 mg/l and 8.39 mg/l) were selected for acute exposure studies in freshwater food fish Channa punctatus. Erythrocytes of fish are nucleated hence they play an important role in physiology, immune system, protein signalling and haemostatic condition along with respiration. Blood samples were collected after 24, 48, 72, and 96 h of exposure to study haematological, cytotoxic and genotoxic effects of sublethal concentrations of aniline in C. punctatus. Symbolic elevation in time and dose dependent DNA damage was observed by comet assay as well as micronuclei assay revealing maximum damage after 96 h of exposure. After aniline exposure, scanning electron microscopy and ATR-FTIR studies showed anomalies in structure and alterations in biomolecules of RBCs of aniline exposed group as compared to control group respectively. Semi prep HPLC studies revealed bioaccumulation potential of aniline in higher concentration exposed group.

Polyurethane Adhesives for Wood Based on a Simple Mixture of Castor Oil and Crude Glycerin

Developing a new type of polyurethane is essential because conventional options often exhibit shortcomings in terms of environmental sustainability, cost-effectiveness, and performance in specialized applications. A novel polyurethane adhesive derived from a simple mixture of castor oil (CO) and crude glycerin (CG) holds promise as it reduces reliance on fossil fuels and harnesses renewable resources, making it environmentally friendly. Simple CO/CG mixtures, adjusted at three different weight fractions, were used as bio-based polyester polyols to produce polyurethane adhesive for wood bonding. The resulting products are yellowish liquids with moderate-to-high viscosity, measuring 19,800–21,000 cP at 25 °C. The chemical structure of the polyester polyols was characterized using infrared spectroscopy (FTIR), thermogravimetry (TG), and differential scanning calorimetry (DSC). These polyols reacted with polymeric 4,4-methylene diphenyl diisocyanate (p-MDI) at a consistent isocyanate index of 1.3, resulting in the formation of polyurethane adhesives. Crucially, all final adhesives met the adhesive strength requirements specified by ASTM D-5751 standards, underscoring their suitability for wood bonding applications. The addition of CG enhanced the surface and volumetric hydrophobicity of the cured adhesives, resulting in adhesive properties that are not only stronger but also more weather-resistant. Although the thermal stability of the adhesives decreased with the inclusion of CG, FTIR analysis confirmed proper polyurethane polymer formation. The adhesive adjusted for a 2:1 CO:CG weight ratio promoted wood–wood bonding with the highest shear strength, likely due to a higher formation of urethane linkages between hydroxyl groups from the blend of polyols and isocyanate groups from the p-MDI.

Producing Polyurethane as Wound Plaster using Glycerol Transesterified of Waste Cooking Oil with Moringa Leaf Extract (Moringa Oleifera Lam.) as an Antimicrobial

Wound plaster polyurethane can make using glycerol from waste cooking oil (WCO). Wound plasters should contain antibacterial ingredients in addition to covering the sore. Traditionally various plants have been used to treat sore and contain sundry antibacterial chemical compounds amid Moringa oleifera Lam. Therefore, it is very potential to make polyurethane wound plasters from glycerol produced from WCO combined with Moringa leaf extract obtained from wound plasters from natural ingredients. Maceration with 96 % ethanol yielded moringa leaf extract. Then, a transesterification reaction carries out by using KOH-methanol at 60 °C to get glycerol and tested by FTIR spectrophotometry. Polyurethane wound plasters were made with a mixture of methylene 4,4 diphenyl diisocyanate, polyethylene glycol (PEG) and various formulas with variations of glycerol 0, 3, 6, 9, 12, 15 and 18 drops. A characteristic test enforced with swelling test to find the best formula and functional group analysis using FTIR spectrophotometry. Into the best wound plaster, improved Moringa leaf ethanol extract at an intensity of 1 - 5 %. An antibacterial activity test carries out on the Moringa leaf ethanol extract and plasters obtained by the agar diffusion method. The FTIR spectrophotometer test showed the formation of glycerol from WCO. The results of the characteristics test for polyurethane wound plaster preparations obtained the best formula using 3 drops of glycerol. The antibacterial activity test results at a concentration of 500 mg/mL Moringa leaf extract produced a muscular inhibition zone of 19.2 mm against Staphylococcus aureus and Antiseptic solution of 17.3 mm; Pseudomonas aeruginosa of 14.3 mm and Antiseptic solvent of 16.2 mm. Antibacterial activity of polyurethane wound plaster against Staphylococcus aureus contains 5 % ethanol extract of 10.3 mm, Plaster Merck X of 11.2 mm, Pseudomonas aeruginosa, only gave resistance at 5 % concentration of 8.3 mm and Plaster Merck X of 9.2 mm. HIGHLIGHTS Based on FTIR testing, it confirms the presence of aliphatic CH groups and OH groups, as well as the comparison of FTIR spectra with the raw material indicates the presence of Glycerol from Transesterification of Used Cooking Oil, and then the purification process of glycerol from used cooking oil yielded 30.4 g Glycerol from the transesterification reaction of WCO is used to create polyurethane wound dressings by forming urethane groups (-NHCO), as indicated by the FTIR results of the best formula using 3 drops of glycerol The Moringa leaf extract in the polyurethane wound dressing formula shows antibacterial activity GRAPHICAL ABSTRACT

Effect of Glue Spread on Bonding Strength, Delamination, and Wood Failure of Jabon Wood-Based Cross-Laminated Timber Using Cold-Setting Melamine-Based Adhesive.

Cross-laminated timber (CLT) has become a popular engineered wood product due to its innovative properties and rapid development, which involves the use of various wood species and adhesives. This study aimed to assess the effect of glue application on the bonding strength, delamination, and wood failure of CLT made from jabon wood and bonded with a cold-setting melamine-based adhesive at three different rates: 250, 280, and 300 g/m2. The adhesive was composed of melamine-formaldehyde (MF) by adding 5% citric acid, 3% polymeric 4,4-methylene diphenyl diisocyanate (pMDI), and 10% wheat flour. Adding these ingredients increased the adhesive viscosity and decreased the gelation time. The CLT samples, made using cold pressing in the melamine-based adhesive at a pressure of 1.0 MPa for 2 h, were evaluated as per the standard EN 16531:2021. The results revealed that a higher glue spread resulted in a greater bonding strength, lower delamination, and a higher wood failure. The glue spread was shown to have a more significant influence on wood failure compared with delamination and the bonding strength. The application of 300 g/m2 glue spread (MF-1) on the jabon CLT led to a product that met the standard requirements. The use of modified MF in cold-setting adhesive produced a potential product that could be a feasible option for future CLT production in terms of its lower heat energy consumption.

One-Shot Synthesis of Thermoplastic Polyurethane Based on Bio-Polyol (Polytrimethylene Ether Glycol) and Characterization of Micro-Phase Separation.

In this study, a series of bio-based thermoplastic polyurethane (TPU) was synthesized via the solvent-free one-shot method using 100% bio-based polyether polyol, prepared from fermented corn, and 1,4-butanediol (BDO) as a chain extender. The average molecular weight, degree of phase separation, thermal and mechanical properties of the TPU-based aromatic (4,4-methylene diphenyl diisocyanate: MDI), and aliphatic (bis(4-isocyanatocyclohexyl) methane: H12MDI) isocyanates were investigated by gel permeation chromatography, Fourier transform infrared spectroscopy, atomic force microscopy, X-ray Diffraction, differential scanning calorimetry, dynamic mechanical thermal analysis, and thermogravimetric analysis. Four types of micro-phase separation forms of a hard segment (HS) and soft segment (SS) were suggested according to the [NCO]/[OH] molar ratio and isocyanate type. The results showed (a) phase-mixed disassociated structure between HS and SS, (b) hydrogen-bonded structure of phase-separated between HS and SS forming one-sided hard domains, (c) hydrogen-bonded structure of phase-mixed between HS, and SS and (d) hydrogen-bonded structure of phase-separated between HS and SS forming dispersed hard domains. These phase micro-structure models could be matched with each bio-based TPU sample. Accordingly, H-BDO-2.0, M-BDO-2.0, H-BDO-2.5, and M-BDO-3.0 could be related to the (a)—form, (b)—form, (c)—form, and (d)—form, respectively.

Design of Acrylate-Terminated Polyurethane for Nylon Seamless Bonding Fabric Part I: Design of the End-Capping Thermoplastic Polyurethane Adhesive with Acrylate Copolymer.

This series of studies aims to design acrylate-terminated polyurethanes for use in nylon seamless bonded fabrics. The first part used N,N-dimethylacrylamide (DMAA) and methyl methacrylate (MMA) to replace the chain extender in polyurethane synthesis as end-capping agent to synthesize thermoplastic polyurethane (TPU) adhesive. The molecular weight of the TPU is controlled to further influence the mechanical and processing properties of the polyurethane. Here, polytetramethylene ether glycol (PTMG) and 4,4-methylene diphenyl diisocyanate (MDI) were polymerized, and then a blocking agent was added thereto. The results show that the characteristic peaks of benzene ring and carbamate of TPU adhesive are at 1596 cm−1 and 1413 cm−1, respectively, while the characteristic peaks of DMAA are at 1644 cm−1 and 1642 cm−1 in the FT-IR spectrum. There is an absorption peak –N=C=O– which is not shown near 2268 cm−1, which proves that the structure of TPU contains the molecular structure of capping agent, PTMG and MDI. When the DMAA concentration in the capping agent was increased from 3.0 wt% to 10 wt%, the –C=O (H-bond) area percentage of hydrogen bonds formed at 1711 cm−1 increased from 41.7% to 57.6%, while the –NH (H bond) produced at 3330 cm−1 increased from 70% to 81%. These phenomena suggest that increasing the concentration of DMAA capping agent can effectively promote the formation of complex supramolecular network structures by hydrogen bonding in TPU. The content and concentration of the capping agent affects the molecular weight of the TPU. Chain growth is terminated when molecular weight growth can be effectively controlled and reduced. It was observed in thermal analysis that with increasing DMAA concentration in the molecular structure, the concentration of capping agent in TPU, hydrogen bonding force between hard segments, melting point (Tmh) and melting enthalpy (ΔH) all increased the capping agent. The pyrolysis temperature of TPU is increased by 10–20 °C.

The biocomposites properties of compounded poly(lactic acid) with untreated and treated spent coffee grounds

AbstractPoly (lactic acid) (PLA) is a biodegradable and environmentally friendly material. And the spent coffee grounds (SCG) are huge waste all over the world. Therefore, the issue that how to convert the low‐value wastes SCG into more valuable products is attracting more research attention. In this work, we compounded PLA with SCG. Firstly, the efficiency of oil extraction from SCG was compared by different methods and solvents. Then, the biocomposites specimens of different SCG contents (0, 5, 10, and 15 wt%) were prepared by extrusion and injection molding. The effects of SCG particle size and content on the thermal and mechanical properties were investigated. Next, the effect of coupling agent (4,4‐methylene diphenyl diisocyanate [MDI]) on the biocomposites properties at 10 wt% SCG was examined by Field emission‐scanning electron microscope and Fourier transform infrared spectroscopy. The results show that the tensile strength and elongation at break of the PLA composites with the optimal contents are increased by about 50% and 120%, respectively, compared with untreated SCG.

Effects of Isocyanate-to-Polyols (NCO/OH) Ratio on Bio-based Polyurethane Film from Palm Kernel Oil based Monoester Polyols (PKO-p) for Polymer Electrolytes Application

This study investigated the synthesis of bio-based polyurethane (PU) film from palm kernel oil-based polyols (PKO-p) at four different isocyanate-to-polyols (NCO/OH) ratios comprising 100/100, 100/150, 100/200, and 100/250. The PU film was prepared by mixing 2,4-methylene diphenyl diisocyanate (MDI) and PKO-p in acetone using the pre-polymerization technique under a nitrogen atmosphere at room temperature. The effect of the NCO/OH ratio on the properties of the PU films was analyzed through infra-red spectroscopy, molecular weight distribution, thermal behavior, and impedance spectroscopy. According to the infra-red spectroscopic analysis, the formation of urethane linkages (–NHCOO–) after the polymerization was indicated through the disappearance of isocyanate (N=C=O) peak and the appearances of secondary amine, carbonyl, carbamate, ether, and ester groups in the PU chain. In addition, the Gel Permeation Chromatography (GPC) showed that the weight of average molecular weight (MW) increased with increasing NCO/OH ratio up to 1.23 × 106 g mol-1. Nevertheless, higher content of PKO-p resulted in a low crosslink PU (4 % crosslink) and poor physical properties such as soft, sticky, and easy to tear due to the non-hydrogen bonded urethane. Moreover, the glass-transition temperature (Tg) reduced from 67 °C to 30 °C with the increase in PKO-p content. Despite all samples experienced the same thermal stability at 187 °C, a significant difference was observed in the mass loss of NCO/OH ratios. The highest thermal degradation was found at (100/200) NCO/OH ratio with Tmax = 444 °C. Furthermore, the piezoelectricity characteristic of pristine PU recorded the bulk resistant of up to ~107 – 105 Ω which reduced further after the presence of lithium iodide (LiI) salts as the charge carrier with the calculated ionic conductivity around 10-5 S cm-1. Thus, this study demonstrated the promising physicochemical properties of PU film from PKO-p for polymer electrolyte application.

Tunable shape memory property polyurethane with high glass transition temperature composed of polycarbonate diols

AbstractA series of polyurethane (PU) copolymers was synthesized by 4,4‐Methylene diphenyl diisocyanate (MDI) with different polyols of polyether, polyether carbonate (PEC), and polycarbonate with the same molecular weight via a one‐step copolymerization process. The synthesized PU containing the ether carbonate groups exhibited a relatively higher glass transition temperature (Tg) above 45°C; in comparison, a value of 12.4°C for the polycarbonate sample and −22°C for the polyether sample was observed. The film made of PEC samples produced by solvent indicated an increment of Tg from 14.6 to 59.6°C after annealing for 6 h, which might be due to the rearrangement of chain structure, which led to an assembling of carbonate groups and resulted in a hindrance of chain mobility. For shape memory examination of the PU copolymers, all samples showed remarkable ability as recovery rate above 91% after 3 cycles test. PEC‐type PU polymers reveal potential high‐temperature micro shape memory material applications.

Modification of Ramie Fiber via Impregnation with Low Viscosity Bio-Polyurethane Resins Derived from Lignin.

The purpose of this study was to prepare low-viscosity lignin-based polyurethane (LPU) resins for the modification of ramie (Boehmeria nivea (L.) Gaudich) fiber via impregnation to improve the fiber’s thermal and mechanical properties. Low-viscosity LPU resins were prepared by dissolving lignin in 20% NaOH and then adding polymeric 4,4-methane diphenyl diisocyanate (pMDI, 31% NCO) with a mole ratio of 0.3 NCO/OH. Ramie fiber was impregnated with LPU in a vacuum chamber equipped with a two-stage vacuum pump. Several techniques such as Fourier-transform infrared (FTIR) spectroscopy, differential scanning calorimetry, thermogravimetric analysis, pyrolysis-gas chromatography–mass spectroscopy, field emission-scanning electron microscopy coupled with energy dispersive X-ray (EDX), and a universal testing machine were used to characterize lignin, LPU, and ramie fiber. The LPU resins had low viscosity ranging from 77 to 317 mPa·s−1. According to FTIR and EDX analysis, urethane bonds were formed during the synthesis of LPU resins and after impregnation into ramie fibers. After impregnation, the reaction between the LPU’s urethane group and the hydroxy group of ramie fiber increased thermal stability by an average of 6% and mechanical properties by an average of 100% compared to the untreated ramie fiber. The highest thermal stability and tensile strength were obtained at ramie impregnated with LPU-ethyl acetate for 30 min, with a residual weight of 22% and tensile strength of 648.7 MPa. This study showed that impregnation with LPU resins can enhance the thermal and mechanical properties of fibers and increase their wider industrial utilization in value-added applications.

Flexible silicone rubber/carbon fiber/nano-diamond composites with enhanced thermal conductivity via reducing the interface thermal resistance

Abstract Insulating materials with heat dissipation are urgently required for modern electronic devices and systems. In this study, 4,4-methylene diphenyl diisocyanate was used as the coupling agent, and nano-diamond (ND) particles were grafted onto the surface of carbon fibers (CFs) to prepare CF-ND/silicone rubber (SR) composites. The ND acted as a “bridge” among CFs, which can reduce the interface thermal resistance between CFs because the dot-like ND can increase the interfacial area of CFs, making it easier to form heat-conducting networks between SR. When the content of CF-ND (1:6) was 20%, the thermal conductivity of the SR composite was 0.305 W/(m·K), 69% higher than that of pure SR. The ND between CFs can improve the dynamic mechanical properties by acting as a crack pinhole. In addition, the CF-ND/SR composites also exhibited excellent thermal stability. This work has enormous potential for advanced electronic devices.

Performance of eco‐friendly particleboard from agro‐industrial residues bonded with formaldehyde‐free natural rubber latex adhesive for interior applications

AbstractIn this work, a novel way is proposed to produce an eco‐friendly and formaldehyde‐free particleboard (PB) panel from agro‐industrial residues bonded with natural rubber latex (NRL)‐based adhesive. Polyvinyl alcohol (PVOH) was added as an adhesion promoter and polymeric 4,4‐methylene diphenyl diisocyanate (pMDI) was used as cross‐linker. Different formulations of agro‐industrial residues (cassava stem, sengon wood waste, and rice husk) and different contents of NRL‐adhesive (10%, 15%, and 20%) were applied to prepare the PB panel. Several techniques were performed to characterize the properties of NRL‐based adhesive and to evaluate the performance of PB panels from agro‐industrial residues bonded with NRL‐based adhesive. The blending of NRL and PVOH resulted in weak hydrogen bonds in the polymer blends. Incorporation of pMDI provided NCO groups as the reactive site for cross‐linking with NRL‐PVOH via urethane linkages. The results showed that no remarkable differences in the physical properties of the PB panel, such as density, moisture content, water absorption, and thickness swelling, with different agro‐industrial residues formulations and NRL‐adhesive content. By contrast, greater NRL‐adhesive content affected the mechanical properties of the PB panel. The best mechanical properties of the PB panel were obtained using a formulation of 40% of cassava stem, 30% of sengon wood waste, 30% of rice husk, and bonded with 20% of NRL‐adhesive content, which resulted in 4.02 MPa of modulus of rupture (MOR), 441.00 MPa of modulus of elasticity (MOE), and 0.19 MPa of internal bonding (IB) strength. A combination of agro‐industrial residues particles and NRL‐based adhesive presented a high potential for application as an eco‐friendly, formaldehyde‐free, and non‐structural PB such as interior applications.

Enhancing Thermal and Mechanical Properties of Ramie Fiber via Impregnation by Lignin-Based Polyurethane Resin

In this study, lignin isolated and fractionated from black liquor was used as a pre-polymer to prepare bio-polyurethane (Bio-PU) resin, and the resin was impregnated into ramie fiber (Boehmeria nivea (L.) Gaudich) to improve its thermal and mechanical properties. The isolated lignin was fractionated by one-step fractionation using two different solvents, i.e., methanol (MeOH) and acetone (Ac). Each fractionated lignin was dissolved in NaOH and then reacted with a polymeric 4,4-methane diphenyl diisocyanate (pMDI) polymer at an NCO/OH mole ratio of 0.3. The resulting Bio-PU was then used in the impregnation of ramie fiber. The characterization of lignin, Bio-PU, and ramie fiber was carried out using several techniques, i.e., Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), pyrolysis-gas-chromatography-mass-spectroscopy (Py-GCMS), Micro Confocal Raman spectroscopy, and an evaluation of fiber mechanical properties (modulus of elasticity and tensile strength). Impregnation of Bio-PU into ramie fiber resulted in weight gain ranging from 6% to 15%, and the values increased when extending the impregnation time. The reaction between the NCO group on Bio-PU and the OH group on ramie fiber forms a C=O group of urethane as confirmed by FTIR and Micro Confocal Raman spectroscopies at a wavenumber of 1600 cm−1. Based on the TGA analysis, ramie fiber with lignin-based Bio-PU had better thermal properties than ramie fiber before impregnation with a greater weight residue of 21.7%. The mechanical properties of ramie fiber also increased after impregnation with lignin-based Bio-PU, resulting in a modulus of elasticity of 31 GPa for ramie-L-isolated and a tensile strength of 577 MPa for ramie-L-Ac. The enhanced thermal and mechanical properties of impregnated ramie fiber with lignin-based Bio-PU resins could increase the added value of ramie fiber and enhance its more comprehensive industrial application as a functional material.

Polyvinylpyrrolidone-Stabilized Iridium Nanoparticles Catalyzed the Transfer Hydrogenation of Nitrobenzene Using Formic Acid as the Source of Hydrogen

Catalytic nitrobenzene reduction is crucial for the synthesis of 4,4-methylene diphenyl diisocyanate, which is used to produce polyurethane foams, thermoplastic elastomers, and adhesives. The stability and activity of nanoparticle catalysts are affected by surface ligands and stabilizers. We established the complete composition of 7.0 ± 1.1 nm iridium oxide nanoparticles that were stabilized by polyvinylpyrrolidone (PVP[Ir]). PVP[Ir] and its surface stabilizers were characterized using elemental analysis (EA), high-resolution X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (PXRD), FT-IR, and UV-vis spectroscopy. Notably, PVP[Ir] contained 33.8 ± 0.4% Ir. XPS binding energy analyses suggest that 7% of the Ir is Ir(0) and 93% is IrO2. Using formic acid as the source of hydrogen, PVP[Ir] catalyzed the selective hydrogenation of nitrobenzene to give aniline as the only product in 66% yield in 1 h at 160 °C in a high-pressure metal reactor. Less than 1% of the side products (azobenzene and azoxybenzene) were detected. In contrast, using alcohol as the hydrogen source led to a low yield and a poor selectivity for aniline.

Shape memory thin films of polyurethane: Synthesis, characterization, and recovery behavior

AbstractPolyurethane thin films with inherent two phase segregated characters are exceptional candidates for the development of shape memory materials. However, controlling the phase behavior of such complex structures for decoding their recovery behavior still experiences its early stage of development. In this work, polyurethane thin films were synthesized based on two polyols, ester‐based polyols (ESP), and ether‐based polyols (ETP) together with diphenyl diisocyanate (MDI). The effects of ingredient ratio of PETP (ether‐based prepolymer)/PESP (ester‐based prepolymer) on the chemical structure and final properties of polyurethanes were studied by the Fourier‐transformed infrared spectroscopy (FTIR), the differential scanning calorimetry (DSC), the scanning electron microscopy (SEM), the dynamic mechanical thermal analysis (DMTA), a tensiometer, and the atomic force microscopy (AFM). The shape memory behaviors were explored by the thermomechanical cycles applied by a DMTA device in the controlled force mode. The PU films showed various properties compared with the bulk PU since they formed spherulitic textures with different structures. All the PU films except PU‐0 showed high shape recovery ca. 90% in the first cycle with a large glassy storage modulus in the range of 2,800–4,040MPa, and a recovery ratio enhanced by increasing the number of cycle to a maximum of 95%.

Fabrication of New Thermoplastic Polyurethane Elastomers with High Heat Resistance for 3D Printing Derived from 3,3-Dimethyl-4,4′-diphenyl Diisocyanate

Thermoplastic polyurethane (TPU) have received considerable attention because of their flexible structure and comprehensive performance. 3,3-dimethyl-4,4'-diphenyl diisocyanate (TODI) was first int...

Poly(lactic acid)-based Composites Incorporated with Spent Coffee Ground and Tea Leave for Food Packaging Application: A Waste to Wealth

Polymer composites of polylactic acid (PLA) and polybutylene adipate terephthalate (PBAT) incorporated with spent coffee grounds (SCG) and tea leave (TL) were prepared by two-roll mill mixer. 4,4-methylene diphenyl diisocyanate (MDI), toluene 2,4-diisocyanate (TDI), and bis[3-(triethoxysilyl) propyl] tetrasulfide (TESPT) were used as coupling agents. The influences of coupling agent types, coupling agent content, and weight ratios of polymer to filler on the mechanical properties, melt flow index, and overall migration (OM) of the composites were studied. The results showed that MDI and TDI had better performance compared to TESPT for both tensile and elongation at break. The tensile strength and elongation at break of PLA+PBAT/SCG composites with weight ratio of polymer to filler = 70/30 increased from 19.6 MPa to ∼23.0 to 25.0 MPa, and 6.6 to ∼10.0%, respectively when using these coupling agents (MDI and TDI) of 3 g/100 g polymers. Moreover, the addition of MDI and TDI greatly increased the viscosity of the melted composites (4-fold), while TESPT made the viscosity decrease. However, the mechanical properties of the composites decreased drastically with increasing SCG proportion. Compared to PLA+PBAT/SCG, interfacial adhesion of PLA+PBAT/TL was higher confirming by tensile strength and SEM images. However, there was no significant difference between PLA+PBAT/TL and PLA+PBAT/SCG composites in terms of elongation at break, impact strength and melt flow index. The OM of PLA+PBAT/SCG and PLA+PBAT/TL composites with coupling agents were in the range of ∼0.03–0.28 mg/dm2 when using 3% acetic acid and 10% ethanol as food simulants, which not excess the migration limit (10 mg/dm2) according to Food Contact Materials EU No. 10/2011 legislation. It means that they might be safe for use as food contact materials for packaging and containers.

Evaluation of respiratory exposure to 4,4-methylene diphenyl diisocyanate (MDI) vapors in foam injection workers in a household appliance manufacturing company: An Occupational Carcinogen

Background: Appliance manufacturing boom is very high hand customers always have a great deal of attention to products that have low energy consumption, therefore the use of isocyanates MDI as a thermal insulation in the body of the refrigerator and is also widely used as a binder in the production of washing machines. MDI isocyanate study the effects on the respiratory capacity of formers injection was done foam material in a household appliance company
 Method: this case control study in 1395 and a household appliance manufacturing company in the province of Qazvin 20 personnel working injected foam material is exposed to isocyanates ,for example administrative personnel and 20 served as controls using medical records these values breathing capacity FVC , FEV1 , FEV1/FVC in both 1390 and 1394 extracted using SPSS software and paired T-TEST data were analyzed.
 Results: Measuring the concentration of isocyanate in 90 blocks in the cabin and tap lid above the limit, which was due to the failure of the ventilation system, in 94 years due to the good performance of the ventilation system in the isocyanate concentration was at the limit. According to their experiences foam material is injected every three indexes FVC, FEV1, FEV1/FVC had significant losses, FEV1 and FVC decline among which were a significant level. (p=0.036, p= 0.008) the control samples also non- significant decline in the indicators that this can be attributed to aging.
 Conclusion: It is known that exposure to isocyanate materials decreased respiratory capacity is personnel, to postpone it to the desired function ventilation system. it would be desirable to postpone the operation of the ventilation system and non-isocyanate leak on the ground, work, be a lot of attention. even with the improvement of the job must be conservative’s injection foam material is exposed to isocyanates be included in the list of hard and hazardous jobs. 
 Keywords: MDI, respiratory exposure, respiratory capacity, workers inject foam material.