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The melt strength of Elium® acrylic resin is an important factor to ensure limited fluid flow during welding. To provide Elium® with a suitable melt strength via a slight crosslink, this study examines the effect of two dimethacrylates, namely butanediol-di-methacrylate (BDDMA) and tricyclo-decane-dimethanol-di-methacrylate (TCDDMDA), on the weldability of acrylic-based glass fibre composites. The resin system impregnating a five-layer woven glass preform is a mixture of Elium® acrylic resin, an initiator, and each of the multifunctional methacrylate monomers in the range of 0 to 2 parts per hundred resin (phr). Composite plates are manufactured by vacuum infusion (VI) at an ambient temperature and welded by using the infrared (IR) welding technique. The mechanical thermal analysis of the composites containing multifunctional methacrylate monomers higher than 0.25 phr shows a very little strain for the temperature range of 50 °C to 220 °C. The quantity of 0.25 phr of both of the multifunctional methacrylate monomers in the Elium® matrix improves the maximum bound shear strength of the weld by 50% compared to those compositions without the multifunctional methacrylate monomers.

Fusion assembly is a highly promising technique to join thermoplas- tic to thermoset composites, enabling the use of both the most affordable com- posite material and process for each sub structure.Yet, some major challenges need to be pull through such as the functionalizing of the thermoset compos- ite surface by co-curing an appropriate thermoplastic interlayer or realizing a fast and robust welding process that fulfils all quality and mechanical require- ments. In the present paper, we investigated the potential of Polyetherether- ketone (PEEK) and its amorphous (PEEK A) and semi-cristalline (PEEK SC) states as interlayer materials, co-cured onto the thermoset composite. A surface preparation by atmospheric plasma process demonstrated that both PEEK state materials can be used as interlayer with auspicious resulting ad- hesion properties. The influence of the plasma treatment on surface properties and morphology is also experimentally characterized. An infrared (IR) welding process, barely studied in the literature, is studied to assemble hybrid struc- tural composite. In order to avoid the expected thermal degradation of the thermoset matrix, a dissimilar infrared heating input power is proposed. More- over, to decrease the possible thermal degradation of the thermoset composites during the fusion bonding, a dissimilar infrared welding process have been ex- plored. Single lap shear test and failure mode analysis have been performed to highlight the promising performance of PEI as well as PEEK interlayer based hybrid joint.

Joining of dissimilar thermoplastics and their composites is a challenge for thermal welding techniques due to different melting points. Reactive welding with an auxiliary functional material can offer the clear opportunities to develop joining processes due to robustness to joining dissimilar thermoplastic polymers and their composites. The current study employed reactive compatibilization to offer the possibility of joining an acrylic-based glass fiber composite to polyamide (PA)-12 by applying a hot-tool welding technique. For this purpose, composite plates are fabricated by a typical vacuum infusion and thin layer thermoplastic films are formed by a thermostamping of PA12 granules. Subsequently, the reactive welding of the interposed PA12 sheet and Elium®-GMA-Glass composite is conducted by hot-plate welding. A glycidyl methacrylate (GMA) as a compatibilizing agent is copolymerized with methyl methacrylate Elium® resin. During the hot-tool welding process of dissimilar thermoplastic material, GMA can react with the polyamide end groups. The heat distribution at the Elium® GMA/PA-12 interface is responsible for obtaining a strong joint. This study focuses on the functionality of the compatibilizer on the welding of acrylic-based composites with polyamide (PA)-12 while varying the assembly temperature. The flatwise tensile test proved the effectiveness of GMA on the interface bounding. The excellent bounding incompatible polymers Elium® resin (PMMA) and PA12 was achieved at 200 °C.

Infrared welding technology is currently used in the automotive industry to assemble very complex composite shapes made of short glass fiber reinforced polymers. Such applications are targeted more towards short joining times than towards the optimization of adhesive properties. Through this work, the authors joined their efforts on the experimental investigation of driving mechanisms and their optimization, enabling the welding of high-performance materials typically selected for aeronautics applications. The thermal field through the thickness and on the surface was investigated. The best configuration of the LM-PAEK/C laminate presented a single lap shear (SLS) strength of 43.5 MPa with a standard deviation of 0.7 MPa compared to a strength of 24.9 MPa with a standard deviation of 2.3 MPa obtained with the welding configuration without insulation. These results highlight the major effect of a thermal gradient during infrared welding. It is specific to infrared welding to observe that the major resulting defects are located not at the interface area but inside the composite substrate, where voids, generated during the heating step, are unable to be reconsolidated during pressure application. The impact of the decompaction behavior on the thermal gradient was studied through a MATLAB© implemented 1D numerical model, developed internally and called “LysIR”.

The growing concern for climate change and global warming has given rise to investigations in various research fields, including one particular area dedicated to the creation of solid sorbents for efficient CO2 capture. In this work, a new family of poly(ionic liquid)s (PILs) comprising cationic polyureas (PURs) with tetrafluoroborate (BF4) anions has been synthesized. Condensation of various diisocyanates with novel ionic diamines and subsequent ion metathesis reaction resulted in high molar mass ionic PURs (Mw = 12 &divide, 173 &times, 103 g/mol) with high thermal stability (up to 260 &deg, C), glass transition temperatures in the range of 153&ndash, 286 &deg, C and remarkable CO2 capture (10.5&ndash, 24.8 mg/g at 0 &deg, C and 1 bar). The CO2 sorption was found to be dependent on the nature of the cation and structure of the diisocyanate. The highest sorption was demonstrated by tetrafluoroborate PUR based on 4,4&prime, methylene-bis(cyclohexyl isocyanate) diisocyanate and aromatic diamine bearing quinuclidinium cation (24.8 mg/g at 0 &deg, C and 1 bar). It is hoped that the present study will inspire novel design strategies for improving the sorption properties of PILs and the creation of novel effective CO2 sorbents.