The Effects of High Temperature Treatment on the Physical Properties and Fire-retardant Performance of Fire-retardant Plywood

• Main Authors: Rao, Yu-chen, 饒玉珍
• Other Authors: Dr.Song-Yung Wang
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/12230351962338224779

碩士 === 國立臺灣大學 === 森林學系 === 85 === Summary This research evaluates the effect of fire-retardant treatment time on the physical and mechanical properties and combustibility of plywood by comparing the properties of a customized 3-layer plywood, which was glued from single plates by high-temperature-harden PF, untreated with any fire-retardant chemical with the properties of one with spraying treatment then pressed to 5.5mm thick, and the properties of one with dipping treatment of two fire-retardant chemicals（AF21 and立安302）then pressed to 10.5mm ick. All plywood were high temperature treated for 80 days(77℃, 50%RH). In our work, we also study the accommodation effect on temperature and humidity of the fire- retardant plywood we developed while they were used as in-door decoration materials. The effect of fire-retardant chemicals on the combustibility using heat analysis technique is studied as well. The result shows that the physical and mechanical properties of the fire-retardant treated plywood present declined trends. MOE values, MOR values, and shearing strength of glue-coupling of flame-retardant and fire-retardant plywood are lower than those of untreated plywood vary with composition of chemicals. Both properties are proportional to the amount of chemicals absorbed. In addition, as strength of static bending is concerned, after 80 days of high temperature heating treatment tests, MOE and MOR values of all kinds of plywood are inverse proportional to the heating time, 6.5%∼47.3%. The heating treatment affects chemical treated plywood more than the one without chemical treatment. Especially, the plywood treated with 立安302 shows a clear declining tendency. In the aspect of shearing strength of glue-coupling, after 80 days of high temperature heating treatment testing, l plywood, no matter treated with chemical or not, shows declined tendencies (15.0%∼42.3%) on glue-coupling shearing strength of normal type and boiling-water-durable type as high heating time grows. Also, heating treatment affects fire-retardant treated plywood more. With the same heating time, it shows following glue-coupling shearing strength tendencies： UST > AST > LST, USTW > ASTW > LSTW, UDT > ADT > LDT, and DTW > ADTW > LDTW. When the fire-retardant chemicals are concerned, no matter what kind of gl is used, 立安302 treated plywood seems will be affected more. All wooden material can became in-door decoration material with excellent capability of accommodation humility, however, their properties vary with fire retardant. The hygroscopic- conditioning index (b values) of flame-retardant plywood and fire-retardant plywood, both treated with AF21, are 0.0224 and 0.0250, all belong to Type 1, respectively. These two values are greater than 0.0181 and 0.0183（belong to Type 2）, the value of their counterparts of plywood which haven't treated with chemical and have samthickness. The values also greater than 0.0195 and 0.0197(belong to Type 2 ), the values of their counterparts of plywood after 80 days heating treatment. The result shows that the chemical treatment can play a important role on accommodating humidity of wooden materials. When concerning burning properties, after 80 days of high temperature treatment, the burning properties of plywood treatment with AF 21 or 立安302 all are affected. Especially , the one treated with 立安302 shows a more notable effect. Within it, AST and ADT pass flame-retardant tests specified in CNS 8736 standard and 3rd level fire-retardant tests specified in CNS 8737. However, the LST after 20 days and 30 days heating treatment didn't pass the flame-retardant tests specified in CNS 8736. This may be dueo influence of composition of chemicals and equilibrium moisture content（EMC）. In addition, using TGA and DSC testing curves of heat analysis knowing the heat decomposition activities under high temperature environment, we find that fire-retardant chemical performs its effect making pyrolysis temperature declined and accelerating the generation of carbon residues.