Sunflower (Helianthus annuus) represents one of the most successful agricultural crops, typically grown for vegetable oil production, mostly used for food applications. In this review, the application of various products derived from parts of sunflower plants other than the seed cotyledon in the manufacturing of sustainable composites is considered. In particular, three concurring systems are here intersected with variable degrees of evidence. These are respectively built on seed residues as hardening fillers, on plant bast for lignocellulosic fibre/particles production, and on sunflower oil for bio-resin development. Data reported from literature indicate that seed husk does constitute a present and valuable resource, being necessarily separated during the oil production process. In contrast, the use of sunflower stems with their typical three-parted structure, including epidermis, fibrous secondary structure, and internal xylem, though offering a variety of behaviours, is still poorly exploited. As regards excess sunflower oil production, its use in the synthesis of alkyd or epoxy resins from triglycerides remains largely germinal, while the development of bio-polyurethanes using sunflower polyols has received limited attention so far. In spite of these caveats, the strength of the productive system based on sunflower cultivation and the abundance of raw matter suggest that in the future all these sectors will expand and be competitive with other sources for the production of biomass composites. In particular, this review, despite the literature gaps, tries to elucidate which issues hinder the eventual production of an all-sunflower composite (bio-matrix, cellulose fibres and ligneous fillers) in the near future, which could be an example of industrial product from a single cultivation chain.
Latini et al. (Fri,) studied this question.