You are here

New applications: PLA-wood fibre composites

News International-French

5 Apr 2011

Bioplastics are developing significantly today. Natural wood (Lignocel) and cellulose (Arbocel) fibres are used for mechanical reinforcement, economic improvement, better processability, and as a solution to raw-material shortage and shelf-life variation.

(Published on December 2007 – JEC Magazine #37)




Following the presentation “New applications in the woodplastics composites sector: the French example” by the author at the Biocomposites Forum of the JEC Composites Show 2007, new developments, applications and products are now available. Apollor and Rettenmaier have been partnering to develop starch-wood fibre composites (Figure 1). Rettenmaier is also working with FuturaMat to propose a PLA-wood fibre compound, and carrying out joint research with the Ecole des Mines de Douai on injection moulding of PLA-cellulose fibre composites.



Starch-wood fibre composites

Apollor is a technological resource centre that specializes in polymer and composite materials. The centre carries on research to industrialize new material, product or process concepts, and one of its objectives is to foster the creation of new activities and support companies in their innovation approach. To this end, Apollor develops new materials, such as composites using natural fibres or biodegradable polymers. The centre can test and research customised formulations meeting the needs of a specific company. In co-operation with Rettenmaier, the centre developed several combinations of starch and wood fibres, preparing three different grades:

  • 80% starch and 20% wood fibres,
  • 70% starch and 30% wood fibres,
  • 60% starch and 40% wood fibres.


More Information.....
The JRS Company (J. Rettenmaier & Söhne) is a producer of wood, cellulose and food fibres. For many years, it has developed applications for global industries as varied as pharmacy, industrial filtration, food, vegetable litters, road construction, chemical construction and, of course, plastics. JRS offers industrialists a broad range of wood (Lignocel®) and cellulose fibres (Arbocel®) (Figure1), distinguishing itself by the high and consistent quality of its products, their reproducibility and their diversity adapted to varied applications. These fibres result from either softwood (conifers) or hardwood (leafy trees). The range offers various particle sizes and water contents (lower than 2% for certain products).


With a wood-fibre reinforcement, the Young’s modulus of the mix containing 40% wood fibres is multiplied by 6.5 (Figure 2).



These compounds (starch + wood fibres) remain 100% compostable and are derived from natural resources. Multiple applications are possible: replacing existing products, developing new “green” product lines, or expanding existing product lines.


Natural cellulose and wood fibres are currently used to reinforce engineered bioplastics (starch, PLA), optimize costs, decrease or increase the biodeterioration of composites and, finally, mitigate the availability shortage of certain bioplastics.


Plant-based polyester-wood fibre compound

Using agricultural and forest resources to create bioproducts offers significant environmental advantages. Contrary to their fossil counterparts, renewable materials and energies derived from biomass make it possible to reduce energy consumption and gas (CO2) emissions, or to decrease the impacts on air, water or ground. FuturaMat produces and sells sophisticated thermoplastic products based on wood flours whose formulations were patented by the researchers of the Valagro R&D platform. These compounds (pellets) are used as new raw materials by plastic processors in injection moulding, extrusion, and calendering.


The BioFibra® range, based on vegetable and compostable raw materials, is currently under development. Two grades are already available: PL30E11 and PL30E26. Entirely produced from renewable carbon (plant-based polyesters, wood and plant additives), BioFibra® products are compostable in a few weeks. The bio-assimilation results in water, CO2 (aerobic) or CH4 (anaerobic), heat and reorganized biomass.


These materials are perfectly suitable for injection moulding processes (Figure 3).



They are used in applications such as horticulture, packaging and, more generally, single-use technical parts. The formulations can be customised according to the customer’s requests, thanks to FuturaMat’s expertise in the bioplastics field and Rettenmaier’s expertise in the woodfibre field.


PLA-cellulose fibre composites

The Polymers and Composites Technology & Mechanical Engineering Department (TPCIM) of the Ecole des Mines de Douai worked with manufacturers to launch a project which aims at producing injection-moulded parts made of a PLA matrix with cellulose fibres (Figure 4).



The cellulose fibres, provided by JRS, have the advantage of being easier to use than hemp or flax in the extrusion phases (mixture) and then in injection.


The structure of these wood-derived white cellulose fibres is more flexible and elastic than that of wood fibres. The elimination of lignin after wood extraction improves compatibility with PLA and avoids premature UV ageing. Various mixtures using different cellulose grades and contents were formulated to study the effect of the length and amount of fibres in the composite (Figure 5).



The following effects were highlighted:


  • cellulose fibres clearly improve the modulus compared to virgin PLA, especially in traction at 80°C;
  • reduced material cost;
  • variable shelf-life;
  • short fibres are homogenized more easily in the matrix.