共查询到20条相似文献,搜索用时 812 毫秒
1.
管义榕 《林业机械与木工设备》2013,(9)
探讨了不同剖面密度分布的地板基材对模压地板主要物理力学性能的影响,揭示其变化规律。剖面密度分布不同的地板基材对模压地板成品的密度影响不大;剖面密度分布不同的地板基材,尤其是表层厚度对模压地板成品内结合强度、静曲强度、吸水厚度膨胀率的影响显著,表层厚度在2.0~2.4mm之间的地板基材压贴后的成品,其内结合强度下降的小,静曲强度下降大,吸水厚度膨胀率增加的多;表层厚度在1.2~1.5mm之间的地板基材压贴后的成品,其内结合强度下降大,静曲强度下降小,吸水厚度膨胀率增加少。 相似文献
2.
3.
4.
以酚醛树脂为胶粘剂,以竹束和木单板为原料,制造出室外用重组竹和重组竹木复合材,探讨了热压温度和压力对板材的弹性模量、静曲强度以及吸水厚度膨胀率的影响规律。结果表明:随着热压温度的提高,重组竹和重组竹木复合材的静曲强度、弹性模量、尺寸稳定性显著增加;在本研究范围内,热压压力对板材力的学强度和吸水厚度膨胀率的影响不显著;重组竹的静曲强度和弹性模量均明显高于重组竹木复合材,但其尺寸稳定性无显著区别;重组竹和重组竹木复合材的优化热压温度与压力分别为170℃和4MPa。 相似文献
5.
竹木复合中密度纤维板工艺条件的研究 总被引:11,自引:2,他引:9
研究了竹木纤维混合比、空比和纤维筛分值工艺条件对木复合中密度性能的影响。结果表明,在合适的工艺条件下,可以生产出具有优良性能的竹木复合中密度纤维板。竹木复合中密度纤维板的静曲强度、弹性模量和吸水厚度膨胀率随竹木纤维混合比的增大而增大;而平面抗拉强度在0/1~1/1范围内随竹木纤维混合比加大模量和吸水厚度膨胀率随竹木纤维混合比为1/1时,IB最小。板的静曲强度、弹性模量、平面抗拉强度和吸水厚度膨胀率 相似文献
6.
7.
竹材水泥碎料板制造初探 总被引:2,自引:0,他引:2
用正交试验法探讨竹材碎料的预处理方法,板材密度和水泥/竹材比对产品的静曲强度,吸水率和吸水厚度膨胀率的影响规律。研究结果表明,以竹材为原料制造水泥碎料板的竹材必须进行预处理,否则不能硬化成板;竹材水泥碎料板的静曲强度随着板的密度增大而增大,吸水率随板的密度增大而降低。水泥/竹材比对吸水率无显著影响;竹材水泥碎料板的吸水厚度膨胀率是随水泥/竹材比增大而降低,与板的密度无明显关系。 相似文献
8.
9.
本文研究了配料比对木纤维/聚丙烯复合材料物理力学性能的影响,研究结果表明:随着聚丙烯用量的增加,木纤维/聚丙烯复合材料的弹性模量、静曲强度呈先上升后下降趋势。当聚丙烯用量为25%左右时,弹性模量和静曲强度均达到较大值;随着聚丙烯用量的增加,吸水厚度膨胀率呈下降趋势,而密度略呈上升趋势。 相似文献
10.
11.
This paper describes the features of binderless particleboard manufactured from sugarcane bagasse, under a high pressing temperature of 200–280 °C. Mechanical properties [i.e., modulus of rupture (MOR) and elasticity (MOE) in dry and wet conditions, internal bonding strength (IB)] and dimensional stability [i.e., thickness swelling (TS)] of the board were evaluated to investigate the effect of high pressing temperature. Recycled chip binderless particleboards were manufactured under the same conditions for comparison, and particleboards bonded with polymeric methylene diphenyl diisocyanate (PMDI) resin were manufactured as reference material. The target density was 0.8 g/cm3 for all of the boards. The results showed that the mechanical properties and dimensional stability of both types of binderless boards were improved by increasing the pressing temperature. Bagasse showed better performance than that of recycled chip as a raw material in all evaluations. Bagasse binderless particleboard manufactured at 260 °C had an MOE value of 3.5 GPa, which was equivalent to the PMDI particleboard, and a lower TS value of 3.7 % than that of PMDI particleboard. The MOR retention ratio under the dry and wet conditions was 87.0 %, while the ratio for the PMDI particleboard was only 54.6 %. The obtained results showed the possibility of manufacturing high-durability binderless particleboard, with good dimensional stability and water resistance, which previously were points of weakness for binderless boards. Manufacturing binderless boards under high temperature was effective even when using particles with poor contact area, and it was possible to express acceptable properties to allow the manufacture of particleboards. Further chemical analysis indicated a contribution of a saccharide in the bagasse to the improvement of the board properties. 相似文献
12.
Miloš Ivković Washington J. Gapare Aljoy Abarquez Jugo Ilic Michael B. Powell Harry X. Wu 《Wood Science and Technology》2009,43(3-4):237-257
Development of optimal ways to predict juvenile wood stiffness, strength, and stability using wood properties that can be measured with relative ease and low cost is a priority for tree breeding and silviculture. Wood static modulus of elasticity (MOE), modulus of rupture (MOR), radial, tangential, and longitudinal shrinkage (RS, TS, LS), wood density (DEN), sound wave velocity (SWV), spiral grain (SLG), and microfibril angle (MFA) were measured on juvenile wood samples from lower stem sections in two radiata pine test plantations. Variation between inner (rings 1–2 from pith) and outer (rings 3–6 from pith) rings was generally larger than that among trees. MOE and MOR were lower (50%) in inner-rings than in outer-rings. RS and TS were higher (30–50%) for outer-rings than inner-rings, but LS decreased rapidly (>200%) from inner-rings to outer-rings. DEN had a higher correlation with MOR than with MOE, while MFA had a higher correlation with dry wood MOE than with MOR. SLG had higher significant correlation with MOE than with MOR. DEN and MOE had a weak, significant linear relationship with RS and TS, while MOE had a strong negative non-linear relationship with LS. Multiple regressions had a good potential as a method for predicting billet stiffness (R 2 > 0.42), but had only a weak potential to predict wood strength and shrinkage (R 2 < 0.22). For wood stiffness acoustic velocity measurements seemed to be the most practical, and for wood strength and stability acoustic velocity plus core density seemed to be the most practical measurements for predicting lower stem average in young trees. 相似文献
13.
半干法石膏纤维板工艺研究:Ⅰ.原料配比,密度等对板材性能的影响 总被引:2,自引:0,他引:2
本研究是建立在我国资源和工业技术基础之上,探讨利用木纤维以半干法制造石膏纤维板(GFB)的生产工艺;提出了半干法石膏纤维板的工艺方案,并建立了密度、木膏比、水膏比与板材性能的数学模型。结果表明:密度(D)增加,板材力学性能显著提高,木膏比(W/G)、水膏比(H/G)有效强的交互影响。木膏比增大,板材反弹率和吸水厚度膨胀率(TS)增加,纤维形态,蒸煮工艺对板材静曲性能无显著影响,纤维形态对内结合强度 相似文献
14.
Ajaye Babatunde 《林业研究》2011,21(1):111-115
Cement-bonded particleboards of 6 mm in thickness were manufactured using maize stalk (Zea mays) particles of uniform sizes at three levels of board density and additive concentrations respectively. The bending strength and dimensional properties were assessed. Increase in board density and additive concentration caused increase in Modulus of rupture (MOR), Modulus of elasticity (MOE), and decrease in Thickness swelling (TS) and Water absorption (WA). The MOR, MOE and TS of the boards were significantly affected by board density except for WA, but additive concentration affected all the boards’ properties examined at p ≥ 0.05. Strong and dimensional stable cement-bonded boards could be manufactured from maize stalk particles with Portland cement as the binder after hot water treatment. Although the dimensional stability and mechanical strength properties of the boards were affected by the board density and additive concentration, the study revealed that cement-bonded particleboards could be manufactured from maize stalk (Zea mays) particles. However, the increase in board density and additive concentration could cause the increase in MOR and MOE, and cause the decrease in TS and WA of boards. 相似文献
15.
16.
Gypsum particleboard (GPB) has high thickness swelling (TS), high water absorption (WA), and low mechanical properties compared with cement-bonded particleboard. The properties of GPB were improved by adding cement. The experimental results showed that GPB with the added cement had good physical and mechanical properties compared with those of gypsum particleboard with no added cement. The TS and WA of gypsum particleboard with added cement were reduced by 10%. The mechanical properties of GPB, such as internal bond strength (IB), modulus of rupture (MOR), and modulus of elasticity (MOE), increased when the GPB was made with added cement. The properties of GPB improved relative to the quantity of cement added. With an increase of cement content from 5% to 10%, the TS and WA were reduced, and the IB, MOR, and MOE were increased. In contrast, the TS and WA increased and the IB, MOE, and MOR decreased when the cement content was increased from 15% to 30%. Thus the physical and mechanical properties of GPB were successfully improved when the added cement content was 10%.An outline of this paper was presented at the 47th Annual Meeting of the Japan Wood Research Society in Kochi, April 1997 相似文献
17.
Summary Two types of particleboards bonded with an isocyanate resin, one with uniform vertical density profile (homo-profile), and
the other with conventional U-shaped profile, were fabricated to various density levels using lauan (Shorea spp.) particles. The fundamental relationships between the density profile and the board properties were determined, and
the results are summarized as follows:
1. In homo-profile boards, the moduli of rupture (MOR) and elasticity (MOE), internal bond (IB) strength, and screw withdrawal
resistance (SWR), are highly correlated to the board mean density.
2. The bottom limit of the board density is estimated to be ca. 0.25 g/cm3, based on the correlation regressions between mechanical properties and mean density.
3. At equal mean density level, the MOR and MOE of the conventional particleboards are higher than the homo-profile boards,
due to the higher density near the faces. However, the reverse is true for IB, owing to the presence of the low density core
in the former.
4. The net impact of peak density on MOR and MOE is greater at higher mean density level while raising the core density results
in more pronounced improvement in IB at lower density.
5. In addition to the compaction ratio, the dimensional stability of the board is also affected by the peak area and mat moisture
content.
Received 9 January 1997 相似文献
18.
《Wood material science & engineering》2013,8(1):25-29
Abstract The objective of this work was to evaluate the performance of particleboard manufactured from roselle (Hibiscus sabdariffa) stalks and eucalyptus (Eucalyptus camaldulensis) wood. The manufacturing parameters were various roselle (Hibiscus sabdariffa) ratios in the mixture (0, 25, 50, 75 and 100%) and press time (3, 5 and 7 min). Modulus of elasticity (MOE), modulus of rupture (MOR), internal bonding (IB) strength values and thickness swelling (TS) after 24-hour water soaking of the panels were determined according to the procedure of European Union (EN) Standard. The results of the study demonstrate that roselle stalks can be an alternative raw material source for particleboard industry. With an increase of roselle particles from 0% to 100%, the TS was reduced, and the IB, MOR and MOE were increased. The highest MOE, MOR, IB strength and TS values of the samples were found as 2754.18, 16.81, 0.89 N/mm2 and 15.26% for the panels made using 100% roselle with a 7-min press time, respectively. 相似文献
19.
20.
The objective of this study was to investigate the physical and mechanical performance of flakeboard reinforced with bamboo strips. The study investigated three different bamboo strip alignment patterns and an experimental control. All panels were tested in static bending both along parallel and perpendicular to the lengths of the bamboo strips. Internal bond strength (IB), thickness swelling (TS), linear expansion (LE), and water absorption (WA) were also examined. As expected, modulus of rupture (MOR) and modulus of elasticity (MOE) were substantially greater for all three experimental panel types as compared to the control group. LE was also improved for all three experimental panel groups. The bamboo strip alignment patterns had no significant effect on TS, WA and IB. The sample means for MOR, MOE and LE tested perpendicular to the bamboo strip lengths yielded slightly lower mean values than corresponding samples tested parallel to the bamboo strips lengths. This difference in mechanical properties is largely attributed to low panel density in the failure zones. 相似文献