Biobased Composites by Photoinduced Polymerization of Cardanol Methacrylate with Microfibrillated Cellulose

Abstract

Biobased monomers and green processes are key to producing sustainable materials. Cardanol, an aromatic compound obtained from cashew nut shells, may be conveniently functionalized, e.g., with epoxy or (meth)acrylate groups, to replace petroleum-based monomers. Photoinduced polymerization is recognized as a sustainable process, less energy intensive than thermal curing; however, cardanol-based UV-cured polymers have relatively low thermomechanical properties, making them mostly suitable as reactive diluents or in non-structural applications such as coatings. It is therefore convenient to combine them with biobased reinforcements, such as microfibrillated cellulose (MFC), to obtain composites with good mechanical properties. In this work a cardanol-based methacrylate monomer was photopolymerized in the presence of MFC to yield self-standing, flexible, and relatively transparent films with high thermal stability. The polymerization process was completed within few minutes even in the presence of filler, and the cellulosic filler was not affected by the photopolymerization process.

Facile synthesis of cardanol‐based reactive diluents and application for anti‐shrinkage UV‐curable resins

“…8 Cardanol is the main component of renewable resources from cardanol shell liquid, and there are rigid benzene ring and flexible C15 unsaturated chain in its structure, 18,19 which was used to preparation of cardanol-based softener, surfactant, diluent. [20][21][22][23][24][25][26] Cardanol was utilized to fabricate UV-curable resins, which endow UV-curing resin with good flexibility, hydrophobicity, heat resistance, and other excellent properties. [27][28][29][30][31] Our group has prepared a series of biobased prepolymers and reactive diluents to obtain high bio-based content and low volume shrinkage of UV-curable resins, but the shrinkage mechanism has not been reported so far.…”

“…Cardanol is the main component of renewable resources from cardanol shell liquid, and there are rigid benzene ring and flexible C15 unsaturated chain in its structure, 18,19 which was used to preparation of cardanol‐based softener, surfactant, diluent 20–26 . Cardanol was utilized to fabricate UV‐curable resins, which endow UV‐curing resin with good flexibility, hydrophobicity, heat resistance, and other excellent properties 27–31 .…”

A hybrid methacrylate‐norbornene‐thiol photopolymerization system with tunable physical and mechanical properties

“…The kinetics of the photo‐homopolymerization of EGDEMA were analyzed by taking samples every 3 min during irradiation for a total of 18 min and monitoring the double bond peak in FTIR for conversion. The bands corresponding to the methacrylate double bond at 1638 cm −1 (CC stretching), 37 and at 814 cm −1 (CCH 2 twisting) 38 as secondary confirmation, as well as 3046 cm −1 (CCH stretching corresponding to the norbornenyl double bond) were monitored in the FTIR spectra during irradiation. The vibrations in the spectra changed upon irradiation, and those corresponding to the double bond clearly decreased as the reaction proceeded through the double bond; the kinetic graphs following the methacrylate conversion are shown in Figure S2.…”

Photocured Composite Films with Microfibrillated Cellulose: A Study of Water Vapor Permeability

“…Although the use of solvent in the impregnation step lessens one of the advantages of photopolymerization, i.e., being a solventless process, this allowed the preparation of composites containing high weight fractions of MFC, avoiding aggregation of the filler. In this way, acrylate and methacrylate monomers were photopolymerized inside an ethanol-swollen bacterial cellulose nanofiber network, obtaining collagen-like materials [16], and photocured cardanol methacrylatebased composites containing up to 45 wt.% of MFC were obtained by impregnation of preforms where water was exchanged with acetone [17]. Alternatively, dried preforms were impregnated with photocurable resins under reduced pressures (0.01-0.02 MPa) for 24 h, obtaining cellulose contents of up to 70 wt.% [18,19].…”