Anhydride Hardener Research Articles

Rapid tooling for rubber extrusion molding by digital light processing 3D printing with dual curable vitrimers

AbstractFor the manufacture of extrusion dies, three‐dimensional (3D) printing with photopolymers offers numerous advantages including flexibility, high surface quality, decent build speed, low costs and a reduced amount of waste. However, the majority of photocurable resins used in vat photopolymerization 3D printing rely on acrylates, which entail 3D‐printed objects with poor mechanical properties. In particular, the high brittleness limits their application in rapid tooling, for which tough materials with high glass transition temperatures (Tg) are required. In the present study, we highlight the use of dual curable acrylate‐epoxy resins with dynamic covalent bonds for the direct fabrication of extrusion dies. During digital light processing (DLP) 3D printing the acrylate network is formed, whose toughness and thermal stability are significantly enhanced by the thermoactivated formation of a second network. By following a postbaking procedure, aminoglycidiyl monomers are cured with an anhydride hardener bearing bulky norbornene groups yielding interpenetrating polymer networks with a Tg > 100°C. The tertiary amine groups present in the structure of the aminoglycidyl derivatives do not only accelerate the ring‐opening reaction but also act as internal catalysts and activate bond exchange reactions between free –OH groups and ester moieties available in the photopolymer. This is confirmed by rheometer studies showing a distinctive stress relaxation at elevated temperature and giving rise to a possible reprocessability of the 3D‐printed dies. With a selected resin formulation, a set of dies is printed by DLP 3D printing, with which a highly filled rubber compound is successfully extruded. The results clearly show that dual curable resins with dynamic covalent bonds are a promising class of material for rapid tooling and pave the way towards a customized and convenient fabrication of extrusion dies for rubber processing.

Curing kinetics study of chemically modified pineapple leaf fiber/epoxy composite

Agricultural by-products have long hinder farmers, and subsequently, the food supply chain. Making use of their natural by-products will both reduce waste and increase industrial production. In particular, pineapple leaf fibers (PALF) can be extensively studied. Here, the curing kinetics of chemically modified PALF/epoxy resin crosslinked by an anhydride hardener was investigated by non-isothermal and isothermal methods with the differential scanning calorimetry technique. In this study, the Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa methods, as well as Kamal's model, were employed to analyze the curing behavior of epoxy in non-isothermal and isothermal processes, respectively. The highest activation energies for pure epoxy and PALF/epoxy composite calculated differ when using the methods. Additionally, a decreasing trend in the activation energy values during the late stages of epoxy curing was observed. The results from Kamal's model indicate that the k1 values of the PALF/epoxy composite are only greater than those of pure epoxy at 100°C and 110°C. However, all the k2 values of PALF/epoxy are greater than those of pure epoxy. Additionally, the m value of the PALF/epoxy composite is lower than that of pure epoxy only at 100°C, while the n and m+n values of the PALF/epoxy composite are all greater than those of pure epoxy. Moreover, the results reveal that the Cure Index of the PALF/epoxy composite was larger than ΔH* and smaller than ΔT*. With PALF, it was found that the epoxy resin’s curing rate was increased and the activation energy was reduced. Meanwhile, the degree of crosslinks was less than that of the virgin resin. It is speculated that the hydroxyl groups on the plant fibers and the amine groups on the coupling agent-modified fibers can promote the cross-linking reaction. However, the curing reaction of the composite is affected by steric obstacles and high viscosity resulting from the addition of PALFs.

Reinforced Epoxy Binder Modified with Borpolymer.

Polymer binders based on epoxy resins have unique properties that contribute to their use in many composite industries. The potential of using epoxy binders is due to their high elasticity and strength characteristics, thermal and chemical resistance, and resistance to climatic aging. This is the reason for the existing practical interest in modifying the composition of epoxy binders and understanding the strengthening mechanisms in order to form reinforced composite materials with a required set of properties based on them. This article presents the results of a study of the process of dissolving the modifying additive of polymethylene-p-triphenyl ether of boric acid in the components of an epoxyanhydride binder applicable to the production of fibrous composite materials. The temperature and time conditions for the dissolution of polymethylene-p-triphenyl ether of boric acid in anhydride-type isomethyltetrahydrophthalic anhydride hardeners are presented. It has been established that the complete dissolution of the borpolymer-modifying additive in iso-MTHPA occurs at a temperature of 55 ± 2 °C for 20 h. The effect of the modifying additive of polymethylene-p-triphenyl ether of boric acid on the strength properties and structure of the epoxyanhydride binder has been studied. Increases in transverse bending strength up to 190 MPa, elastic modulus up to 3200 MPa, tensile strength up to 0.8 MPa, and impact strength (Charpy) up to 5.1 kJ/m2 are observed when the content of the borpolymer-modifying additive in the composition of the epoxy binder is 0.50 mass. %.

Epoxidized and Maleinized Hemp Oil to Develop Fully Bio-Based Epoxy Resin Based on Anhydride Hardeners

The present work aims to develop thermosetting resins using epoxidized hemp oil (EHO) as a bio-based epoxy matrix and a mixture of methyl nadic anhydride (MNA) and maleinized hemp oil (MHO) in different ratios as hardeners. The results show that the mixture with only MNA as a hardener is characterized by high stiffness and brittleness. In addition, this material is characterized by a high curing time of around 170 min. On the other hand, as the MHO content in the resin increases, the mechanical strength properties decrease and the ductile properties increase. Therefore, it can be stated that the presence of MHO confers flexible properties to the mixtures. In this case, it was determined that the thermosetting resin with balanced properties and high bio-based content contains 25% MHO and 75% MNA. Specifically, this mixture obtained a 180% higher impact energy absorption and a 195% lower Young's modulus than the sample with 100% MNA. Also, it has been observed that this mixture has significantly shorter times than the mixture containing 100% MNA (around 78 min), which is of great concern at an industrial level. Therefore, thermosetting resins with different mechanical and thermal properties can be obtained by varying the MHO and MNA content.

Alkali resistant epoxy binders for pultrusion

Alkali-resistant hot-curing epoxy binders based on ED-20 and new amine hardeners “Amikrost” have been developed, intended for the production of glass-composite fittings for construction purposes. The rheological properties of epoxy compositions were determined, using differential scanning calorimetry and thermogravimetric analysis, the temperature dynamics of the curing process of epoxy compositions and the thermal-oxidative resistance of cured samples were studied. The alkali resistance of cured epoxy compositions and specimens of composite reinforcement in 40% alkali aqueous solution was evaluated. It is shown that the developed amine hardeners provide high alkali resistance of composite reinforcement in comparison with the currently used anhydride hardener iso-MTHPA, which is especially important for reinforcing buried and hydraulic concrete.

ВЛИЯНИЕ КОМПОНЕНТНОГО СОСТАВА НА УДАРНУЮ ВЯЗКОСТЬ ОТВЕРЖДЕННОГО ПОЛИМАТРИЧНОГО СВЯЗУЮЩЕГО

The design of products made of polymer composite materials involves constant work on optimizing the component composition, leading to a reduction in the cost of manufacturing PCM while maintaining or improving operational characteristics. The epoxy-diane binder used in the production of products is an expensive component. In order to reduce the cost of the finished product, the authors proposed to develop a polymatric material by replacing part of the epoxy-diane binder with polyester. Reducing the cost of the material, expanding the list of useful properties, reducing density, increasing strength characteristics – this is not a complete list of positive moments when creating a hybrid (polymatric) material, including when creating polymatric structures. The authors of this article analyzed poly-matrix structures based on epoxy-diane and polyester binders. A polymatric material based on EDI (on an anhydride hardener) with a polyester resin was selected as the object of the study, tert-butyl peroxybenzoate was used as a hardener to which. As an indicator of evaluating the effectiveness of the polymatric binder, the impact strength was chosen as the most sensitive characteristic to structural changes at the level of the chemical mesh and the degree of curing. The analysis of experimental data made it possible to derive a correlation equation that allows theoretically calculating the final result for the impact strength of a polymatric material, taking into account the volume fraction of the substituent – polyester resin. Based on the results of the study, re­commendations on the use of this dependence are given. The article summarizes the authors' experience and requires further study.

Solid Particle Erosion of Filled and Unfilled Epoxy Resin at Room and Elevated Temperatures

Solid particle erosion at room and elevated temperatures of filled and unfilled hot-cured epoxy resin using an anhydride hardener were experimentally tested using an accelerated method on a special bench. Micro-sized dispersed industrial wastes were used as fillers: fly ash from a power plant and spent filling material from a copper mining and processing plant. The results showed that the wear of unfilled epoxy resin significantly decreases with increasing temperature, while the dependence on the temperature of the wear intensity at an impingement angle of 45° is linear and inversely proportional, and at an angle of 90°, non-linear. The decrease in wear intensity is probably due to an increase in the fracture limit because of heating. Solid particle erosion of the filled epoxy compounds is considerably higher than that of unfilled compounds at impingement angles of 45° and 90°. Filled compounds showed ambiguous dependences of the intensity of wear on temperature (especially at an impingement angle of 45°), probably as the dependence is defined by the filler share and the structural features of the samples caused by the distribution of filler particles. The intensity of the wear of the compounds at impingement angles of 45° and 90° has a direct and strong correlation with the density and the modulus of elasticity, and a weak correlation with the bending strength of the materials. The data set for determining the correlation between the mechanical properties and the wear included compound filling characteristics and temperature.

Study of rheological and physical-mechanical properties of epoxy systems with curing agents of different nature

Rheological and physicomechanical properties of epoxy binders based on ED-20 epoxy resin with isoMTHPA and HT-152B (modified isoMTHPA) anhydride hardeners and of a binder based on Ethal-370 modified epoxy resin with Ethal-450 amine hardener have been studied. The pot life of the binders based on ED-20 and anhydride curing agents (isoMTHPA and HT-152B) at 25 °С is quite high. The binders based on Etal-370 and Etal-450 must be preheated before use to 40-60 °C due to the high viscosity. The highest strength of 57.3 MPa was achieved for the composite based on ED-20 and HT-152B.

Effect of Dielectric Relaxation of Epoxy Resin on Dielectric Loss of Medium-Frequency Transformer

Epoxy resin (EP) is a typical and widely used insulating material for medium-frequency transformers (MFTs). The dielectric loss of EP is one of the key variables in the design and operation of MFT. In this article, six types of epoxy/anhydride systems are prepared, and the dielectric loss of MFT is calculated by finite element method (FEM) analysis based on broadband dielectric spectroscopy measurements. The material dependence of the dielectric loss of MFT is investigated using dielectric spectroscopy and molecular dynamics simulations over a wide temperature and frequency range. The results show that the variation of dielectric loss with output power is attributed to the temperature characteristics of the imaginary part ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon ^{\prime \prime }$ </tex-math></inline-formula> ) of complex permittivity. Compared to the dielectric loss at no-load state, the one at rated power is reduced by 5–10 W. The anhydride hardener containing benzene ring or a methyl substituent has an inhibitory effect on dielectric loss, and the EP cured by methyl nadic anhydride (MeNA) has the lowest dielectric loss (16.2 W) at rated power. The dielectric loss and overload characteristics of MFT are closely related to the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -relaxation and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\alpha $ </tex-math></inline-formula> -relaxation of EP, respectively. The acid anhydride curing agent containing benzene ring or a methyl substituent reduces the temperature corresponding to the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -relaxation peak by more than 50 °C compared to the one without. The increased rigidity of the chain segment of EP makes the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -relaxation move to the low-temperature side, which is beneficial to suppress the dielectric loss. This article not only serves as a bridge among dielectric loss of MFT, dielectric spectroscopy, and molecular structure of EP but also lays a solid foundation for the selection of insulating materials for MFT.

Effect of Long-Term Thermal Relaxation of Epoxy Binder on Thermoelasticity of Fiberglass Plastics: Multiscale Modeling and Experiments.

The work is devoted to the prediction and experimental research of the elastic bending modulus of glass-reinforced plastics with an epoxy matrix on anhydride hardener reinforced with different glass fabrics. Experimental studies have been carried out to assess the effect of thermal relaxation of the polymer matrix structure due to long-term exposure to elevated temperatures (above the glass transition temperature of the polymer matrix) on the GRP elastic bending modulus at temperatures ranging from 25 to 180 °C. It has been shown that due to the thermal relaxation of the polymer matrix structure, the GRP modulus increases significantly at temperatures above 110 °C and decreases slightly at lower temperatures. Using a multiscale simulation based on a combination of the finite-element homogenization method in the Material Designer module of the ANSYS software package and three-point bending simulation in the ANSYS APDL module, the elastic modulus of FRP was predicted concerning the temperature, its averaged structural properties, and thermal relaxation of the polymer matrix structure. We have also carried out the prediction of the temperature dependences of the modulus of elasticity of glass-reinforced plastics on different types of glass fabrics in the range from 25 to 200 °C by using the entropic approach and the layered model.

Influence of Different Kinds of Plant Fibers on the Curing Kinetics of Epoxy Resin

The curing kinetics of the epoxy resin crosslinked by an anhydride hardener with and without plant fibers was investigated. The epoxy composites containing modified pineapple leaf fiber (EASF), banana fiber (EBSF), and bamboo chopsticks fibers (ECSF) were analyzed by non-isothermal differential scanning calorimetry (DSC) technique. Dynamic methods were used to predict the total heat of reaction of the epoxy resin and its activation energy based on the methods of Kissinger and Ozawa. The results showed that, at a low heating rate (5 °C/min), the ΔH of the pure epoxy, EASF, EBSF, and ECSF were 326.2, 307.6, 295.6, and 366.6 J/g, respectively. The curing rate increased, and the activation energy was decreased due to the catalytic role of hydroxyl groups of plant fibers. Based on Kissinger and Ozawa methods, the calculation of activation energy for pure epoxy was 70.08 kJ/mol and 73.21 kJ/mol, EBSF was 68.07 kJ/mol and 71.41 kJ/mol, ECSF was 60.11 kJ/mol and 63.87 kJ/mol, and EASF was 58.71 kJ/mol and 62.49 kJ/mol. The activation energy for the three kinds of epoxy composite modified fibers was less than pure epoxy resin due to the gel effect resulting from the higher viscosity, faster curing rate, and steric hindrance.

Cross-Linking and Evaluation of the Thermo-Mechanical Behavior of Epoxy Based Poly(ionic Liquid) Thermosets.

Poly(ionic liquids) (PILs) and ionenes are polymers containing ionic groups in their repeating units. The unique properties of these polymers render them as interesting candidates for a variety of applications, such as gas separation membranes and polyelectrolytes. Due to the vast number of possible structures, numerous synthesis protocols to produce monomers with different functional groups for task-specific PILs are reported in literature. A difunctional epoxy-IL resin was synthesized and cured with multifunctional amine and anhydride hardeners and the thermal and thermomechanical properties of the networks were assessed via differential scanning calorimetry and dynamic mechanical analysis. By the selection of suitable hardeners, the glass transition onset temperature (Tg,onset) of the resulting networks was varied between 18 °C and 99 °C. Copolymerization of epoxy-IL with diglycidyl ether of bisphenol A (DGEBA) led to a further increase of the Tg,onset. The results demonstrate the potential of epoxy chemistry for tailorable PIL networks, where the hardener takes the place of the ligands without requiring an additional synthesis step and can be chosen from a broad range of commercially available compounds.

다층 적층 나노복합체의 마찰학적 특성 비교 연구

Wear resistance studies for the multilayer laminate nanocomposite experimentally need a lot of time and money to investigate the effects of different parameters over it. Furthermore, the impact of these parameters on the surface occurs within a microsecond making the investigation very difficult. Statistical methods such as response surface methodology can be an effective technique in this matter. In the current work, the response surface methodology and the artificial neural network were used to design and analyze the weight loss at different temperatures, sliding speeds, applied loads, and weight percentages of graphene nanoplatelet (GNP) for multilayers laminate composite consists of polyurethane resin and anhydride hardener reinforced with 30 volume fraction of random fiber-glass. It was found that increasing GNP content could effectively increase friction coefficient and reduce the wear rate of multilayer laminate nanocomposite. The predicted values from artificial neural networks and experimental methods are found very close to each other.

The impact of water released from boehmite nanoparticles during curing in epoxy‐based nanocomposites

AbstractThe enhancing effect on mechanical properties of boehmite (γ‐AlOOH) nanoparticles (BNP) in epoxy‐based nanocomposites on the macroscopic scale encouraged recent research to investigate the micro‐ and nanoscopic properties. Several studies presented different aspects relatable to an alteration of the epoxy polymer network formation by the BNP with need for further experiments to identify the mode of action. With FTIR‐spectroscopic methods this study identifies interactions of the BNP with the epoxy polymer matrix during the curing process as well as in the cured nanocomposite. The data reveals that not the BNP themselves, but the water released from them strongly influences the curing process by hydrolysis of the anhydride hardener or protonation of the amine accelerator. The changes of the curing processes are discussed in detail. The changes of the curing processes enable new explanation for the changed material properties by BNP discussed in recent research like a lowered glass transition temperature region (Tg) and an interphase formation.

Characterization of nano-additive filled epoxy resin composites (ERC) for high voltage gas insulated switchgear (GIS) applications

Abstract Insulation based on epoxy resin (ER) is widely used for high voltage and high fault current rated electrical substation equipment. This paper details the formulation of epoxy based Nano-composites and influence of the Nano filler material on the electrical and thermal properties like breakdown voltage (BDV), relative permittivity, tanδ and thermal conductivity of the epoxy resin composites (ERC). The nano-filler materials such as alumina (Al2O3), silica (SiO2) and titania (TiO2) are considered for the study. Diglycidyl ether of biphenyl-A (DGEBA) type epoxy resin CY5950 and acid anhydride hardener HY5951 are used for development of samples/insulated spacers. Scanning electron microscopy (SEM) images have been established for various ER composites to understand how the dispersion of nano-filler material influences the performance parameters of the samples. In the present study, the sample preparation with metallic inserts has shown additional advantages compared to existing practice of purely insulated samples. Developed samples help to estimate electrical and mechanical properties more accurately. Most appropriate nano filler is identified based on the test results obtained on samples developed in the study. Finally, by using the identified epoxy–filler composite, insulated spacers for 145 kV GIS have been developed and evaluated for electro-mechanical parameters. Necessary dielectric tests have been carried out on developed insulated spacer as per IEC.

An application of Taguchi method for fabrication factors optimisation of banyan aerial root fibre reinforced polymer composite

ABSTRACT Composite materials have always attracted interest from researchers as well as end-users at the same time, due to its flexibility and low cost. Our present study deals with the possible usage of natural fibres extracted from the banyan tree (Ficus Benghalensis) for engineering applications. Epoxy resin (Araldite LY 556) and anhydride hardener (HY 917) are used as the matrix to fabricate the composite panel. In this research work, 30% of fibre derived from banyan aerial root has been reinforced with 70% of polymer mat to study for its mechanical properties such as tensile strength and flexural strength. The processing of the composite materials is done by hand layup process at room temperature. Later specimens are cut from the prepared composite laminates according to the ASTM 3039 (tensile) and ASTM D790 (flexural) Standards. Finally, the Fractography of the mechanically tested specimens was analysed using FESEM.

Improving Adhesion between Epoxy Adhesive Compositions and Aluminum Using Epoxy- and Amino-Alkoxysilane Promoters

Two ways of using 3-glycidoxy propyltrimethoxycilane and 3-aminopropyltriethoxysilane promoters for improving adhesion between epoxy adhesive compositions cured using anhydride and amine hardeners and D16AT aluminum alloy are considered. The work of adhesion and free surface energy of epoxy adhesive compositions with promoters are determined. The possible reactions of the promoters to the components of the adhesive compositions and a metal surface are studied. A probable mechanism of bonding epoxy adhesives and a substrate is proposed. It is shown that preliminary treatment of the aluminum alloy surface with an aqueous alcohol solution of a promoter is the most effective way to increase adhesive shear strength.

Thermal and Fire Behavior of a Bio-Based Epoxy/Silica Hybrid Cured with Methyl Nadic Anhydride.

Thermosetting polymers have been widely used in many industrial applications as adhesives, coatings and laminated materials, among others. Recently, bisphenol A (BPA) has been banned as raw material for polymeric products, due to its harmful impact on human health. On the other hand, the use of aromatic amines as curing agents confers excellent thermal, mechanical and flame retardant properties to the final product, although they are toxic and subject to governmental restrictions. In this context, sugar-derived diepoxy monomers and anhydrides represent a sustainable greener alternative to BPA and aromatic amines. Herein, we report an “in-situ” sol–gel synthesis, using as precursors tetraethylorthosilicate (TEOS) and aminopropyl triethoxysilane (APTS) to obtain bio-based epoxy/silica composites; in a first step, the APTS was left to react with 2,5-bis[(oxyran-2-ylmethoxy)methyl]furan (BOMF) or diglycidyl ether of bisphenol A (DGEBA)monomers, and silica particles were generated in the epoxy in a second step; both systems were cured with methyl nadic anhydride (MNA). Morphological investigation of the composites through transmission electron microscopy (TEM) demonstrated that the hybrid strategy allows a very fine distribution of silica nanoparticles (at nanometric level) to be achieved within a hybrid network structure for both the diepoxy monomers. Concerning the fire behavior, as assessed in vertical flame spread tests, the use of anhydride curing agent prevented melt dripping phenomena and provided high char-forming character to the bio-based epoxy systems and their phenyl analog. In addition, forced combustion tests showed that the use of anhydride hardener instead of aliphatic polyamine results in a remarkable decrease of heat release rate. An overall decrease of the smoke parameters, which is highly desirable in a context of greater fire safety was observed in the case of BOMF/MNA system. The experimental results suggest that the effect of silica nanoparticles on fire behavior appears to be related to their dispersion degree.

Nanocomposites of epoxidized soybean oil (ESO)-based epoxy (DGEBA) blends and clay platelets: cured with methylhexahydrophthalic anhydride crosslinker

The effect of Closite C93A nanoclay on the mechanical, thermal properties of diglycidyl ether bisphenol A (DGEBA) epoxy resin and epoxidized soybean oil (ESO) bioepoxy blend at various wt.% (10, 20, 30) cured with anhydride hardener (MHHPA) existence of 2-methylimidazole (2-MI) as an accelerator was investigated. The DGEBA/ESO blend systems optimized through the mechanical properties. The 20 wt.% DGEBA/ESO blend systems exhibited higher tensile and impact strength incorporation of 0.5–2.5 wt.% C93A nanoclay. The curing reaction of DGEBA blends and its nanocomposites with MHHPA, 2-MI was explored by non-isothermal differential scanning calorimetry (DSC). The thermal stability of DGEBA/20%ESO blend enhanced by loading of 2.5 wt.% C93A nanoclay which restrict the flexibility of chain and obstructed the decomposition process. The formation of exfoliated inside the clays in the DGEBA/ESO/2.5%C93A nanocomposites corroborated by X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis.

Biobased structural epoxy foams derived from plant-oil: Formulation, manufacturing and characterization

This paper is devoted to the description of the scientific method used for developing biobased structural foams derived from highly reactive epoxy resins. The chemical formulations were obtained from the mixing of two epoxidized plant oil-derivates (epoxidized linseed oil ELO and glycerol triglycidyl ether commonly named epoxidized glycerol EG) with an anhydride hardener and a non-toxic foaming agent. The optimization of the composition was achieved by studying the influence of many parameters such as the proportion of each epoxy molecule in the reactive formulation, the exact nature of the hardener or foaming agent retained by the use of different complementary experimental techniques. For instance, the reactivity of four cyclic anhydride compounds with ELO was investigated by differential scanning calorimetry and rheometry in dynamic or kinetic mode. Two different blowing agents were initially retained for the preparation of foams and their respective density and mechanical properties were evaluated and compared. The proportion of each epoxy molecule (ELO and EG) was also tuned to achieve a good equilibrium between the gelation and foaming mechanisms within a few minutes. The definition of an optimized composition made it possible the production of rigid foams using a short production time (i.e. lower than 3 min). These foams were characterized by a glass transition temperature close higher than 80 °C and an apparent density comprised between 0.05 and 0.08 g/cm3. Their specific mechanical properties were judged convenient for a possible valorisation as lightweight structural material.