The main objective of this integrated project is to develop a new composite plastic material using agricultural raw materials which can be cultivated in marginal lands or in lands set aside from food production. Another important objective is to use pulp and natural fibre, and other biodegradable material, as filler or reinforcement in plastic composites instead of calciocarbonate and glass fibre, so reducing the possibilities of enviromental pollution.
A new composite plastic material is under development using agricultural raw materials which can be cultivated in marginal lands or in land set aside from land production. The first large scale applications of production of biomass by short rotation intensive culture (SRIC) are in progress with ginestra and robinia. Due to their capacity to block landslides in steep, sloping soils, these species have been planted along road slopes.
The best technique for gathering and pretreating the biomass is under study. It has been found that the best preparation of biomass to be converted into fibre is to chip the raw material directly after harvesting. This can be done by hand or by machine and the final product is a homogenous matter that must be dried to avoid fermentation. The best system of drying biomass economically has been found to be by passive solar drier. The drying may be performed in about 30 days, with a weekly moving of the chips, to avoid the fermentation. After this pretreatment, the moisture is reduced to about 15% allowing storage and transportation of the biomass and it is ready to be treated for fibre extraction.
The defibration (mechanical pulping) process is under study and a reaction device is being designed to remove part of the plant cuticle. A similar device was designed with a special rotor to ensure a homogeneous mixing of the material and a high speed grinder was made. A washing machine was designed and built, to wash the fibres from the cuticle. 2 vats were also built to contain the fibrous suspensions and all these components were connected to carry out a work cycle.
The delignification process (semichemical pulping) is also under study and a sample of ginestra fibres was obtained for chemical treatment from broom. The yield from the process of delignification was 42% and the final yield of the product supplied was 40%.
The objectives will be achieved by adopting the following approach:
A study will be carried out on the production of biomass for experiments and to assess the feasibility of an annual production of 15 000 to 20 000 tonnes of biomass per year which would be required for an industrial scale operation.
Procedures and machines to pretreat the raw biomass will be developed. The aim is to reduce biomass size before storage or transportation by mechanically removing the liquid (especially for ginestra) followed by solar drying. At this stage the shorter fibres should be made. Specific machines for performing these tasks do not exist and have to be developed.
Methods will be established to defibrate the biomass and to refine the fibres for further processing either through the wet or the dry route, depending on the length of the fibres. The machinery which is to be used will derive mainly from the pulping and delignification stages of traditional pulp making but special items will have to be developed to handle these fibres and to refine them specifically to the level demanded by the further processing. The product obtained at this stage is essentially semichemical pulp which can be processed in conventional paper machines.
The most suitable fibres will be processed through the dry forming route. This involves web formation, binding with starch derived binders or dry binders, calendering, and embossing in a way which already imparts the preferential mechanical resistance demanded by components to be finally made. The basic dry forming process of Dan Web, specifically developed for shorter pulp fibres will be used. However, several process adjustments and redesigning of some of the equipment will be necessary.
The improved blending of fibres and plastic will be developed for car body production, the fibres coming from ginestra and black locust.
Funding SchemeCSC - Cost-sharing contracts
36030 San Vito Di Leguzzano Vicenza