粉状工业炸药中可燃剂木粉的改性研究

木粉是粉状工业炸药的可燃剂之一，将木粉用氧化剂硝酸或硝酸铵水溶液进行浸泡、烘干处理，得到一种改性木粉。文中研究了改性木粉的制备工艺，测定了改性木粉的性能数据，并将改性木粉应用于膨化硝铵炸药。实验发现应用改性木粉后，膨化硝铵炸药的爆速、猛度和殉爆距离均有明显提高。     

应用锅炉烟道气干燥木粉

木粉为生产硝铵炸药三大原料之一,多数厂采用传统的轮辗机加热翻动的干燥方法,或燃烧炉烟道气气流干燥法干燥木粉。前者是设备利用欠合理,干燥时要有较高的温度,对轮辗机的结构、特别是轴瓦部分有损害,工人的劳动强度较大。后者虽然产量大、质量好,但是能源消耗较大。为了克服以上存在的问题,我厂在硝铵炸药生产中,应用锅炉房的2T锅炉产生的烟道气直接和木粉进行热交换,来达到干燥木粉的目的。一、工艺简述锅炉烟道气经过旋风分离器后,由引风     

PVC/木粉复合体系加工方法与性能的关系

采用开炼机、单螺杆和双螺杆挤出机等加工设备,系统研究了加工过程、混炼工艺等因素对PVC/木粉复合体系的性能和结构的影响。结果表明,添加木粉填料使材料的力学性能降低,但是双辊混炼时,如果先将木粉与CPE混合制备母粒,然后再加到PVC中的母粒法工艺有利于提高材料的力学性能。通过三种混合设备的比较,双螺杆制备的PVC/木粉复合材料的力学性能和流变性能最好,木粉在PVC基体中的分散效果最佳。微观形态观察表明,木粉填料的分散性与加工方法有很大的关系,直接影响了材料的力学性能和流变性能。     

PBS/杨木粉全降解木塑复合材料的加工流变性能及其应用研究

采用高级毛细管流变仪,分别测定PBS及PBS/杨木粉全降解木塑复合材料的流变性能,研究了不同挤出温度、不同木粉含量对复合材料加工性能的影响。以流变性能测试为参考,改变加工工艺,采用熔融共混法制备了PBS/杨木粉全降解木塑复合材料,并测试其性能。结果表明,随着木粉用量的增加,体系流动性明显下降,可加工的温度范围越来越窄,大致木粉填充量每提高5%,需要升高5℃才能保证粘度变化不大;不同加工工艺对所制备的PBS/杨木粉木塑复合材料性能有较大影响;综合流变性能和力学性能,木粉含量为30%、35%、40%、45%和50%的PBS/杨木粉全降解木塑复合材料的较佳加工温度分别为120、125、125、130和135℃。     

木粉聚醚的分子结构表征

报道了用木粉、聚醚及多元醇在催化剂作用下合成新型聚氨酯原材料木粉聚醚，并利用凝胶液相色谱、气相色谱、燃烧热测定等手段证明了化学反应的发生。从反应理论出发推出了木粉聚醚的可能结构，并得到IR、^13C－NMR的验证。结果表明，木粉聚醚是一种多羟基、同时含有糖链和醚链的高聚物。     

木粉干燥过程的数学模型及分析方法

文章通过对木粉干燥过程的水分变化情况进行研究，总结了该过程的数学模型，为生产过程中木粉水分的分析提供了理论参考，同时提供了一种快速方便准确的能适应生产的分析方法。     

原料浸渍工艺对十二醇/木塑复合相变材料影响的研究

以十二醇为相变基元,通过真空浸渍、常压浸渍和超声浸渍等3种工艺使木粉的多孔腔体吸附十二醇,再与聚丙烯共混,制备出十二醇/木塑复合相变材料。通过力学性能测试、差示扫描量热和循环性能分析,研究了不同浸渍工艺对木粉吸附相变剂及复合相变材料综合性能的影响。结果表明:超声浸渍工艺负载十二醇的含量比常压的提高了9.6%,比真空的提高了2.2%。超声处理木粉有利于提高木塑复合相变材料的力学性能,超声浸渍处理后制备的材料相变焓比常压浸渍的提高了6.21J/g。循环测试结果表明,常压浸渍的材料相变焓损失率达到69.17%,而超声浸渍和真空浸渍分别为11.93%和14.97%。     

木粉对吸油型聚氨酯泡沫性能的影响

采用一步法发泡工艺,将可降解的天然植物纤维木粉添加到聚氨酯原料中发泡,成功合成了可降解的高吸油聚氨酯泡沫。研究了木粉含量对聚氨酯泡沫的泡孔结构、拉伸强度、吸油性能、吸水性能和降解性能的影响。结果表明:随着木粉添加量的增加,聚氨酯泡沫的吸油倍率缓慢下降,但是其始终保持了较高的吸油倍率;同时,聚氨酯泡沫的降解性能随着木粉添加量的增加而逐渐提高,并且在磷酸盐缓冲溶液中的失重率要高于土埋法中的失重率,说明木粉的添加有效提高了聚氨酯泡沫的降解性。     

生物质纤维填充聚合物复合材料的界面行为

将木粉和聚合物加入HAAKE流变仪中熔融共混制备了木粉/聚合物复合材料,对比不同木粉预处理方式(碱处理、酸处理)及相容剂改善木粉与聚合物界面相容性的效果。红外光谱(FT-IR)结果表明,碱处理木粉去除了木粉中的小分子物质,酸处理木粉使木粉表面被酯化。木粉碱处理提高了木粉/聚合物复合材料的力学性能,扫描电镜(SEM)照片表明预处理后木粉与聚合物间的相容性得到了改善。使用合适的相容剂也可以改善木粉与聚合物的相容性,提高复合材料的力学性能。同时相容剂和碱处理木粉及酸处理木粉存在协同效应。     

木粉对聚乳酸流变、结晶及发泡行为的影响

以超临界CO_2为发泡剂,设计高温保压、低温快速泄压发泡的工艺,制备微孔发泡木粉/聚乳酸复合材料。利用X射线衍射仪、差示扫描量热仪、旋转流变仪对复合体系结晶及流变性能进行分析。采用排水法及扫描电镜研究了木粉含量对发泡材料表观密度、发泡倍率,泡孔密度及泡孔形貌的影响。结果表明,木粉的加入提高了木粉/聚乳酸复合材料熔体的复数黏度和储能模量,降低了聚乳酸的结晶度,提高了泡孔密度,减小了泡孔尺寸。当木粉含量为20%时,木粉/聚乳酸发泡材料表观密度为0.19g/cm~3,发泡倍率达到7倍,泡孔密度为7.23×10~8 cm~(-3),平均泡孔直径为20μm。     

Poly(vinyl chloride)–wood flour press mould composites: The influence of raw materials on performance properties

In this paper is described an approach to the study of the influence of the nature and the composition on the performance properties of wood flour/poly(vinyl chloride)(PVC) composites. The raw materials were mixed on a two-roll mill. The final composites were obtained by controlled press moulding. The results indicate that properties such as surface tension and flexibility do not change significantly with the composition in the chosen composition range. The colour is easily controlled by variation in the content and the type of wood flour. A thermal and morphological study has been performed on the raw materials and on the composites to assess the effect of wood flour on the stability of the composites. The inclusion of wood flour into PVC leads to poorer tensile properties. This effect is related to the lack of association between the wood flour and the PVC.     

毛白杨木粉/聚丙烯复合材料界面相容性的介电弛豫解析

为解析木塑复合材料的界面相容性机制,通过介电弛豫过程分析研究不同硅烷偶联剂添加量的毛白杨木粉/聚丙烯复合材料的温度谱及频率谱,并计算介电弛豫过程中的表观活化能和热力学量。结果表明:在添加硅烷偶联剂的毛白杨木粉/聚丙烯复合材料中能观察到基于木材细胞壁无定形区中伯醇羟基的回转取向运动的弛豫过程;弛豫强度随硅烷偶联剂添加量增大先减少而后缓慢增大;随偶联剂添加量的增大,弛豫时间分布峰呈先变宽、变低,然后再变尖、变高趋势;表观活化能、活化焓、活化自由能和活化熵随硅烷偶联剂添加量增加先增大后减小。表观活化能在硅烷偶联剂添加量(质量比)为2.0%时达到最大值(28.12kJ/mol),与未添加偶联剂的毛白杨木粉/聚丙烯复合材料的(13.86kJ/mol)相比增加2倍以上,活化焓在硅烷偶联剂添加量从0%时的12.09kJ/mol增大到2.0%时的26.35kJ/mol,增大了117.9%,说明弛豫过程中伯醇羟基回转取向运动需要克服的能垒增加,毛白杨木粉与聚丙烯塑料的相容性更好,结合更紧密,界面强度更强,性能更加稳定。     

A new method of making particleboard with a formaldehyde-free soy-based adhesive

A soy-based formaldehyde-free adhesive consisting of soy flour (SF) and a curing agent (CA) has been successfully used for the production of plywood. However, this adhesive cannot be easily sprayed onto wood particles for making particleboard because of its high viscosity. The following new method of using this adhesive was developed and investigated. SF was first mixed with water to form dilute soy slurry that could be easily coated onto wood particles. The soy-coated wood particles were dried to certain moisture content and then further coated with an aqueous curing agent. Effects of particleboard density, adhesive usages for both core and face particles, the solids content of the soy slurry, hot-press time, hot-press temperature, the storage time of the wet soy-coated wood particles, and the SF/CA weight ratio on the internal bond strength (IB), the modulus of rupture (MOR), and the modulus of elasticity (MOE) of particleboard were investigated.     

Influence of wood flour moisture content on the degree of silane-crosslinking and its relationship to structure–property relations of wood–thermoplastic composites

The objective of this work was to examine how the moisture content of wood flour affects the degree of crosslinking when producing silane-crosslinked wood–thermoplastic composites. Crosslinked composites were produced by adding a silane solution to the compounding process of wood flour and polyethylene. Crosslinked composites of pre-dried as well as non-dried wood flour were prepared and their degree of crosslinking at various storage conditions was determined. Mechanical properties and the creep response of the crosslinked composites were tested in order to establish structure–properties relations. The results showed that all crosslinked composites displayed higher strengths and lower creep responses compared with non-crosslinked control samples. However, the degree and rate of crosslinking proved to be lower when a larger amount of moisture was present in the compounding process. It was concluded that the silane-grafting yield was lower when wood flour of a higher moisture content was used.     

Plastic-like moulded products made from renewable forest resources

The bark of fast-growing wood species such as Pinus and Acacia species contains a high amount of tannin, a renewable forest resource. In this study, the possibility of utilizing radiata pine tannin as a substitute for synthetic thermosetting resins in the production of moulded products was investigated. When tannin powder and wood flour (tannin : wood flour = 1 : 1 w/w) were mixe and moulded at 190 °C and 100 MPa for 10 minutes, plastic-like moulded products with a modulus of elasticity (MOE) of 9 to 10 GPa and a modulus of rupture (MOR) of 60 to 70 MPa were obtained without further additives. Furthermore, when tannin and wood flour (1 : 1 w/w) were mixed in water and freeze-dried, tannin was partially impregnated into the wood flour, and the MOR of the moulded product increased by more than 10% compared with that of products produced without the impregnation process. The moulded products described above showed good water resistance. Moreover, an increase in wood flour content was found to upgrade the mechanical properties effectively, with a MOR of 90 to 100 MPa being obtained at 75% wood content, despite a reduction in water resistance.     

多孔材料用于木材干燥过程中VOCs吸附的研究进展和探讨

木材干燥过程中会产生一系列有机挥发性气体(VOCs),这些气体对人体和环境都会带来巨大的危害。加强对木材干燥过程中产生VOCs的释放过程、释放控制和吸附的研究,即寻求环保高效的吸附剂是当前国内外研究的热点之一。在总结活性碳、活性碳纤维、活性碳纳米纤维、分子筛和蒙脱石基介孔材料等对VOCs吸附研究的基础上,探讨了新型MOFs材料在木材干燥工业过程中释放VOCs的应用可行性和发展前景。     

Date palm wood flour/glass fibre reinforced hybrid composites of recycled polypropylene: Mechanical and thermal properties

Recycled polypropylene (RPP) based hybrid composites of date palm wood flour/glass fibre were prepared by different weight ratios of the two reinforcements. Mixing process was carried out in an extruder and samples were prepared by injection molding machine. Recycled PP properties were improved by reinforcing it by wood flour. The tensile strength and Young’s modulus of wood flour reinforced RPP increased further by adding glass fibre. Glass fibre reinforced composites showed higher hardness than other composites. Morphological studies indicated that glass fiber has good adhesion with recycled PP supporting the improvement of the mechanical properties of hybrid composites with glass fiber addition. Addition of as little 5 wt% glass fibre to wood flour reinforced RPP increases the tensile strength by about 18% relative to the wood flour reinforcement alone. An increase in wood particle content in the PP resulted in a decrease in the degree of crystallinity of the polymer. The tensile strength of the composites increased with an increase in the percentage of crystallinity when adding the glass fibre. The improvement in the mechanical properties with the increase in crystallinity percentage (and with the decrease of the lamellar thicknesses) can be attributed to the constrained region between the lamellae because the agglomeration is absent in this case.     

离子聚合物改性木粉/HDPE复合材料流变特性

为了提高木塑复合材料（WPC）的加工流动性能,利用离子聚合物改性WPC,通过HAAKE Minilab微量混合流变仪研究了离子聚合物改性木粉/高密度聚乙烯（HDPE）的毛细管流变特征。结果表明：添加与未添加离子聚合物的木粉/HDPE均为非牛顿流体中的假塑性流体,均呈现出“剪切变稀”的效应;随着钠离子聚合物含量的增加,改性木粉/HDPE的剪切应力和表观黏度均随着剪切速率的增大呈现降低的趋势,表明钠离子聚合物的加入可以显著改善聚合物熔体的流动特性;添加4wt%的钠离子聚合物和4wt%的锌离子聚合物的木粉/HDPE剪切应力和表观黏度均要低于添加4wt%的偶联剂马来酸酐接枝聚乙烯（MAH-g-PE）的WPC的值,表明与MAH-g-PE相比,离子聚合物更能够改善WPC的流动性能,减小熔体流动时HDPE与木粉之间的摩擦阻力;SEM分析表明,添加离子聚合物后HDPE塑料对木粉有很好的包覆效果,没有明显的界面缝隙,且在WPC断面上存在大量的毛刺纤维。     

滑石粉对微孔发泡木粉/聚丙烯复合材料结晶行为及泡孔结构的影响

以滑石粉为成核剂,超临界CO_2为发泡剂,采用间歇釜式方法制备微孔发泡木粉/聚丙烯复合材料。采用DSC、XRD和SEM对微孔发泡木粉/聚丙烯复合材料的结晶行为与泡孔结构进行了测定与分析。结果表明:滑石粉的添加能够提高微孔发泡木粉/聚丙烯复合材料的结晶温度,诱导产生不完善的α晶型;能够提高聚合物基体的熔体黏度,减小泡孔尺寸,增加泡孔密度,促使泡孔尺寸分布更均匀,最终能够形成泡孔密度为1.0×10~9个/cm~3、平均泡孔半径为16.4μm、发泡倍率为18倍、表观密度约为0.055g/cm~3的微孔发泡木粉/聚丙烯复合材料。     

硅烷偶联剂改性的木粉/P34HB复合包装材料的制备

目的研究硅烷偶联剂KH550含量对木粉/P34HB复合包装材料性能的影响。采用KH550改性木粉,提高与聚(3-羟基丁酸酯-4-羟基丁酸酯)(P34HB)的结合强度,改善复合材料的力学性能和界面相容性。方法以KH550为改性剂,木粉和P34HB为原料,利用共混热压工艺制备改性木粉/P34HB复合材料;通过对复合材料的形貌进行观察,以及傅里叶变换红外光谱(FTIR)、热重分析(TGA)和力学性能分析,研究KH550质量分数不同时对复合材料界面相容性、力学性能和热性能的影响。结果添加KH550后,复合材料的的界面相容性得到改善;FTIR分析表明,KH550已经成功接枝到木粉中;适量的KH550提高了复合材料的热稳定性;复合材料的储能模量增加;复合材料的力学性能也有所提高。此外还得到了最佳的KH550添加量,即质量分数为0.5%。结论 KH550不仅使得木粉与P34HB的相容性得到改善,同时也增强了复合包装材料的力学性能和热性能。