Fungus and fire resistance of insulation mats based on water glass bonded non-textile flax fibres
Materials and methods Field retted flax crop were processed to fine non-textile fibres as specified elsewhere (Grohe 2003) and the material employed for the manufacturing of insulation mats. Water glass was applied as an adhesive and a solution prepared by adding 50 vol.% water to the received viscous water glass (Betol 39T1, 36 wt.% solids in water, Woellner Silikat GmbH, Ludwigshafen, Germany;) leading to 18 wt.% solids in water (pH 11). An aqueous borate solution of 14 wt.% boric acid and 10 wt.% sodium hydroxide (33 wt.% NaOH solution) was mixed, giving 24 wt.% solids in water (ph 13). Thus, the mixture contains a fraction of 21.6 wt.% of the flame retardant and fungicide Borax (Na2B4O7·10 H2O). The B(OH)3-solids and the NaOH-solution were received as technical grade by Zschimmer und Schwarz, Lahnstein, Germany. Insulation mats were fabricated via a pilot plant, as described by Grohe 2003. During the process flax fleeces were sprayed either with (A) water glass or with (B) water glass and subsequently with the boric compound. Some insulation mats were fabricated by primarily spraying them with (C) boron-solution followed by another cycle comprised the spraying of water glass and boric compound. Test-series were carried out (Bundesanstalt für Materialforschung und -prüfung, Berlin, Germany) to investigate the biological resistance of insulation mats fabricated via the production runs (A), (B) and (C) (see Table 1). Thereby, five samples (90 · 90 · 40–55 mm) of each production run were exposed to pure cultures of the wood destroying fungal species Aspergillus niger, Aspergillus terreus, Aureobasidium pullulans, Paecilornyces variotii, Penicillium funiculosum, Penicillium ochro-chloron, Scopulariopsis brevicaulis and Trichoderma viride and the degree of fungal attack verified, according to DIN IEC 68-2-10. To investigate the fire properties of insulation mats five samples of the series (B) were tested according to DIN 4102-1 (FIW—München, München, Germany).
Evaluation and fireproofing treatment of wooden heat-insulating/acoustic absorbing materials
Heat insulating and acoustic absorbing materials were endued with fireproof performance and subjected to quantitative evaluations assuming a variety of uses and situations. Fireproofing was performed by spraying an aqueous solution of flame retardants on raw materials (wood shavings, kenaf bast fibers, and core-sheath-type fibers) during the fiber spreading and mixing step. It was possible to treat the materials homogeneously and without increasing manufacturing workload. Flame retardancy was evaluated using vertical flame testing, horizontal flame testing, the 45° Meckel’s Burner method, and a cone calorimetry method in accordance with UL94, JIS D 1201, JIS L 1091, and JIS A 9521, respectively. It was possible to achieve results that satisfied each of these standards, along with quantifying the relations between treatment conditions and performance.
Capillarity of flax/linseed (Linum usitatissimum L.) and fibre hemp (Cannabis sativa L.) straw fractions
Abstract In a study of the wetting properties of the fractions of unretted and frost-retted fibre straws a method to separate fibre, fine shive, and coarse shive from fibre plants is introduced and tested on bast fibre plants ( Linum usitatissimum L. and Cannabis sativa L.) The method consists of optional drying of stalks, cutting of straws, milling the straws with a hammer mill, separating fibres from shives with a drum separator, separating coarse shives from fine shives with a screen and a stream of air and finally cleaning of the fine shive with sieve vibrator. The described method works best for frost-retted plants and for unretted, green flax. The capillarity properties of these fractions were studied by measuring the amount of absorbed water as a function of time. The required time for the best-absorbing fibres of unretted and frost-retted hemp and unretted flax to absorb their own masses of water is less than 10 min compared with 2 h for the poorest-absorbing frost-retted flax. Overretting by frost retting seems to have an opposite effect on flax/linseed and hemp fibre capillarity. Both unretted and frost-retted coarse shive fractions behave quite similarly. If good absorption is needed, (over)retted hemp fibre should be used. If poor fibre absorption is desirable, (over)retted flax/linseed seems to have this feature.