Low-Density Cardoon (Cynara cardunculus L.) Particleboards Bound with Potato Starch-Based Adhesive.

In the present work, and for the first time, totally biosourced low-density particleboards were produced using cardoon particles (a no added value by-product from the Portuguese cheese making industry), bound with a potato starch adhesive. Different starch/cardoon ratios (0.6, 0.8, 1 and 1.2) were tested and the effect of different bio-based additives (chitosan, wood fiber and glycerol) on the performance of the adhesive system was evaluated. The best result was obtained for a formulation with a starch/cardoon mass ratio of 0.8, a chitosan/starch mass ratio of 0.05 and a water/starch mass ratio of 1.75. The particleboards produced had a density of 323 kg·m-3, internal bond strength of 0.35 N·mm-2 and thickness swelling of 15.2%. The values of density and internal bond strength meet the standard requirements of general-purpose lightweight boards for use in dry conditions according to CEN/TS 16368 specification. Moreover, the susceptibility of the formulations with best results was established against subterranean termites and one decay fungi.

Use of Multi-Hollow Polyester Particles as Opacifying Agent for Injection-Molded Polyethylene.

Titanium dioxide is considered the most efficient white pigment for opacification of thermoplastics. However, its high cost, combined with strong price oscillations due to production bottlenecks, has been driving the industry towards alternatives that might allow reducing the titanium dioxide content, while maintaining the product's opacity. A strategy commonly used in waterborne paints consists in adding hollow polymer particles to the formulation, therefore achieving opacification due to light refraction at the air/polymer interface. In the current work, we show preliminary results that indicate that a similar strategy can be followed for thermoplastics opacification, as long as thermoset particles are used, in order to ensure preservation of the hollow geometry during melt-processing. Multi-vesiculated crosslinked styrene-polyester particles, produced by a single-step double emulsion process, are used. Evidence of synergic interaction between the multi-hollow particles and titanium dioxide has been found.