Production Of Polyurethane Foams Research Articles

Layer-by-layer coated cellulose reduces the fire risk of polyurethane foam biocomposites

Cellulose implementation as filler in polyurethane foams (PUF) often leads to an increased the fire risk associated to the prepared biocomposite. To address this problem, this paper presents a novel approach where the cellulose filler is coated by a nanostructured layer-by-layer (LbL) assembly with flame retardant characteristics before its addition to the biocomposite. During PUF production, the presence of cellulose led to a reduced cell size distribution with improved thermal insulation properties. By forced combustion tests, the use of neat cellulose produced a detrimental effect by increasing the PUF heat release rates (up to +21 %). Conversely, the coated cellulose simultaneously decreased the peak of heat release rate (-22 %) and the total smoke release (-32 %) if compared with the reference PUF. The proposed approach represents a viable strategy for the production of PUF biocomposites where sustainability and fire protection are optimized.

Eco-conscious upcycling of sugarcane bagasse into flexible polyurethane foam for mechanical & acoustic relevance.

This study explores the use of sugarcane bagasse (SCB), a byproduct of sugarcane processing, as a bio-filler in the production of flexible polyurethane foam (FPU), focusing on its benefits for both the environment and the economy. By varying the inclusion of SCB waste from 1 to 6 wt%, the research aims to enhance the FPU's mechanical and acoustic characteristics. Techniques such as Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FESEM) were utilized to analyze the chemical structure and surface characteristics of both SCB and the FPU/SCB composites. Additionally, tests on gel fraction, density, and mechanical properties were conducted. The results indicate that adding 4 wt% SCB to FPU considerably improved the foam's properties. This modification resulted in a 148.63% increase in apparent density, a 228.47% rise in compressive strength, and a 116.24% boost in tensile strength. Furthermore, sound absorption across various frequency ranges was enhanced compared to the control foam. Additionally, the findings show that SCB effectively shifts sound absorption characteristics to lower frequencies. Specifically, at a low frequency of 500 Hz, the sound absorption coefficient increased to 0.4 with a foam thickness of 20 mm. This demonstrates that SCB can significantly improve FPU's performance, making it an attractive option for applications requiring noise mitigation, such as in the automotive and construction industries, thereby offering a sustainable solution to waste management and materials innovation.

Current Trends in the Use of Biomass in the Manufacture of Rigid Polyurethane Foams: A Review

This paper discusses methods of using biomass from the agriculture, forestry, food and aquaculture industries as potential raw materials for bio-polyols and as fillers in the production of rigid polyurethane (RPUR) foams. Various aspects of obtaining bio-polyols are discussed, as well as the impact of replacing petrochemical polyols with bio-polyols on the properties of foams. Special attention is paid to the conversion of vegetable oils and lignin. Another important aspect of the research is the use of biomass as foam fillers. Chemical and physical modifications are discussed, and important factors, such as the type and origin of biomass, particle size and amount, affecting the foaming process, microstructure and properties of RPUR foams are identified. The advantages and disadvantages of using biomass in foam production are described. It is found that bio-polyols can replace (at least partially) petrochemical polyols while maintaining the high insulation and strength of foams. In the case of the use of biomass as fillers, it is found that the shaping of their properties is largely dependent on the specific characteristics of the filler particles. This requires further research into process optimization but allows for the fine-tuning of RPUR foam properties to meet specific requirements.

Sound absorption and thermal insulation materials from waste palm oil for housing application: Green polyurethane/water hyacinth fiber sheet composite

This research presents an eco-friendly method for producing polyurethane foam (PUF) and water hyacinth fiber (WHF) sheets. The objectives were to engineer wall materials with sound-absorption and thermal insulation capabilities while also improving the mechanical properties of pure PUF. Waste palm oil (WPO) was successfully utilized as a polyol substrate, playing a substantially role in PUF generation, acting as a PU binder, and serving as a PU adhesive. The productions of PUF (NCO index of 100) combined with WHF sheets (WHF/PU binder ratio of 60/40) using four distinct fabrication methods (sheet-foam-sheet (SFS), foam-sheet-foam (FSF), foam-foam-foam (FFF), and sheet-sheet-sheet (SSS)) were investigated with a fabrication thickness of 150 mm. The findings indicate that the SFS configuration demonstrates remarkable sound absorption properties, with an average sound absorption (SAA) of 0.59, noise reduction coefficient (NRC) of 0.39, and the highest sound absorption coefficient (SAC) of 0.93 at 1900 Hz, alongside a thermal conductivity of 0.0301 W/mK. Importantly, all four methodologies produce SAC values greater than 0.4, outperforming commercial counterparts while demonstrating low thermal conductivity indicative of effective thermal insulation. The result noted that WHF sheet exhibited self-extinguishing properties, making them suitable for use in construction materials. As a result, SFS emerges as the best method for constructing superior sound absorption and thermal insulation materials. This study emphasizes the potential of waste derived WPO and WHF as advantageous eco-friendly substrates for industrial wall and housing materials.

Investigation of bio-based rigid polyurethane foams synthesized with lignin and castor oil

In this study, polyurethane (PU) foams were manufactured using kraft lignin and castor oil as bio-based polyols by replacing 5–20 wt% and 10–100 wt% of conventional polyol, respectively. To investigate the effects of unmodified bio-based polyols on PU foam production, reactivity and morphology within PU composites was analyzed as well as mechanical and thermal properties of the resulting foams. Bio-based PU foam production was carried out after characterizing the reagents used in the foaming process (including hydroxyl group content, molecular weight distribution, and viscosity). To compare the resulting bio-based PU foams, control foam were produced without any bio-based polyol under the same experimental conditions. For lignin-incorporated PU foams, two types, LPU and lpu, were manufactured with index ratio of 1.01 and 1.3, respectively. The compressive strength of LPU foams increased with lignin content from 5 wt% (LPU5: 147 kPa) to 20 wt% (LPU20: 207 kPa), although it remained lower than that of the control foam (PU0: 326 kPa). Similarly, the compressive strength of lpu foams was lower than that of the control foam (pu0: 441 kPa), with values of 164 kPa (lpu5), 163 kPa (lpu10), 167 kPa (lpu15), and 147 kPa (lpu20). At 10 wt% lignin content, both foams (LPU10 and lpu10) exhibited the smallest and most homogenous pore sizes and structures. For castor oil-incorporated PU foams with an index of 1.01, denoted as CPU, increasing castor oil content resulted in larger cell sizes and void fractions, transitioning to an open-cell structure and decreasing the compressive strength of the foams from 284 kPa (CPU10) to 23 kPa (CPU100). Fourier transform infrared (FT-IR) results indicated the formation of characteristic urethane linkages in PU foams and confirmed that bio-based polyols were less reactive with isocyanate compared to traditional polyol. Thermogravimetric analysis (TGA) showed that incorporating lignin and castor oil affected the thermal decomposition behavior. The thermal stability of lignin-incorporated PU foams improved as the lignin content increased with char yields increasing from 11.5 wt% (LPU5) to 15.8 wt% (LPU20) and from 12.4 wt% (lpu5) to 17.5 wt% (lpu20). Conversely, the addition of castor oil resulted in decreased thermal stability, with char yields decreasing from 10.6 wt% (CPU10) to 4.2 wt% (CPU100). This research provides a comprehensive understanding of PU foams incorporating unmodified biomass-derived polyols (lignin and castor oil), suggesting their potential for value-added utilization as bio-based products.

Production, thermal recycling, and application of cardanol-based polyurethane foam with phenol-carbamate bonds

The economic processing, sustainable recycling, and environmentally friendly application of polyurethane (PU) foams are important issues that need to be addressed urgently. In this study, we propose a strategy for the comprehensive utilization of cardanol and cashew shells to design cardanol-based PU (CPU) foams and wood-plastic films that can be recycled and reused. Firstly, cardanol-based polyphenols (CBPs) with a phenolic hydroxyl content of 3.29 mmol/g were prepared by Friedel-Crafts alkylation reaction using cardanol and guaiacol as raw materials. Subsequently, CPU foams were prepared by reacting CBPs with isocyanate, and the vertical and parallel compressive strengths could reach up to 0.27 MPa and 0.32 MPa, respectively, when the addition of CBPs was 80 %. These CPU foams, containing dynamic phenol-carbamate bonds, could be hot-pressed into transparent and smooth CPU films with tensile strengths of up to 30.5 MPa and could be re-formed at least three times. Finally, CPU foam and cashew shell waste were mixed and hot-pressed to produce a green wood-plastic composite with a tensile strength of up to 38.8 MPa. The resulting CPU-Wood films could be repaired or reshaped at least five times (38.0 MPa and 38.1 MPa) and could be formed into various shapes. This research paves the way for large-scale industrial production of recyclable and regenerative bio-based foams, making effective use of waste materials to achieve environmentally friendly production processes.

Phosphorus and nitrogen-containing soybean oil polyols: Effect on the mechanical properties and flame retardancy of polyurethane foam.

In recent years, there has been an increasing interest in producing new materials that use renewable resources and halogen-free flame retardants with nonleaching properties. This research focuses on designing and synthesizing phosphorus-nitrogen-based biopolyols for use in polyurethane (PU) foam production. Polyol (ESBO-DYM) with dual functionalities, renewability, and nonflammability is synthesized through the epoxy ring-opening reaction of epoxidized soybean oil with phosphorus and nitrogen-containing tetraol products (DYM). The mechanical and flame retardant properties of PU foams with the addition of an ESBO-DYM were investigated. Increasing the amount of phosphorus in the PU foams increased the thermal stability properties. Using 100% ESBO-DYM as a polyol in the foam formulation increased the limiting oxygen index (LOI) value to 22.9% and resulted in the highest char yield according to the thermal gravimetric analysis (17% at 600 °C). Additionally, the introduction of ESBO-DYM polyol into the formulation resulted in a decrease in the compression strength of the foams. The foam density decreased as the amount of ESBO-DYM polyol in the formulation increased. The foam with the highest amount of ESBO-DYM had a foam density of 29.1 kg/m3. The morphology of the foams was characterized using a scanning electron microscope (SEM). As a result of this study, flame retardant polyurethane foams were formulated using a renewable source, polyol, along with commercial compounds.

Research on lignin-modified flexible polyurethane foam and its application in sound absorption

Lignin is a sustainable biomass resource with abundant hydroxyl groups that holds great promise for use as a feedstock for polyurethane foam production. Therefore, the flexible polyurethane foams (FPUFs) were prepared using the oxidized alkali lignin (OAL) as the matrix to enhance its compatibility. The OAL was obtained under the following conditions of 60 °C, 80 min treatment, a ratio of hydrogen peroxide to lignin of 1.2:1, and a ratio of iron hydroxide to lignin of 0.01. It was demonstrated that incorporating OAL enhanced the density, compressive strength, sound-absorbing performance and degradability of foam composites. The compressive strength was also improved by more than five times than that of blank foam under the optimal conditions, reaching 0.11 MPa. The thermogravimetric analysis (TGA) revealed that the foam composite containing 30 % modified lignin content exhibited the highest thermal stability. The results of solvent resistance testing demonstrated the durability of the foam composites in both water and solvents. Lignin-modified polyurethane foam exhibited an acoustic absorption coefficient above 0.2 across a wide frequency range, with the highest value reaching 0.84, meeting the conventional requirements for sound absorption materials (α > 0.2). The results suggested that this environmentally friendly preparation method was feasible for producing high-performance polyurethane foams, which was appropriate for the production of sound absorption boards for industry, transportation by train and automobile.

Montmorillonite K10-induced decomposition of methyl N-phenylcarbamate to phenylisocyanate and its prospect for recovering isocyanates from polyurethanes

The significant growth of the production and use of flexible polyurethane (PU) foam causes increased waste accumulation, thereby creating a demand for the recycling of PU. While upgrading PU materials to recycled polyols has been studied in detail, the recovery of diisocyanates is a longstanding challenge. Montmorillonite K10 (MK10) has been proposed as a catalyst to convert carbamates into isocyanates, but its prospects are unclear. Here, the MK10-catalyzed decomposition of methyl phenylcarbamate (MPC) into phenylisocyanate (PI) and the side product N,N’-diphenylurea (DPU) has been studied as a model reaction for the decomposition of PU foam and the potential recovery of PI. The effects of the amount of catalyst, the temperature, and the solvent were investigated by HPLC analyses. Kinetic analysis revealed that the uncatalyzed rate of the MPC decomposition is much lower than the catalyzed rate, indicating that the thermally driven decomposition is negligible. Our results, involving both experimental kinetic studies and models of the kinetics, show that, while MK10 effectively catalyzes the decomposition of MPC, it also causes the formation of aniline, which reacts with PI to form DPU. As a result, large amounts of MK10 favor DPU and prevent the selective formation of PI, and yields of PI >30 % were never observed. Likely, the OH groups of MK10 form covalent bonds with PI, causing a deficiency in the mole balance. Overall, MK10 is unsuited to provide high yields of isocyanates.

Investigating the potential of dihydroxystearic acid as feedstock for rigid polyurethane foam

Rigid polyurethane (PU) foam has been widely used for a multitude of applications, primarily as thermal insulation materials. With the exhortation of “green chemistry” and sustainable development, bio-based polyols are being introduced to replace the conventional petrochemical-based polyols. Hence, the use of 9, 10-dihydroxystearic acid (DHSA), derived from palm oil-based oleic acid, as a feedstock for rigid PU foam production was explored. In this study, the effects of the weight ratio percentage of DHSA on the characteristics of the resulting PU foams were investigated. The DHSA was utilized as a co-polyol to synthesize rigid PU foams by reacting with the diisocyanate compound, blowing agent and additives. In general, the effects of DHSA in the formulations on the quality of the foams were relatively similar to PU formulation without the addition of DHSA, particularly in terms of density, compressive strength, thermal conductivity, cell structure and dimensional stability. The remarkable effect of DHSA addition in the PU formulations was observed through the open PU cell content using a pycnometer and scanning electron microscopy (SEM). The addition of DHSA has the ability to open the cell structure of the resulting rigid PU foams. The open cell content increased notably from 6.83% to 90.99% when the DHSA content was increased from 0% to 50%. The ability of DHSA to produce open-cell rigid PU foam widens up the potential applications of rigid PU foams as sound absorption materials.

Acid-catalyzed Kraft lignin liquefaction for producing polyols and polyurethane foams

This study investigates the use of acid-catalyzed lignin liquefaction for the production of polyols and polyurethane foams. The liquefaction process was carried out using a kraft lignin powder following a process similar to the Lignoboost® method, based on a previous study, with catalyst (sulfuric acid) weight contents of 0, 3 and 6 wt.% in relation to the lignin. The PU foams were prepared by the free expansion method and analyzed by Fourier transform infrared spectroscopy (FT–IR), thermogravimetry (TG), differential scanning calorimetry (DSC), dynamic-mechanical analysis (DMA), as well as contact angle and apparent density evaluations. The effect of the catalyst concentration on yield, moisture content and molecular weight of the resulting polyols was assessed, and the optimal conditions were obtained for 6 wt.%. FT–IR analysis indicated a suitable foam polymerization. The incorporation of an acid catalyst led to a more hydrophilic foam and a rigid cell structure, with thinner and more uniformly sized cells, as well as higher thermal stability and glass transition temperature.

Analysis of Polyurethane Foam Machining Parameter Influence: Current Status and Perspective

Nowadays, polyurethane (PU) foam has successfully replaced various engineering materials in many applications due to its many advantages in mechanical and thermal properties. In various applications, PU foam must be formed into various 3-dimensional models according to user requirements by utilizing CAM software and CNC milling machining to manufacture a product. Thus, the selection of cutting parameters in the milling machining process in terms of the nature and character of the material and cutting tools is essential and significantly influences the geometric structure and surface roughness of the PU foam products produced. Based on the review of this article, several machining parameters must be appropriately considered, including spindle rotation speed, depth of cut, cutting tool selection, and feed rate. Vibration will increase as the spindle rotation speed increases, which brings cutting tools but results in better surface quality. Continuous chip formation can be achieved by selecting the proper cut depth and producing low surface roughness values. Selecting suitable cutting tools and geometries that match the material characteristics can reduce the risk of material damage during the machining process, thereby reducing the surface roughness value. Finally, a low cutting rate will minimize surface roughness but increase the risk of cutting-edge wear.

Fractionated lignin as a polyol in polyurethane fabrication

The main purpose of this paper was to systematically evaluate the effect of lignin, which was fractioned by green solvents into different molecular weights and used as polyol in the production of polyurethane foams (PUF). The results indicated that the foams prepared with the lower molecular weight lignin had uniform and complete pore structure and improved the mechanical strength. However, the higher molecular weight fraction lignin improved the density and thermal stability of the foam more significantly at the expense of inferior mechanical strength and pore structure deficiency. When the substitution degree of lignin in the PUF was 2 %–30 %, 99.13 % of the lowest molecular weight lignin was participated in the reaction to produce PUF, which improved the elongation at break (Eb) and tensile strength (Ts) of PUF to 834 % and 0.90 MPa, respectively. Also, thermal stability and the amount of unreacted lignin in PUF were increased at a higher substitution degree of lignin in PUF.

Green synthesis of chitin/lignin based-polyurethane composites

Polyurethanes (PU) are still among the most promising high-performance materials in industrial applications. Nevertheless, the development of sustainable and efficient materials is an ongoing challenge for the plastics industry. In recent years there has been growing interest in utilizing natural materials such as chitin and lignin as additives in polyurethane foam production. This study focuses on the utilization of sustainable chitin–lignin filler for polyurethanes with the aim of producing sustainable, cost-effective, and efficient foam materials. A chitin–lignin filler was prepared using a mechanochemical approach, and flexible polyurethane foams (FPUFs) were synthesized with varying amounts of chitin–lignin additive. The resulting foams were characterized using various analytical techniques, including scanning electron microscopy, compression testing, tensile strength analysis, and measurements of surface free energy and contact angle. Possible interactions between the filler and PU were analyzed by means of FTIR spectroscopy. The results show that the addition of chitin–lignin filler improved the mechanical properties (in comparison to pristine chitin and lignin as filler), with a significant reduction in the compression set of the polyurethane foams, a crucial property in the production of seat foams. Synergy was observed between chitin–lignin filler in PU foam. Overall, the study demonstrates the potential of chitin–lignin as a sustainable and efficient natural filler that can be effectively applied on the industrial scale. The combination of these two biopolymers led to a polyurethane composite with better mechanical properties. Additionally, the use of biopolymers (chitin and lignin) as a filler for FPUFs is one of the options for the management of waste materials, which is in line with the idea of sustainable production.

Preparation and Effect of Methyl-Oleate-Based Polyol on the Properties of Rigid Polyurethane Foams as Potential Thermal Insulation Material.

Recently, most of the commercial polyols used in the production of rigid polyurethane foams (RPUFs) have been derived from petrochemicals. Therefore, the introduction of modified palm oil derivatives-based polyol as a renewable material into the formulation of RPUFs is the focus of this study. A palm oil derivative-namely, methyl oleate (MO)-was successfully modified through three steps of reactions: epoxidation reaction, ring-opened with glycerol, followed by amidation reaction to produce a bio-based polyol named alkanolamide polyol. Physicochemical properties of the alkanolamide polyol were analyzed. The hydroxyl value of alkanolamide polyol was 313 mg KOH/g, which is suitable for producing RPUFs. Therefore, RPUFs were produced by replacing petrochemical polyol with alkanolamide polyol. The effects of alkanolamide polyol on the physical, mechanical and thermal properties were evaluated. The results showed that the apparent density and compressive strength increased, and cell size decreased, upon introducing alkanolamide polyol. All the RPUFs exhibited low water absorption and excellent dimensional stability. The RPUFs made with increased amounts of alkanolamide polyol showed higher thermal conductivity. Nevertheless, the thermal conductivities of RPUFs made with alkanolamide polyol are still within the range for thermal insulating materials (<0.1 W/m.K). The thermal stability of RPUFs was improved with the addition of alkanolamide polyol into the system. Thus, the RPUFs made from alkanolamide polyol are potential candidates to be used as insulation for refrigerators or freezers.

Development of a Laboratory-Scale Steam Boiler for Polyurethane (Foam) Waste Recycling Machine

In this paper, a laboratory-scale (small) Steam Boiler was designed and developed for a small-scale polyurethane recycling machine. A small-sized polyurethane machine was developed for the recycling of polyurethane foams to reduce wastes in the polyurethane production industries and also to reuse old discarded foams after their useful lives. It has been observed from studies carried out in many foam manufacturing industries that the polyurethane foam wastes generated from various plant operations are enormous. Also, polyurethane (foam) products are everywhere in our homes, industries and automobiles and are always discarded after their useful lives. These wastes need to be recycled always in other for them not to get back into our ecosystems thereby polluting our environment because polyurethane foams are non-biodegradables and can remain in the environment for a very long time. However, only a few companies with strong financial capabilities are able to embark on this venture because of the high costs of machinery and large quantities of chemicals involved. The high costs of machinery and chemicals also deter cottage industries from participating in the recycling of old and discarded polyurethane foams. Therefore, there is a need to develop small-scale polyurethane foam waste recycling machines to reduce the costs of machinery and chemicals involved in the recycling thereby allowing more participation in the recycling process. The boiler is used to generate high-temperature steam for curing and better bonding of the shredded foams. The heating chamber of the machine consists of the steam boiler, and pressure hose to enable passage of steam from the steam boiler into the molding box. The total volume of the boiler is 2.5 Litres. The outlet steam temperature is 135 0C and 25 psi pressure. The heat rate is 1.52 kJ/s. The recycled foams were able to cure and bonded better with the addition of steam compared to without the steam. The percentage difference in I.F.D, Resilience, Tensile Stress and percent elongation are +0.56, -2.00, +85.45, and +68.39 respectively. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

New approach to recycle and valorize the first filtrate of the LignoForce system™: Lignin extraction and its use in rigid lignin-based polyurethane foams

In this work, we report on the fractionation, recovery and characterization of softwood kraft lignin from the first filtrate of the LignoForce™ process. It is estimated that the lignin content in this stream could be >20–30 % of the lignin present initially in the black liquor. The use of a membrane filtration system was experimentally validated as an effective method for fractionating the first filtrate. Two membranes with different nominal molecular weight cut-offs (4000 and 250 Da) were tested. Higher lignin retention and recovery was obtained using the 250-Da membrane. This lignin (lignin_250) was found also to have a lower molecular weight and a tighter molecular weight distribution compared to the lignin obtained using the 4000-Da membrane (lignin_4000). The lignin_250 was characterized for it's hydroxyl group content and used to produce polyurethane (PU) foams. Up to 30 wt% petroleum-based polyol replacement by lignin_250, the resulting lignin-based PU (LBPU) foams presented the same thermal conductivity as the control (0.0303 W/m.K (control) vs 0.029 W/m.K (30 wt%)), as well as comparable mechanical (max stress: 145.8 kPa (control) vs 222.7 KPa (30 wt%), modulus 64.3 kPa (control) vs 75.1 (30 wt%)) and morphological properties to the petroleum polyol-based PU foams.

Polyurethane Recycling: Thermal Decomposition of 1,3-Diphenyl Urea to Isocyanates.

Substituted urea linkages are formed during the production of polyurethane foam. To chemically recycle polyurethane toward its key monomers via depolymerization (i.e., isocyanate), it is essential to break the urea linkages to form the corresponding monomers, namely, an isocyanate and an amine. This work reports the thermal cracking of a model urea compound (1,3-diphenyl urea, DPU) into phenyl isocyanate and aniline in a flow reactor at different temperatures. Experiments were performed at 350-450 °C, with a continuous feed of a solution of 1 wt.% DPU in GVL. In the temperature range studied, high conversion levels of DPU are achieved (70-90 mol%), with high selectivity towards the desired products (close to 100 mol%) and high average mole balance (∼95 mol%) in all cases.

Reticulated effectiveness assessment of polyurethane form in the melting process with deflagration method

The flexible polyurethane foam (FPUF) is widely used in the impact damping, noise insulation and other fields because of its good mechanical properties and porous structure. Unlike the previous methods, deflagration method can effectively remove partial original membrane while preserving skeleton structure, and is an environmentally friendly treatment process, representing an efficient and simple operation technology. Combustible premixed gas (CPG) is vital for deflagration process and can determine the reticulated effectiveness of polyurethane foam. The research purpose of this paper is to study the effect of the combustible premixed gas (CPG) parameters (the inflation coefficient, gas type and gas concentration) on the open porosity index of the polyurethane film through modeling and simulation methods. Based on the established mode, the paper uses the standard k-ε model coupling with the melting-solidification model based on the enthalpy-porosity method. The numerical simulation results demonstrate good agreement with the experimental data. The external surface center temperature (ESCT) is probably not constant but increases with the inflation coefficient. The analysis demonstrates that inflation coefficient significantly affects the concentration of CPG. Since the calorific value of combustible gas is limiting, a suitable union of inflation coefficient and concentration would provide better utilization of the method. Combustible gas with high calorific value were able to achieve an average open porosity promotion 0.275 within the inflation coefficient rage from 1 to 5. The approach adopted allows to provide heoretical basis for the efficient and standardized production of flexible polyurethane foam.

Effects of additives on properties of self-skinning polyurethane foam for automobile steering wheel

Commercialized polyurethane foam products for automobile steering wheels have been committed to the development of products with comprehensive properties such as low density, high production efficiency and environmental protection. Based on this, this article has launched a series of experiments to explore the effects of different types of chain extenders, blowing agents and catalysts on the mechanical properties, cell structure, skin and reactivity of self-skinning polyurethane foams for automobile steering wheels. The results show that the hardness and tensile strength of the foam gradually decrease with the chain growth of small molecular chain extenders (ethylene glycol, 1.3-propanediol, 1.4-butanediol), and the elongation at break increases gradually. The foaming agent formic acid is more conducive than water as it favors the formation of small but compact cells, thus dense skin. The catalytic efficiency of non-reactive catalysts (A1, KC101 and DabcoEG) is higher than that of reactive catalysts (LED-103, ZR-50, DPA). The theoretical research for the development of high-performance and high-efficiency polyurethane foam products for automobile steering wheels.