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本文利用落叶松刨花和自制的异氰酸酯胶粘剂 ,通过正交重复实验研究了刨花板制造工艺参数中的密度、热压温度、热压时间、刨花含水率、施胶量和施蜡量对“2 4h吸水厚度膨胀率”与“不可逆厚度膨胀率”差的影响 ,同时通过单因素重复实验对刨花板制造常用的胶种和刨花种类对厚度膨胀率差也进行了研究。结果表明 ,在上述热压参数中 ,只有板的密度和刨花种类是影响刨花板“厚度膨胀率平行性”规律的显著性因素 ;结合和分析部分学者的实验结果发现 ,刨花形态和刨花预处理也是影响刨花板“厚度膨胀率平行性”规律的显著因素。研究表明前者对刨花板“厚度膨胀率平行性”规律影响的实质是不同密度刨花板在 2 4h的吸湿膨胀的速率与程度差异所致 ,后者则是由于这些因素影响了木材的吸湿膨胀特性所致 相似文献
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利用杨树人工林剩余物生产刨花板可行性研究 总被引:1,自引:0,他引:1
The composite board industry in Iran is obliged to use residues from forest operation as well as wood industry for competing
with paper industry because of shortage of wood. In the present study we investigated the residues from poplar plantation
used for particleboard production. Three kinds of wood materials, poplar branches, small diameter poplar wood (3–8 cm) and
beech wood, were used in the experiment of particleboard production. The results demonstrated that the characteristic of particleboard
made from poplar branches and small diameter wood is comparable to that made from mature beech wood. To avoid too much residual
acid in the final board, the properties of boards produced with 1.5% hardener at 175°C press temperature are acceptable, although
the properties of particleboard produced with 2% hardener were higher than were higher than that of the board produced with
lower hardener (1% or 1.5%).. The MOR, MOE and IB of particleboard made from branches were measured as 14.57, 2015, and 1.32
MPa, respectively, while The MOR, MOE and IB of particleboard produced from small diameter poplar wood were 19.90, 2199, and
1.86 MPa, respectively. The thickness swelling of boards made from branches after 2 and 24 h immersion in water was 20.14%
and 31.26%. The utilization of branches and very small diameter wood of poplar is recommended for the survival and developments
of particleboard industry in Iran. 相似文献
3.
采用脲醛树脂(UF)/聚合异氰酸酯(PDMI)组合胶黏剂,以不同的组合配比在较低热压温度(160℃)条件下用高含水率(9.0%)杂木刨花制备刨花板,检测其静曲强度、内结合强度以及2h和24h吸水厚度膨胀率。结果表明:聚合异氰酸酯(PDMI)的引入,可以显著提高刨花板的物理力学性能和耐水性能;将刨花终含水率提高至9.0%可节约刨花干燥能耗达13.0%以上;与脲醛树脂胶黏剂(UF)相比,使用PDMI/UF配比为1∶9的(10.0wt%PDMI)组合胶黏剂可以提高刨花板静曲强度80%,提高内结合强度150%;在不添加防水剂的条件下,可以将板材的2h吸水厚度膨胀率由31.0%提高至21.0%。该研究可为刨花板节能环保生产提供新思路。 相似文献
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烟秆制备刨花板的力学性能研究 总被引:1,自引:0,他引:1
烟秆为烟草采摘烟口t-后的废弃物,为了更好的利用这种原料,利用不同含水率(9%、6%、3%、0%)和烟秆不同部位(上部、中部和下部)的刨花制成刨花板,测定刨花板的内结合强度、弹性模量和静曲强度,分析含水率和烟秆部位对刨花板力学性能的影响。结果表明,随着含水率从0增加至9%,刨花板的内结合强度从0.35MPa增加至0.58MPa,其弹性模量和静曲强度呈先增后减趋势,当含水率在6%时,烟秆刨花板的弹性模量和静曲强度最大。不同部位的烟秆刨花对刨花板的内结合强度、弹性模量、静曲强度有显著影响,其中,利用中部烟秆刨花制备的刨花板的内结合强度、弹性模量、静曲强度最小。利用烟秆刨花制备的刨花板其力学性能能达到国家标准的要求,因此利用烟秆制备刨花板是可行的。 相似文献
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复合工艺对竹/塑复合刨花板性能的影响 总被引:1,自引:0,他引:1
利用聚乙烯(PE)粉末取代部分脲醛树脂(UF)胶黏剂,与竹刨花制备三层结构竹/塑复合刨花板。通过正交试验探讨PE添加量、UF施胶量、热压温度及热压时间对竹/塑复合刨花板主要物理力学性能的影响。结果表明:较优工艺组合为PE添加量6%、UF施胶量2%、热压温度205℃、热压时间12s/mm,竹/塑复合刨花板达到LY/T1842—2009《竹材刨花板》A类理化性能指标要求;2h吸水厚度膨胀率和甲醛释放量分别为2.6%和2.4mg/100g,与普通竹材刨花板对比,分别减少了54.4%和54.7%;静曲强度达到19.6MPa,提高了14.0%。采用PE粉末替代部分UF胶黏剂生产竹/塑复合刨花板可行,且具有广泛的应用前景。 相似文献
6.
We investigated the bending properties of composite boards produced by reinforcing both sides of corrugated particleboard with medium-density fiberboard (MDF). Thickness swelling and linear expansion (LE) were measured to assess the dimensional stabilities of the composite board. Although the apparent density of the composite board was 0.48g/cm3, its strength was found to be equivalent to that of 18-type particleboard as described in JIS A 5908. The boards parallel/perpendicular anisotropy in strength was 0.9. The modulus of rupture (MOR) of the composite board increased with board density only up to a certain density, beyond which the MOR was constant. On the other hand, the thickness swelling of both corrugated particleboard and the composite board was smaller than that of flat-type particleboard, satisfying the JIS A 5908 standard of 12%. Linear expansion (soaking in water of ordinary temperature for 24h) of corrugated particleboard was 0.7%–0.9% in the parallel direction and 2.1%–3.1% in the perpendicular direction; hence, anisotropy in linear expansion existed in the corrugated particleboard. The linear expansion of the composite board was 0.6%–0.9% in the parallel direction and 1.8%–2.5% in the perpendicular direction. Although the LE of the composite board was lower than that of corrugated particleboard, it is necessary to improve the LE of composite board for practical use. 相似文献
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在实验室制备得到树脂型甲醛捕捉剂,考察了甲醛捕捉剂与不同F/U摩尔比脲醛树脂混合使用后制备得到的刨花板力学性能及甲醛释放量。研究结果表明,甲醛捕捉剂的添加能有效降低刨花板的甲醛释放量,但对混合树脂的最终力学强度性能不利。混合树脂的摩尔比F/U是决定相关刨花板力学性能及甲醛释放量的主要因素。当与摩尔比F/U=1的脲醛树脂混合使用时,添加占总施胶量5%甲醛捕捉剂的刨花板甲醛释放量可达到E1级,同时,内结合强度值满足室内级国家标准要求。与摩尔比F/U=1.2的脲醛树脂混合使用,当甲醛捕捉剂的添加量为20%时,刨花板性能达标。 相似文献
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以废旧建筑模板和家具为原料,使用环保型无机胶黏剂制备刨花板。利用扫描电子显微镜(SEM)观察刨花板的微观形貌,同时利用量热仪、氧指数测定仪、同步热分析仪等评价板材的阻燃性及热稳定性。结果表明:当板材密度为0.95g/cm^3时,除24h吸水厚度膨胀率外,其余物理力学性能均符合国标中的P3型刨花板要求;SEM观察到无机胶黏剂包覆刨花,填充板材孔隙,使板材物理力学强度大幅提高;选择氯化镁为固化剂,当表层/芯层刨花的固化剂用量为4.5%/5.0%时,压制的密度为0.95g/cm^3的刨花板,其氧指数为31%,具有较好阻燃性能。 相似文献
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大豆蛋白胶稻草碎料板制备关键工艺参数研究 总被引:1,自引:0,他引:1
采用自制大豆蛋白胶,通过热压法对稻草碎料板的制备工艺参数进行了系列试验的结果表明:稻草碎料板的静曲强度(MOR)在施胶量为71%时(相当于粗蛋白添加量为12%)最强,接近GB/T 21723-2008的要求;稻草碎料板的内结合强度(IB)随着施胶量的增大而增强,在施胶量为82%时(相当于粗蛋白添加量为18%),内结合强度接近GB/T 21723-2008的要求;稻草碎料粒径对稻草板的静曲强度和内结合强度影响不显著,稻草碎料板的静曲强度和内结合强度随板材表观密度增大而显著增强。 相似文献
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A landscape model (LANDIS) was used to study the long-term forest dynamics under five planting types (100% larch (P1); 70% larch and 30% Mongolian Scotch pine (Pinus sylvestris var. mongolica) (P2); 50% larch and 50% Mongolian Scotch pine (P3); 30% larch and 70% Mongolian Scotch pine (P4); 100% Mongolian Scotch pine (P5)), which were also employed in severely burned area under current planting intensity, and under natural regeneration (as
a comparison) in Tuqiang Forest Bureau in the northern slopes of Great Xing’an Mountains after the catastrophic fire in 1987.
Results showed that different planting types had a significant influence on the abundance of larch, Mongolian Scotch pine
and white birch. The abundance of larch increased with time, whereas the abundance of Mongolian Scotch pine was in a converse
way. The abundance of larch and Mongolian Scotch pine under these planting scenarios was higher than that under natural regeneration.
Under these planting scenarios, the abundance of larch increased with the increasing proportion of larch, and the abundance
of Mongolian Scotch pine was in a similar way. Contrary to larch and Mongolian Scotch pine, white birch had higher abundance
under natural regeneration than that under these planting scenarios. Also, the different proportions of larch and Mongolian
Scotch pine had an influence on the abundance of white birch. White birch had higher abundance with the increasing proportion
of Mongolian Scotch pine. As for the total abundance of larch and Mongolian Scotch pine, the difference was not significant
under P2, P3 and P4 scenarios, but was higher than that under P1 and P5 scenarios, which indicated that individual-species planting should not
be used in the forest landscape.
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Translated from Chinese Journal of Applied Ecology, 2006, 17(5): 855–861 [译自: 应用生态学报] 相似文献
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对13个家系数据进行分析的结果表明,各家系间差异极显著,杂种落叶松相对于单亲本落叶松优势非常明显。杂种落叶松不同品种在不同地点的高生长量都远超单亲本落叶松,且不同品种在不同地点具有一定的稳定性,日×兴、兴×日的正反交品种在黑龙江省各地表现良好,具有一定的推广价值。 相似文献
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The flow of labeled carbon in ectomycorrhizal and non-ectomycorrhizal seedlings of Japanese larch (Larix kaempferi Sarg.) and its F1 hybrid (Larix gmelinii Rupr. x L. kaempferi) was studied. Larch seedlings were grown in a greenhouse for 110 days with larch forest soil (FM) or Suillus grevillei (SM) inoculum, or in the absence of ectomycorrhizal fungi (NM). Shoots of colonized and NM seedlings were exposed to a pulse of 14CO2 for 1 h under natural light. Seedlings were harvested following 0, 6 and 24 h of exposure to 14CO2. At the final harvest, SM seedlings of Japanese larch and hybrid larch allocated 2.6 and 2.5% more 14C, respectively, to roots than NM seedlings. In contrast, FM seedlings of Japanese larch and hybrid larch allocated 6.5 and 18.0% more 14C, respectively, to the stem than NM seedlings. Of the total 14C detected in needle, stem and root fractions, FM and SM seedlings allocated a greater proportion than NM seedlings, perhaps because FM and SM seedlings had significantly (P < 0.05) higher photosynthetic rates than NM seedlings. As a result, FM and SM seedlings had greater dry masses than NM seedlings. Concentrations of nitrogen and phosphorus in FM and SM seedlings were significantly (P < 0.05) higher than in NM seedlings, as was stomatal conductance. 相似文献
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The intercropping system of tree with soybean in juvenile plantations, as a short-term practice, was applied at Lao Shan Experimental
Station in Mao’er Shan Forest of Northeast Forestry University, Harbin, China. The larch (Larix gmelinii)/soybean (Glycine max.) and ash (Fraxinus mandshurica) intercropping systems were studied in the field to assess the effects of the intercropping on soil physicochemical properties.
The results showed that soil physical properties were improved after soybean intercropping with larch and ash in one growing
season. The soil bulk density in larch/soybean and ash/soybean systems was 1.112 g·cm−3 and 1.058 g·cm−3, respectively, which was lower than that in the pure larch or ash plantation without intercropping. The total soil porosity
also increased after intercropping. The organic matter amount in larch/soybean system was 1.77 times higher than that in the
pure larch plantation, and it was 1.09 times higher in ash/soybean system than that in the pure ash plantation. Contents of
total nitrogen and hydrolyzable nitrogen in larch/soybean system were 4.2% and 53.0% higher than those in the pure larch stand.
Total nitrogen and hydrolyzable nitrogen contents in ash/soybean system were 75.5% and 3.3% higher than those in the pure
ash plantation. Total phosphorus content decreased after intercropping, while change of available phosphorus showed an increasing
trend. Total potassium and available potassium contents in the larch/soybean system were 0.6% and 17.5% higher than those
in the pure larch stand. Total potassium and available potassium contents in the ash/soybean system were 56.4% and 21.8% higher
than those in the pure ash plantation.
Biography: FAN A-nan (1972–), female, Ph. Doctor in Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P. R.
China. 相似文献
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