materials feature | Bioplastics Aimplas is
compounding hemp-rein- forced PLA
biocomposites as part of the Naturtruck project
retardance as well as high-quality surfaces. “Those biocomposites will be a real alternative to
low-gloss standard ABS grades at a competitive cost,” says a representative at Aimplas, the Spanish technol- ogy institute which is one of the project members. Early work in the project has involved treatment of
natural fibres to improve their properties and compat- ibility with the PLA. This was carried out by IWNiRZ, a fibres institute in Poland. “The best results were achieved for degummed hemp fibres treated first with silanes and then with plasma,” says Miguel Angel Valera, a compounding researcher at Aimplas. Aimplas has also developed injection mouldable fire
retardant PLA/hemp fibre composites that achieved HB classification according to the UL94 standard. “The thermal stability of the composites was drastically improved by the use of natural antioxidants (polyphenol extracts),” Valera says. A third member of the project, CTAG (Automotive
Volvo is a
partner in the Naturtruck project looking at using biocomposites instead of ABS in truck interiors
Centre of Galicia in Spain), designed two prototype truck cab interior parts. The final design has already been validated through Moldflow simulation and injection moulding trials. CTAG used an infrared annealing process of the parts (applied on-line and post-injection) to improve the crystallinity and hence the heat deflec- tion temperature (HDT) of the biocomposites. The post-injection process raised the crystallinity of the biocomposites from 13% to 65%, Valera says. Aimplas has also studied annealing using microwave
irradiation. Valera says this raised the crystallinity of PLA/kenaf composites by 30% and increased the HDT under a load of 0.45 MPa from 56°C to 154°C. Natureplast in France has recently developed
compounds based on PLA for products manufactured using injection moulding. “PLA products don’t generally exhibit a high temperature resistance. Recent develop- ments in PLA chemical nature can overcome this
drawback, but these new grades are difficult to use in injection moulding, as the cooling time has to be high,” says Natureplast R&D manager Laurent Bélard. “We have worked to reduce significantly the cycle time, and the results have been particularly promising.” Bélard says Natureplast, through its R&D subsidiary
Biopolynov, now has PLA grades with improved mechanical and thermal properties compared to standard PLA, and improved productivity compared to existing heat-resistant PLA grades. He says pricing is “competitive.” The new grades, PLHT 201 and PLHT 202, “offer
comparable if not superior thermal and mechanical properties to equivalent existing materials,” he says. “Trials made also allowed gain in cycle times from 30% up to more than 200%, depending on injected parts.” Polyhydroxyalkanoates producer Metabolix is now
marketing its Mirel amorphous (a-PHA) copolymers as delivering key performance improvements to PLA compounds for a variety of packaging and consumer applications. Metabolix says that a-PHA can bring a number of desirable effects to PLA, such as increased toughness, even at low loading levels. Grades are currently being used in food contact and packaging applications. Metabolix showcased its products as performance
additives at NPE 2015 earlier this year, displaying customer samples from each of its target applications spaces. It says that interest in its biopolymers as performance additives for a range of materials as well as for bio-based content and biodegradation was high. Metabolix highlighted a-PHA as a performance modifier for PLA with a clear packaging film, for example. The amorphous copolymers “represent a significant
bioscience and engineering breakthrough because they deliver key performance improvements in PLA com- pounds, thereby extending the application range for PLA,” says a representative. “For example, a-PHA can
34 COMPOUNDING WORLD | June 2015
www.compoundingworld.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78