低表面能材料粘接研究进展

吴雯晓¹，张承钰¹，杨智慧¹，史浩伯²，田伟智²，孙方皓¹，吴连锋³，卢海峰¹

（1.山东大学化学与化工学院，山东济南250100；2.北京星航机电装备有限公司，北京100074；3.海洋涂料国家重点实验室，海洋化工研究院有限公司，山东青岛266071)

【摘  要】低表面能材料在赋予其重要的应用价值的同时也带来了难以粘接的问题。本文从低表面能材料粘接困难的原理出发，总结了近年来国内外在提高低表面能材料粘接性能方面的研究进展，涵盖了低表面能材料的表面物理处理方法（如机械物理处理、等离子体处理、电晕处理和辐照处理）、表面化学处理方法（如火焰处理、化学刻蚀处理、接枝处理、底涂剂处理）、物理方法与化学方法复合处理以及在不加以表面处理的前提下直接进行粘接的胶粘剂种类研究和探索等。最后对相关研究的未来发展进行展望。

【关键词】低表面能材料；表面改性；胶粘剂

醋酸乙烯酯对聚丙烯酸酯压敏胶性能的影响

张 鑫，黄  鹤

（苏州大学材料与化学化工学部，新型功能高分子材料国家地方联合工程实验室，江苏 苏州   215123）

【摘 要】醋酸乙烯酯是介于传统的丙烯酸酯软、硬单体之间的一类中间单体，常常用于聚丙烯酸酯压敏胶的制备中，但通过改变醋酸乙烯酯的量来调节丙烯酸酯压敏胶的性能尚无系统的研究报道。为此，本文通过中间单体醋酸乙烯酯与传统的丙烯酸酯软、硬单体的溶液共聚合，制备了聚丙烯酸酯压敏胶。详细研究了中间单体醋酸乙烯酯对聚丙烯酸酯压敏胶性能的影响，并与传统的硬单体甲基丙烯酸甲酯进行了对比。研究结果表明：⑴随着醋酸乙烯酯用量的增大，压敏胶的内聚力增大，与基材的黏附性降低。当醋酸乙烯酯用量达9.5%时，呈现界面破坏，剥离强度能达到18.78 N/25 mm，此时持粘力、初粘力分别为1.10 h、4#球。⑵相对于传统的硬单体甲基丙烯酸甲酯，中间单体醋酸乙烯酯的使用，对压敏胶的初粘力及持粘力贡献都没有优势，但可提高剥离强度达20%左右。

【关键词】溶液聚合；聚丙烯酸酯；压敏胶；醋酸乙烯酯

添加高岭土对木质素基酚醛树脂胶粘剂储存稳定性的研究

庄军平，黄  睿，刘宇旗

（华南理工大学轻工科学与工程学院，广东 广州 510640）

【摘  要】木质素作为一种经济、易获取的可再生生物资源，可部分替代苯酚生产木质素基酚醛树脂（LPF）。但替代苯酚与甲醛反应的产物大分子结构相较于纯酚醛树脂（PF）更加复杂，易发生团聚，使得LPF的储存稳定性低。为克服这一难题，本研究在LPF制备过程中添加高岭土制备高岭土-木质素基酚醛树脂（K-LPF），以储存时间和胶合特性为主要评价指标，采用正交设计法对影响K-LPF储存稳定性的主要因素进行了优化。研究结果表明：⑴添加高岭土作为胶粘剂的稳定剂，可有效提高储存稳定性。采用正交设计法确定的最佳工艺条件为：木质素替代率60%，碱用量25%，在第3批加料时加入6%的高岭土，所得胶粘剂的胶合强度为1.33 MPa，储存时间可达98 d，且各项指标均能满足GB/T 14732—2017标准中的要求。极差分析表明，影响储存时间的主要因素的主次顺序为：碱用量>木质素替代率>高岭土添加量>高岭土添加批次。⑵红外光谱（FT-IR）和热重分析（TG）结果表明，添加高岭土制备的K-LPF与LPF和PF红外谱图类似，均具有相近的结构，表明高岭土和木质素以共聚的方式与苯酚和甲醛参与反应，降低胶粘剂中有机大分子因自聚而发生的沉淀，提高其储存稳定性。⑶验证试验表明，实际试验结果符合正交设计法的预测，进一步证明了以上优化所得最佳工艺条件的有效性和可靠性，为制备储存稳定性高的K-LPF提供了理论和实践依据。

【关键词】木质素基酚醛树脂；高岭土；正交设计；胶合强度；储存稳定性

氮化硼用量对丙烯酸酯胶粘剂基氮化硼/松木粉末复合板性能的影响

刘  妹¹，葛冰洁¹，戚安杰¹，于竹青¹，项尚林^1,2

(1.南京工业大学材料科学与工程学院，江苏南京  211816；2.山东力合新材料科技有限公司，山东济宁  272200）

【摘  要】氮化硼（BN）因其优异的导热性和化学稳定性成为提高复合材料热传导性能的理想填料，而丙烯酸酯胶粘剂尽管存在诸多优点，但热传导性能相对较差、不耐高温，从而限制了其在高温环境下的应用。本文在丙烯酸酯胶粘剂中引入导热填料氮化硼，通过制备工艺简单的方法——直接热压法制备了丙烯酸酯胶粘剂基氮化硼/松木粉末复合板（BN/SMF复合板）。研究了氮化硼用量对BN/SMF复合板导热性能、硬度、抗冲击性能以及阻燃等性能的影响。研究结果表明：⑴傅里叶变换红外光谱测试表明，丙烯酸酯胶粘剂固化反应完全。⑵随着氮化硼用量增加，BN/SMF复合板的导热系数也相应增加。⑶无机成分氮化硼在高温下不易分解，且能起到很好的物理阻隔作用，提高了BN/SMF复合板的分解温度。⑷随着氮化硼用量的增加，BN/SMF复合板的冲击强度和硬度都会增加。但当氮化硼用量达到一定值时，由于粒子团聚，破坏了复合基体的连续性，冲击强度和硬度都下降。⑸随着氮化硼用量增加，BN/SMF复合板的热传导性能、阻燃性能均有所提高。

【关键词】氮化硼；丙烯酸酯胶粘剂；复合板；导热性能

高耐润滑油红外与激光兼容涂层的制备及性能研究

吕丹丹¹，杨  聪¹，张伟钢¹，乔  智²，孔祥兵²

（1.滁州学院，安徽 滁州  239000；2.安徽徽邦漆业有限公司，安徽 天长  239311）

【摘  要】具有突出耐润滑油性能的红外与激光兼容涂层广泛应用在各类飞行器多频谱兼容隐身领域，且应用前景广阔，是隐身材料领域的研究热点。本文采用绢云母改性方法，制备得到了一种具有突出耐润滑油性能的复合涂层[(PU)/Al-Sm₂O₃]，并系统地研究了涂层的理化性能变化规律。研究结果表明：绢云母改性后的涂层表面微观结构依然十分规整，PU树脂对涂层中颜/填料的包覆依然紧密，微观结构保持稳定。绢云母改性可明显改善涂层的规整度、致密度和片状铝粉的排布状态，促使涂层发射率显著降低，涂层对润滑油腐蚀的稳定性得到显著提高。绢云母改性可明显提高涂层的耐冲击强度，可使涂层在长时间的润滑油腐蚀过程中仍然保持在最优状态。

【关键词】涂层；绢云母；红外与激光兼容；耐润滑油性能

超临界CO₂处理对芳纶纤维复合材料界面性能的影响研究

李亚锋^1,2，张杜鹃^1,2，鹿海军^1,2

（1.中国航空制造技术研究院复合材料技术中心，北京  101300；2.先进复合材料国防科技重点实验室，北京  100095）

【摘  要】芳纶纤维是一种高性能纤维，在复合材料领域具有广泛的应用。但由于其表面具有化学惰性，与树脂基体的界面粘接性不佳，并且在制备纤维的过程中常在纤维织物表面残留杂质，从而影响纤维/树脂之间的结合性。本文通过超临界CO₂流体对两种芳纶纤维（K49和F-12）表面进行处理，并研究了超临界CO₂流体对纤维织物（F-12F）表面的影响。然后以处理后的芳纶纤维及纤维织物为原料，制备了芳纶纤维增强环氧树脂复合材料，对复合材料的弯曲性能和层间剪切性能进行了研究。研究结果表明：⑴超临界CO₂处理对K49和F-12纤维的拉伸性能无明显影响，但对纤维的表面起到有效的清洗效果，表面的杂质元素含量明显降低。⑵经过超临界CO₂处理后，K49纤维的表面粗糙度增加，F-12纤维的整体表面粗糙度反而有所下降。经过超临界CO₂处理后，K49纤维/树脂间的界面剪切强度提高了40.8%，纤维/树脂的结合性有明显改善，而F-12纤维/树脂间的界面剪切强度略有降低。⑶超临界CO₂处理前后芳纶纤维/环氧复合材料（K49/5224A和F-12/5224A）的弯曲性能、层间剪切性能的变化均在10%范围内，超临界处理对两种芳纶纤维增强复合材料的弯曲、剪切宏观力学性能无明显影响。而对于F-12纤维织物而言，超临界CO₂处理可有效地去清除纤维在编织过程中产生的杂质，提高纤维织物/树脂界面结合性。

【关键词】芳纶纤维；超临界CO₂；表面处理

低温表干快的聚氨酯密封胶的研制

招兆林，郭  盟，韦欣照，江  虹

（广东普赛达材料科技股份有限公司，广东 东莞  523646）

【摘  要】为满足生产节奏的不断加快，发展低温快干快固的单组分聚氨酯密封胶是最重要的趋势之一。本研究制备了一种低温表干快的单组分聚氨酯密封胶，讨论了增塑剂的相对分子质量、不同伯羟基含量的聚醚多元醇、两种催化剂的不同量搭配及两种预聚体的不同配比对密封胶低温表干时间及固化速度的影响。研究结果表明：⑴不同相对分子质量的增塑剂对单组分聚氨酯密封胶的固化速度有影响，相对分子质量越小，固化速度越大。考虑增塑剂的迁移性，增塑剂的相对分子质量在270~350之间较为合适。⑵聚醚多元醇的伯羟基含量越大，对单组分聚氨酯密封胶的低温表干时间及固化速度提升越大。结合伯羟基对树脂相容性的影响，选取伯羟基含量为20%的聚醚多元醇相对最优。⑶二吗啉二乙基醚（DMDEE）添加0.15%、二月桂酸二丁基锡（DBTDL）添加0.05%时，低温表干时间相对最快，固化速度也最快。⑷使用4,4'-二苯基甲烷二异氰酸酯（MDI）制备的预聚体与使用甲苯二异氰酸酯（TDI）制备的预聚体搭配使用，可以提升密封胶的表干时间及固化速度。当两者添加量分别为25%和10%时，其保证了低温表干时间较快的同时不降低固化速度。

【关键词】聚氨酯；密封胶；表干快；低温

环氧胶粘剂的低温贮存性能研究

安东澜，李永亮，邸安乐，马  丽，贺  华，黄  涛

（航空工业西安飞行自动控制研究所，陕西 西安  710065）

【摘  要】环氧树脂与固化剂混合后普遍开始固化反应，因此存在适用期短、贮存困难等问题。有必要建立一种快速可靠的低温贮存性能评估方法，以便对所有环氧固化体系进行快速验证，使之能在结果可靠的前提下降低试验成本。本研究以两种不同的环氧固化体系为研究对象，在不同温度下对黏度进行表征，按Arrhenius方程拟合，推导出凝胶时间和贮存温度之间的关系，最后根据贮存要求设计了合理贮存温度。研究结果表明：⑴黏度和凝胶时间测试结果表明：在-80 ℃的贮存温度下，间苯二甲胺固化体系和咪唑固化体系到达贮存期时性能和新配胶相比差异不大，均优于原-20 ℃贮存胶到达贮存期时的性能。⑵剪切强度测试结果表明：两种固化体系下-80 ℃贮存胶在到达贮存期时剪切强度满足要求，高于-20 ℃贮存胶，且和新配胶性能基本一致。⑶在间苯二甲胺固化体系下，-20 ℃贮存的胶剪切强度略低于指标要求，存在使用风险；在咪唑固化体系下，-20 ℃贮存胶的剪切强度满足指标要求。

【关键词】环氧胶粘剂；低温；贮存期；凝胶时间

耐高温RTV-1硅酮密封胶的性能研究

蒙嘉华¹，陈炳耀²，林志鹏¹，郭仕川¹，董  颖¹

(1.广东三和控股有限公司，广东 中山  528400；2.中山市珉和化工科技有限公司，广东 中山  528400)

【摘  要】本研究以α,ω-端羟基二甲基硅氧烷(107硅橡胶)为主原料，添加硅微粉、纳米碳酸钙和气相法二氧化硅等填料，并加以交联剂、硅烷偶联剂、催化剂和耐热添加剂，制得室温固化单组分耐高温硅酮密封胶。探讨了配方中不同黏度的107硅橡胶配比及含量、不同配比的填料以及耐热添加剂种类对硅酮密封胶粘接性能和耐热性能的影响。研究结果表明：⑴不同黏度的107硅橡胶配比对硅酮密封胶性能的影响研究中发现，当高黏度107硅橡胶的质量分数占比较高时，制得的硅酮硅密封胶的断裂伸长率也较高，但其拉伸强度、硬度则较低，且表干时间偏慢。⑵选择黏度为80 000 mPa·s的107硅橡胶与20 000 mPa·s的107硅橡胶等比例进行添加，且总添加量在50份时，室温拉伸强度为2.51 MPa，断裂伸长率可达到407%，且其耐高温性能较佳。⑶不同配比的碳酸钙与硅微粉对硅酮密封胶的粘接性能及耐温性能均有较大影响。随着碳酸钙比例的增加，硅酮密封胶对基材的粘接力值也逐步加大，但力值增加的幅度逐渐减小；相比于金属基材，硅酮密封胶对塑料基材的粘接性更加牢固。碳酸钙与硅微粉常用作硅酮密封胶的填料，硅微粉相比于碳酸钙，在一定程度上可提高硅酮密封胶的耐温性能。⑷耐热添加剂中的金属氧化物，可以在不同程度上提高硅酮密封胶的耐热性能。

【关键词】硅酮密封胶；耐高温；107硅橡胶；硅微粉；耐热添加剂

含氟聚氨酯预聚物的合成

安靖怡¹，张天福²，张孝阿¹，王成忠¹，江盛玲¹，张军营¹

（1.北京化工大学，碳纤维及功能高分子教育部重点实验室，材料科学与工程学院，北京 100029；2.航天化学动力技术国防科技重点实验室，湖北航天化学技术研究所，湖北 襄阳 441003）

【摘  要】为解决常规聚醚或聚酯含氟化合物简单共混相容性差的问题，本文以叠氮聚醚二元醇和含氟聚醚二元醇为初始原料，根据异佛尔酮二异氰酸酯（IPDI）中异氰酸酯基团的活性差异，通过分步预聚法，设计合成了系列含氟聚氨酯预聚物。研究了叠氮聚醚二元醇的添加方式、催化剂种类、反应温度、反应时间对第一步预聚反应的影响以及反应时间对第二步预聚反应的影响。研究结果表明：预聚反应的最佳条件为，叠氮聚醚二元醇以滴加的方式引入反应体系，在25℃、二月桂酸二丁基锡的催化下反应1 h，随后引入含氟聚醚二元醇（PEG-45）于80 ℃下反应4 h。反应成功合成了含氟聚氨酯预聚物。

【关键词】含氟聚氨酯；预聚物；异氰酸酯基团活性差异

水热法制备三维海胆型TiO₂微纳米材料及其表征

柳  咪¹，来  贤²

（1.广州科技职业技术大学，广东 广州  510550；2.陕西科技大学，陕西 西安  710021）

【摘  要】具有特殊形貌和结构的二氧化钛（TiO₂）微纳米材料近年来成为关注和研究的热点，而如何通过水热法精确控制TiO₂的形貌仍然是一大挑战。通过一步水热法，采用四异丙醇钛（TTIP）作为高效的钛源，同时巧妙地引入浓盐酸与聚乙烯吡咯烷酮（PVP）作为形貌调控剂，在乙二醇这一绿色溶剂的环境下制备了海胆型TiO₂微纳米材料。探讨了不同反应条件对TiO₂结构与性能的影响，并分析其生长机理。研究结果表明：水热法可以成功制备出三维海胆型TiO₂微纳米材料，且反应条件对材料的形貌和性能有重要影响。此外，在优化条件下，当PVP的浓度设定为6 mg/mL，同时操作温度控制在150 ℃，并维持反应时间长达24 h时，样品的分散性能达到最优状态，且其表面形貌的完整性得到显著提升。

【关键词】水热法；海胆型TiO₂；微纳米材料；制备；表征

Research progress on bonding of low surface energy materials

Wu Wenxiao¹, Zhang Chengyu¹, Yang Zhihui¹, Shi Haobo²,

Tian Weizhi², Sun Fanghao¹, Wu Lianfeng³, Lu Haifeng¹

(1.School of Chemistry and Chemical Engineering, Shandong University, Ji'nan 250100, Shandong, China; 2.Beijing Xinghang Mechanical-Electric Equipment Co., Ltd., Beijing  100074, China; 3.State Key Laboratory of Marine Coatings, Marine Chemical Research Institute Co., Ltd., Qingdao  266071, Shangdong, China)

【Abstract】Low surface energy materials endow significant application values while also bringing about the problem of difficult bonding. Starting from the principle of difficulty in bonding low surface energy materials, the research progress in improving the bonding performance of low surface energy materials at home and abroad in recent years was summarized in this paper, covering surface physical treatment methods for low surface energy materials (such as mechanical physical treatment, plasma treatment, corona treatment, and irradiation treatment), surface chemical treatment methods (such as flame treatment, chemical etching treatment, grafting treatment, primer treatment), combined treatment of physical and chemical methods, as well as research and exploration of adhesive types for direct bonding without surface treatment. Finally, future development prospects for related research were proposed.

【Keywords】low surface energy materials; surface modification; adhesive

Effect of vinyl acetate on the performance of polyacrylate pressure-sensitive adhesive

Zhang Xin, Huang He

(College of Chemistry, Chemical Engineering and Materials Science of Soochow University, State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Suzhou 215123, Jiangsu, China)

【Abstract】Vinyl acetate is a kind of intermediate monomer between traditional soft and hard acrylate monomers, and is often used in the preparation of polyacrylate pressure-sensitive adhesive. However, there is no systematic study report on adjusting the performance of polyacrylate pressure-sensitive adhesive by changing the amount of vinyl acetate. Therefore, in this paper, polyacrylate pressure-sensitive adhesive was prepared by solution copolymerization of intermediate monomer vinyl acetate with traditional soft and hard acrylate monomers. The effect of intermediate monomer vinyl acetate on the performance of polyacrylate  pressure-sensitive adhesive was studied in details and it was compared with that of the traditional hard monomer methyl methacrylate. The research results showed that,⑴ As the amount of vinyl acetate increased, the cohesion of pressure-sensitive adhesive increased, and the adhesion to the substrate decreased. When the amount of vinyl acetate reached 9.5%, interface failure occurred, and the peel strength could reach 18.78 N/25 mm. At this time, the holding power and initial tack were 1.10 h and 4# ball, respectively. ⑵ Compared to traditional hard monomer methyl methacrylate, the use of intermediate monomer vinyl acetate had no advantage in contributing to the initial tack and holding power of pressure-sensitive adhesive, but could increase the peel strength by about 20%.

【Keywords】solution polymerization; polyacrylate; pressure-sensitive adhesive; vinyl acetate

Study on storage stability of lignin-based phenolic resin adhesive by adding kaolin

Zhuang Junping, Huang Rui, Liu Yuqi

(School of Light Industry and Engineering, South China University of Technology, Guangzhou510640, Guangdong, China)

【Abstract】Lignin, as an economical, easily accessible, and renewable bio-resource, can partially replace phenol in the production of lignin-based phenolic resin (LPF). However, the macromolecular structure of the product from the reaction between substituted phenol and formaldehyde is more complex compared to pure phenolic resin (PF), leading to easy agglomeration and low storage stability of LPF. In order to address this challenge, kaolin was added during the preparation of LPF to develop kaolin-lignin-based phenolic resin (K-LPF). Using storage time and bonding properties as main evaluation indicators, the orthogonal design method was employed to optimize the main factors affecting the storage stability of K-LPF. The research results showed that, ⑴ The addition of kaolin as a stabilizer of adhesive effectively enhanced the storage stability. The optimal process conditions determined by orthogonal design method were: lignin substitution rate of 60%, alkali dosage of 25%, and addition of 6% kaolin during the third batch of feeding. The bonding strength of the adhesive obtained was 1.33 MPa, and the storage time could reach 98 days, with all indicators meeting the requirements of GB/T 14732—2017 standard. The range analysis revealed that the main factors affecting storage stability followed the order: alkali dosage > lignin substitution rate > kaolin addition amount > kaolin feeding batch. ⑵ Infrared spectroscopy (FT-IR) and thermogravimetric (TG) analysis indicated that the K-LPF prepared by adding kaolin had similar structures to LPF and PF in infrared spectra, suggesting that kaolin and lignin participated in the reaction with phenol and formaldehyde through copolymerization. It reduced the precipitation of organic macromolecules caused by self-polymerization, thereby improving its storage stability. ⑶ The verification experiment showed that the actual experimental results conformed to the prediction of orthogonal design method, further proving the effectiveness and reliability of the optimized process conditions obtained above, providing theoretical and practical basis for the preparation of K-LPF with high storage stability.

【Keywords】lignin-based phenolic resin;kaolin; orthogonal design; bonding strength; storage stability

Effect of boron nitride dosage on the properties of acrylate adhesive-based boron nitride/pine wood powder composite panels

Liu Mei¹, Ge Bingjie¹, Qi Anjie¹, Yu Zhuqing¹,Xiang Shanglin^1,2

(1.School of Materials Science and Engineering, Nanjing Tech University, Nanjing 211816, Jiangsu, China; 2.Shandong Lihe New Material Technology Co., Ltd., Jining 272200, Shandong, China)

【Abstract】Boron nitride (BN), due to its excellent thermal conductivity and chemical stability, has become an ideal filler for enhancing the thermal conductivity of composite materials. Although acrylate adhesive has many advantages, it has relatively poor thermal conductivity and is not resistant to high temperature, which restricts its application in high-temperature environment. In this paper, the thermally conductive filler boron nitride was introduced into the acrylate adhesive, and the acrylate adhesive-based boron nitride/pine wood powder composite panels (BN/SMF composite panels) were prepared by the simple preparation process, namely the direct hot pressing method. The effects of the amount of boron nitride on the thermal conductivity, hardness, impact resistance, and flame retardancy of BN/SMF composite panels were studied. The research results showed that, ⑴Fourier transform infrared spectroscopy testing indicated that the curing reaction of acrylate adhesive was complete. ⑵ With the increase in the amount of boron nitride, the thermal conductivity coefficient of BN/SMF composite panels also increased accordingly.⑶ The inorganic component boron nitride was not easy to decompose at high temperature and could play an excellent physical barrier role, thus increasing the decomposition temperature of BN/SMF composite panels. ⑷ As the amount of boron nitride increased, the impact strength and hardness of BN/SMF composite panels increased. However, when the amount of boron nitride reached a certain value, due to the agglomeration of particles, the continuity of the composite matrix was disrupted, and both the impact strength and hardness decreased. ⑸ With the increase in the amount of boron nitride, both the thermal conductivity and flame retardancy of BN/SMF composite panels were improved.

【Keywords】boron nitride;acrylate adhesive; composite panel; thermal conductivity

Preparation and properties of infrared and laser compatible coating with high lubricating oil resistance

Lyu Dandan¹, Yang Cong¹, Zhang Weigang¹, Qiao Zhi², Kong Xiangbing²

(1. Chuzhou University, Chuzhou 239000, Anhui, China; 2. Anhui Huibang Paint Industry Co., Ltd., Tianchang  239311, Anhui, China)

【Abstract】Infrared and laser compatible coating with outstanding lubricating oil resistance has been widely applied in multi-spectral compatible stealth fields for various aircrafts, demonstrating broad application prospects and currently constituting a research hotspot in stealth materials. Using the sericite modification method, a kind of composite coating [(PU)/Al-Sm₂O₃] with outstanding lubricating oil resistance was prepared in this paper, and the changes in the physical and chemical properties of the coating were studied systematically. The research results showed that, the microstructure of the coating surface modified with sericite was still very regular, and the PU resin still tightly wraped the pigment/filler in the coating, maintaining a stable microstructure. Modification of sericite could significantly improve the regularity, density, and arrangement of flake aluminum powder in the coating, leading to a significant decrease in coating emissivity and a significant improvement in the stability of coating against lubricating oil corrosion. Modification of sericite could significantly improve the impact strength of the coating, allowing it to remain in its optimal state even during prolonged lubricating oil corrosion process.

【Keywords】coating; sericite; infrared and laser compatible; lubricating oil resistance

Study on the effect of supercritical CO₂ treatment on the interface properties of aramid fiber composite materials

Li Yafeng, Zhang Dujuan, Lu Haijun

(1. Composite Technology Center, AVIC Manufacturing Technology Institute, Beijing 101300, China; 2. National Key Laboratory of Advanced Composites, Beijing  100095, China)

【Abstract】Aramid fiber is a high-performance fiber that has a wide range ofapplication in the field of composite materials. However, due to its chemically inert surface, its interface adhesion with the resin matrix is poor, and impurities often remain on the surface of fiber fabric during the fiber preparation process, which affects the bonding between the fiber and resin. The surface treatment of two kinds of aramid fibers (K49 and F-12) using supercritical CO₂ fluid was investigated in this paper, and the effect of supercritical CO₂ fluid on the surface of fiber fabrics (F-12F) was also studied. Then, using processed aramid fibers and fiber fabrics as raw materials, aramid fiber-reinforced epoxy resin composite materials were prepared, and the flexural and interlaminar shear properties of composite materials were studied. The research results showed that, ⑴ Supercritical CO₂ treatment had no significant effect on the tensile properties of K49 and F-12 fibers, but it effectively cleaned the surface of fibers and significantly reduced the content of impurity elements on the surface. ⑵ After supercritical CO₂ treatment, the surface roughness of K49 fiber increased, while the overall surface roughness of F-12 fiber decreased. After supercritical CO₂treatment, the interfacial shear strength between K49 fiber and resin increased by 40.8%, and the bonding between fiber and resin was significantly improved, while the interfacial shear strength between F-12 fiber and resin slightly decreased. ⑶ The changes in flexural and interlaminar shear properties of aramid fiber/epoxy composites (K49/5224A and F-12/5224A) before and after supercritical CO₂treatment were within 10% range. Supercritical treatment had no significant effect on the flexural and shear macroscopic mechanical properties of the two aramid fiber-reinforced composites. For F-12 fiber fabrics, supercritical CO₂treatment could effectively remove impurities generated during the weaving process and improved the interfacial bonding between fiber fabric and resin.

【Keywords】aramid fiber; supercritical CO₂; surface modification

Development of polyurethane sealant with fast surface drying at low temperature

Zhao Zhaolin, Guo Meng, Wei Xinzhao, Jiang Hong

(Guangdong Pustar Adhesives and Sealants Co., Ltd., Dongguan 523646, Guangdong, China)

【Abstract】To meet the constantly accelerating production pace, the development of single-component polyurethane sealant with fast drying and fast curing at low temperature is one of the most important trends. A single-component polyurethane sealant with fast surface drying at low temperature was prepared in this paper, and the effects of the relative molecular weight of plasticizers, polyether polyols with different primary hydroxyl contents, different dosages of two catalysts, and different ratios of two prepolymers on the surface drying time and curing speed of sealant at low temperature were discussed. The research results showed that, ⑴ Plasticizers with different relative molecular weights had an impact on the curing rate of single-component polyurethane sealant, with smaller relative molecular weights resulting in faster curing rates. Considering the migration of plasticizers, a relative molecular weight between 270 and 350 was relatively suitable. ⑵ The higher the primary hydroxyl content of polyether polyols, the greater the improvement in surface drying time and curing speed of single-component polyurethane sealant at low temperature. Considering the influence of primary hydroxyl groups on resin compatibility, the polyether polyol with a primary hydroxyl content of 20% was relatively optimal. ⑶ When 0.15% of 2,2'-dimorpholinyldiethyl ether (DMDEE) and 0.05% of dibutyltin dilaurate (DBTDL) were added, the surface drying time at low temperature was relatively fast and the curing speed was also the fastest. ⑷ The combination of prepolymers prepared by using 4,4'-diphenylmethane diisocyanate (MDI) and those prepared by using toluene diisocyanate (TDI) could improve the surface drying time and curing speed of the sealant. When the addition amounts of the two were 25% and 10% respectively, it ensured fast surface drying time at low temperature without reducing the curing speed. 

【Keywords】polyurethane; sealant; fast surface drying; low temperature

Study on low-temperature storage properties of epoxy adhesive

An Donglan, Li Yongliang, Di Anle, Ma Li, He Hua, Huang Tao

(AVIC Xi’an Flight Automatic Control Research Institute, Xi’an 710065, Shaanxi, China)

【Abstract】Epoxy resin and curing agent begin the curing reaction generally after mixing, thus resulting in problems such as short storage life and storage difficulties. It is necessary to establish a rapid and reliable low-temperature storage performance evaluation method for all epoxy curing systems, enabling rapid verification while reducing testing costs under the premise of reliable results. In this study, two different epoxy curing systems were taken as the research object, and the viscosity was characterized at different temperatures. According to Arrhenius equation fitting, the relationship between gel time and storage temperature was derived. Finally, the reasonable storage temperature was designed based on the storage requirements. The research results showed that,⑴ The results of viscosity and gel time tests showed that at the storage temperature of -80 ℃, the properties of m-phenyldimethylamine curing system and imidazole curing system after reaching the storage life were similar to those of the new formulation, and were better than those of the original adhesive at the storage temperature of -20 ℃ after reaching the storage life. ⑵ The shear strength test results showed that the shear strength of the adhesive at the storage temperature of -80 ℃ under both curing systems met the requirements after reaching the storage life, also higher than that of the adhesive at the storage temperature of -20 ℃, and was basically consistent with the performance of the newly formulated adhesive. ⑶ Under the curing system of m-phenyldimethylamine, the shear strength of adhesive stored at -20 ℃ was slightly lower than the required index, which posed a risk of use. Under the curing system of imidazole, the shear strength of adhesive stored at -20 ℃ met the specified requirements.

【Keywords】epoxy adhesive; low temperature; storage life; gel time

Study on the performance of high-temperature resistant RTV-1 silicone sealant

Meng Jiahua¹, Chen Bingyao², Lin Zhipeng¹, Guo Shichuan¹, Dong Ying¹

(1. Guangdong SANVO Holdings Co., Ltd., Zhongshan 528400, Guangdong, China;2. Zhongshan Minhe Chemical Technology Co., Ltd., Zhongshan  528400, Guangdong, China)

【Abstract】Using α,ω-hydroxydimethylsiloxane (107 silicone rubber) as the main raw material in this study, adding fillers such as silicon micro powder, nano calcium carbonate and fumed silica, and adding crosslinking agents, silane coupling agents, catalysts, and heat-resistant additives, high-temperature resistant single-component silicone sealant cured at room temperature was then prepared. The effects of different viscosity ratios and contents of 107 silicone rubber in the formula, different ratios of fillers, and types of heat-resistant additives on the bonding properties and heat-resistance properties of silicone sealant were explored. The research results showed that,⑴ In the study on the influence of different viscosity ratios of 107 silicone rubber on the performance of silicone sealant, it was found that when the mass fraction of high viscosity 107 silicone rubber was relatively high, the elongation at break of the silicone sealant produced was also high, but its tensile strength and hardness were low, and the surface drying time was slow. ⑵ When adding 107 silicone rubber with a viscosity of 80 000 mPa·s and 107 silicone rubber with a viscosity of 20 000 mPa·s in equal proportions, and the total amount added was 50 parts, the tensile strength at room temperature was 2.51 MPa, the elongation at break could reach 407%, and also its high temperature resistance was excellent. ⑶ Different ratios of calcium carbonate and silicon micro powder had a significant impact on the bonding properties and temperature resistance of silicone sealant. As the proportion of calcium carbonate increased, the bonding strength of silicone sealant to the substrate gradually increased, but the magnitude of the increase in force gradually decreased. Compared to metal substrates, silicone sealant had stronger adhesion to plastic substrates. Calcium carbonate and silicon micro powder were commonly used as fillers for silicone sealant. Compared with calcium carbonate, silicon micro powder could improve the temperature resistance of silicone sealant to a certain extent. ⑷ The metal oxides in heat-resistance additives could improve the heat resistance of silicone sealant to varying degrees.

【Keywords】silicone sealant; high-temperature resistance; 107 silicone rubber; silicon micro powder; heat-resistance additive

Synthesis of fluorinated polyurethane prepolymer

An Jingyi¹, Zhang Tianfu²,Zhang Xiaoa¹, Wang Chengzhong¹, Jiang Shengling¹, Zhang Junying¹

(1. Key Laboratory of Carbon Fiber and Functional Polymers of Ministry of Education, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China;2. Science and Technology on Aerospace Chemical Power Laboratory, Hubei Institute of Aerospace Chemotechnology, Xiangyang  441003, Hubei, China)

【Abstract】In order to solve the problem of poor compatibility in simple blending of conventionally fluorinated polyether or polyester compounds, using azide polyether diol and fluorinated polyether diol as starting materials, based on the activity differences of isocyanate groups in isophorone diisocyanate (IPDI), a series of fluorinated polyurethane prepolymers were designed and synthesized through a stepwise pre-polymerization method. The effects of the addition method, catalyst type, reaction temperature, and reaction time of azide polyether diols on the first-step of prepolymerization reaction, as well as the effects of reaction time on the second-step of prepolymerization reaction were studied. The research results showed that, the optimal conditions for the prepolymerization reaction were to introduce azide polyether diol dropwise into the reaction system, reacted for 1 hour under the catalysis of dibutyltin dilaurate at 25 ℃, and then introduced fluorinated polyether diol (PEG-45) and reacted for 4 hours at 80 ℃. The fluorinated polyurethane prepolymer was successfully synthesized in the reaction.

【Keywords】fluorinated polyurethane; prepolymer; activity differences of isocyanate groups

Preparation and characterization of three-dimensional urchin-like TiO₂ micro-nano materials by hydrothermal method

Liu Mi¹, Lai Xian²

(1. Guangzhou Vocational and Technical University of Science and Technology, Guangzhou 510550, Guangdong, China; 2. Shaanxi University of Science and Technology, Xi'an  710021, Shaanxi, China)

【Abstract】Titanium dioxide (TiO₂) micro-nano materials with special morphology and structure have become a focus of attention and research hotspots in recent years, while how to precisely control the morphology of TiO₂ through hydrothermal method remains a major challenge. By employing a one-step hydrothermal method, using titanium tetraisopropoxide (TTIP) as an efficient titanium source, and ingeniously introducing concentrated hydrochloric acid and polyvinylpyrrolidone (PVP) as morphology-regulating agents, urchin-like TiO₂ micro-nano materials were prepared in the environment of green solvent of ethylene glycol. The effects of different reaction conditions on the structure and properties of TiO₂were investigated, and its growth mechanism was analyzed. The research results showed that the hydrothermal method could successfully prepare three-dimensional urchin-like TiO₂ micro-nano materials, and the reaction conditions had significant impacts on the materials' morphology and performance. Furthermore, under optimized conditions, when the concentration of PVP was set at 6 mg/mL, the operating temperature was controlled at 150 ℃, and the reaction time was maintained for 24 h, the dispersion performance of the sample reached the optimal state, and the integrity of its surface morphology was significantly improved.

【Keywords】hydrothermal method; urchin-like TiO₂; micro-nano materials; preparation; characterization