The application of reed-vibration mechanical spectroscopy for liquids to detect chemical reactions of an acrylic structural adhesive

There remain a number of unsolved problems about chemical reactions, and it is significant to explore new detection methods because they always offer some unique information about reactions from new points of view. For the first time, the solidification course of a modified two-component acrylic structural adhesive is measured by using reed-vibration mechanical spectroscopy for liquids （RMS-L） in this work, and results show that there are four sequential processes of mechanical spectra with time. The in-depth analyses indicate that RMS-L can detect in real-time the generation and disappearance of active free radicals, as well as the chemical cross-link processes in the adhesive. This kind of real-time detection will undoubtedly facilitate the study of the chemical reaction dynamics controlled by free radicals.

Effect of Phyllanthus emblica Linn.on Candida adhesion to oral epithelium and denture acrylic

Objective:To investigate the effect of Phyllanthus emblica(P.emblica) Linn,ethanolic extract on the adhesion of Candida albicans(C.albicans) to human buccal epithelial cells(BECs) and denture acrylic surfaces.Methods:Human BECs and transparent acrylic strips were pretreated with ethanolic extract solution of P.emblica fruits at concentration ranged from 18.7 to 300 mg/mL.After washing BECs and the strips were inoculated with three strains of C.albicans (ATCC 10281 and two clinical isolates)(10~7 cells/mL).Normal saline solution(NSS) and 0.2% chlorhexidine gluconate were used as negative and positive controls,respectively.BECs were harvested on 12μm-polycarbonate filters(Millipore,USA).The membrane filters and the strips were stained with Gram stain.Adherent yeast cells on 100 randomly selected epithelial cells and 20 randomly selected fields on each strip were counted under microscope.The statistical significance was calculated by Kruskal-Wallis and Tukey tests at a significant level of P【0.05. Results:Significant lower numbers of all strains of yeasts adhering to BECs and acrylic strips were observed after exposure to 75-300 mg/mL of plant extract compared with NSS.Conclusions: The present study demonstrates that P.emblica ethanolic extract interferes with the adhesion of C. albicans to BECs and denture acrylic surfaces in vitro.

Effect of Structural Units on the Adhesion of Acrylic Copolymers to Fibers for Warp Sizing

Radical copolymerization of acrylic acid(AA)with acrylamide(AM)or acrylamide/acrylonitrile(AM/AN)was initiated with ammonium persulfate as initiator to produce acrylic copolymers such as bicopolymer poly(AM-co-AA)and tercopolymer poly(AM-co-AN-co-AA)for revealing the effects of the structural units of the copolymers on the adhesion of the copolymers to polyester or cotton fibers for warp sizing.The adhesion was evaluated in terms of tensile strength and work-to-break of a roving impregnated with the copolymer solution.It was found that the adhesion strongly depended on type and amount of the units incorporated into the copolymeric chains.Whether the fiber is cotton or polyester,the adhesion of the bicopolymer poly(AM-co-AA)is greater than that of polyacrylic acid or polyacyamide.Excessively increasing the amount of AM or AA unit in poly(AM-co-AA)lowers the adhesion.To enhance the adhesion of the bicopolymer,a favorable mole ratio of AM to AA is 70/30.Based on this mole ratio,incorporation of acrylonitrile units into poly(AM-co-AA)to form tercopolymer enhances the adhesion.

SEED SEMICONTINUOUS EMULSION MULTI-COPOLYMERIZATION OF (METH) ACRYLATES WITH HIGH-SOLID CONTENT: EFFECT OF THE OPERATION CONDITIONS

The seeded semicontinuous emulsion multi-copolymerization of butyl acrylate (BA), 2-ethylhexyl acrylate (2EHA), methyl methacrylate (MMA), 2-hydroxyl propyl acrylate (HOPA) and acrylic acid (AA) was used to prepare the acrylic latexes with high-solid content. The effects of monomer emulsion feed rates (R(a)) and (R/E)(E) values, the ratio of emulsifier amount between the initial charge (R) and the addition monomer emulsion (E), on the polymerization reaction features, the viscosities, surface tensions,particle sizes and particle sizes distributions of latexes, T-g and the insoluble fractions of films, the 180 degrees peel strength, tack and holding power of pressure-sensitive adhesive (PSA) tapes, prepared from the latexes, were studied. Experimental study shows that the grafting and crosslinking fraction in the PSA tapes must be controlled within a suitable range to keep the balance of the 180 degrees peel strength, tack and holding power.

A New Liposomal-Drug-in-Adhesive Patch for Transdermal Delivery of Sodium Diclofenac

Liposomes are known to have considerable potential as drug carriers such as liposomal suspension, freeze dried and cream-based systems among many other liposomal formulations. In this study a new drug-in-adhesive patch was fabricated using liposome-based nanocarrier. Transfersomes as ultra-deformable liposomes are based on phosphatidylcholin 95% (phospholipon 90G) and phosphatidylcholin 50% (phosal 50PG) were prepared and further optimized in a final acrylic patch system for effective adhesion. The prepared liposomes were added to an acrylic adhesive to obtain a new hybrid transdermal patch termed as “lipo-drug-in-adhesive” patch system. The sodium diclofenac was selected as a model drug and the permeation of the drug across rat skin was evaluated (P > 0.05), using the lipo-drug-in-adhesive patch system with various percentages of transfersomes (4% - 8%w/w) and constant concentration of the drug (2% w/w). The peel strength and tack value of samples were also examined and quantified. The maximum flux of sodium diclofenac was observed in samples containing 8% (w/w) phosphatidylcholin 50%. The peel strength and tack value in samples containing phosphatidylcholin 50% were lower than those samples containing phosphatidylcholin 95%. It was observed that with increased amount of liposome in drug-in-adhesive patch system, the rate of skin permeation of the drug was also increased. It can be concluded that the developed lipo-drug-in-adhesive patch system enhances the drug release potential of transdermal delivering systems.

Synthesis and Performances of Poly(2-ethylhexyl acrylate-co-acrylic acid) Used for Warp Sizing

A series of poly （ 2-ethylhexyl acrylate-co-acrylic acid ） s （ P （2-EHA-co-AA） ）s with different mole contents of 2-ethylhexyl acrylate （ 2-EHA ） were synthesized through free radical copolymerization in ethanol for investigating the influences of copolymer composition upon the performance such as apparent viscosity, film behaviors, and adhesion to fibers for warp sizing. The content of 2-EHA was varied from 80 % to 40 %. The adhesion was estimated by measuring tensile strength and work-to-break of impregnated roving. The film behaviors were evaluated in terms of breaking strength, breaking elongation, work-to-break, and flex- fatigue resistance. It was observed that the viscosity, adhesion, and film behaviors of the copolymers strongly depended on the content of 2-EHA. Excessively increasing or decreasing the content of 2-EHA units incorporated into the copolymeric chains reduces the serviceability of P（2-EHA-co-AA） in warp sizing. The adhesion and film behaviors of the copolymcr reach their maximal values at mole content of 50 % simultaneously. Therefore, the copolymer used as sizing agent should be synthesized under equal mole of 2-EHA and AA in monomer formulation.

Efficacy and Safety of the Skin Adhesive EpinexusTM in Surgical Patients

This single-center, randomized, and controlled intervention study compared an acrylate skin adhesive, EpinexusTM (Mitsui Chemicals, Inc., Tokyo) with Dermabond AdvancedR (Ethicon, Inc., Somerville, New Jersey). The primary endpoint was cosmetic outcome at 52 weeks after treatment (Manchester Scar Scale), and the secondary endpoints were cosmetic outcome at 4 and 26 weeks after treatment (Manchester Scar Scale), wound closure, and usability. We evaluated 59 patients (29 cases and 30 controls). Failures and adverse events were also evaluated, and 8 adverse events (5 cases and 3 controls) were reported (epidermolysis, n = 4;contact dermatitis, n = 1;eczema, n = 1;and surgical wound dehiscence, n = 2). No difference was observed between groups in cosmetic outcome at 52 and 24 weeks;however, at 4 weeks, cases showed better cosmetic outcome compared with controls. With regard to usability, the treatment duration and application time were significantly longer with EpinexusTM, and ease of application was significantly better with Dermabond AdvancedR.

FPC用改性丙烯酸酯胶粘剂的固化研究

改性丙烯酸酯类胶粘剂应用于挠性印制电路板(FPC)及其基材时,其固化程度对性能有着决定性的影响。本文以自制的环氧树脂改性的丙烯酸酯类胶粘剂为例,通过动态差示扫描量热仪(DSC)从理论上分析其非等温固化的动力学行为,以研究其在室温时的储存稳定性和高温固化的工艺条件。然后通过傅里叶变换红外光谱仪(FT-IR)研究其在室温以及125~300℃温度范围内的固化反应历程,以保证该胶粘剂应用于FPC的热固性胶膜/片的固化性能或效果。研究结果表明:(1)通过非等温DSC测试,确定了改性丙烯酸酯胶粘剂的固化动力学方程,由此推算其在10~50℃的常规储存温度下的反应速率常数K值低至10^(-5) min^(-1)级别及以下,具有优异的B阶稳定性;同时在180℃及以上的K值达到10^(-1) min^(-1)级别,可以满足其高温烘烤迅速固化的使用要求。(2)由动态DSC测试得到的三种特征温度,进而推算本胶膜的理论固化温度为182℃,且在此温度下实现100%固化需时约100 min,并通过DSC测试进行了验证。(3)通过FT-IR对比验证了以上高温固化的反应历程,其在200℃处理后环氧基基本反应完全,这与以上分析的结果一致。

丙烯酸酯胶黏剂的刺激性及其防护

研究了第二代丙烯酸酯胶黏剂(SGA)对皮肤的刺激性,特别关注了其与变态反应性皮肤病的关系。实验探讨了不同材质手套对SGA的阻隔效果,发现一次性天然橡胶手套在接触胶黏剂后易发生溶胀,而加套一层一次性PE手套则能有效阻止胶黏剂的渗透和致敏成分透过。

水利工程用环氧树脂改性聚氨酯丙烯酸酯性能研究

水利工程金属结构和水工建筑物常遭受腐蚀、高速含沙水流磨蚀破坏,需对其进行便捷有效的防护。利用环氧树脂对聚氨酯丙烯酸酯(PUA)进行改性提高PUA与基体黏结性能,采用紫外光(UV)固化技术制备PUA涂层。研究了环氧树脂改性PUA的化学结构及环氧树脂用量对PUA的力学性能、热稳定性能、耐溶剂性能和抗冲磨性能的影响。结果表明,环氧树脂改性PUA的拉伸强度随着环氧树脂用量增加,呈下降趋势,当加入5%时,PUA拉伸强度为103.0 MPa,材料呈强而脆的特性。环氧树脂加入提升了PUA的拉伸剪切强度,由0.25 MPa增至1.60 MPa。同时,环氧树脂改性PUA具有良好的耐水性能、耐溶剂性能、抗冲磨性能,5%环氧树脂改性PUA抗冲磨强度为800 h/(kg·m^(2))。

3M^(TM) Acrylic Foam Tape 5363在轨道车辆按钮开关上的脱胶分析及工艺优化

随着中国轨道交通的发展,越来越多的轨交产品走出国门、走向世界,其中以地铁门系统最具特点。按钮开关作为门系统上的关键电子产品之一,有控制开、关门的作用,在国外被广泛采用到门系统上。其中设有盲文的按钮开关,因充分考虑特殊人群出行,深受国外客户的青睐。按钮开关盲文盖板粘接的可靠性就显得至关重要,要考虑列车不同的运行环境及各种外界因素,否则就会因为粘接不好,导致盲文盖板翘边或者脱落,引起客户的投诉和不满。企业不得不进行国外整改返修,耗费巨大的人力物力成本,也为公司带来巨大的质量损失。针对盲文盖板出现的粘接问题,对工艺路线进行总结优化,从源头上解决问题。

耐高温丙烯酸酯压敏胶研究进展

由于丙烯酸酯压敏胶耐高温性能不足而在诸多应用领域受到限制,近年来行业中涌现了诸多通过改性提升其耐温性的研究。本文对近年来有关丙烯酸酯压敏胶耐高温改性的研究工作进行了综述,对耐高温性能的测试方法进行了汇总和比较,对交联剂及交联方式研究、有机硅改性、丙烯酰胺化合物改性、含氟化合物改性、杂环类耐热单体改性等多种改性方法进行了分析和总结。最后,对耐高温丙烯酸酯压敏胶的发展方向进行了展望。

适用篮球修补的丙烯酸酯胶粘剂改性研究

为提高胶粘剂材料的环保性和粘接性能,试验以采用种子乳液聚合法,采用制备复配乳化剂体系制备丙烯酸酯胶粘剂,添加小分子量丙烯酸酯乳液进行共混,制备改性丙烯酸酯胶粘剂,并对其配方进行优化。结果表明,适宜过硫酸铵(APS)引发剂掺量为0.45%、种子乳液掺量为8%、乳化剂掺量为0.9%、小分子量丙烯酸酯乳液占比为20%。在优化配方下,制备的丙烯酸酯胶粘剂持粘力为43 h,180°剥离强度为7.82 N/(25 mm),具备良好内聚力和粘接性能,符合高性能丙烯酸酯胶粘剂的标准要求。

EFFECT OF ARTIFICIAL WEATHERING AND TEMPERATURE CYCLING ON THE ADHESION STRENGTH OF WATERBORNE ACRYLATE COATING SYSTEMS USED FOR WOODEN WINDOWS

The adhesion of coatings to wood is important for their long-term performance.In this study,the adhesion strength of water-based acrylate coatings used for wooden windows after exposure to artificial weathering(AW)and temperature cycling(TC)was investigated.The analysis of the adhesion quality of coatings was performed via a pull-off test and failure characteristics.The 3-layered and 4-layered white and brown acrylate dispersions from six different producers were compared and the effect of coating thickness on adhesion strength was investigated.The adhesion strength values proved to be very variable.After AW,the adhesion strength and its variability increased for all the samples.TC had no statistically significant effect on the adhesion strength values.White coating systems were initially characterized by lower adhesion strength,but after AW and TC,they reached higher adhesion strength values than brown ones.The overall highest adhesion after AW and TC was recorded for the coatings based on alkyd-acrylate hybrid basis(Producer 3),while the lowest adhesion variability after AW was measured for one type of tested acrylate coating(Producer 4).The effect of different layering on adhesion strength was not demonstrated in this study.

超支化聚氨酯丙烯酸酯胶粘剂的制备与性能

使用异佛尔酮二异氰酸酯、聚四氢呋喃二醇、三羟甲基丙烷、甲基丙烯酸羟乙酯等为原料,制备了超支化聚氨酯丙烯酸酯(HPUA)。通过加入光引发剂、活性稀释剂配制了一系列光固化胶粘剂,并对其结果进行结构表征以及热稳定性研究。探究了光引发剂种类、HPUA与活性稀释剂三羟甲基丙烷三丙烯酸酯(TMPTA)的比例以及硅氧烷偶联剂(3-氨丙基三乙氧基硅烷)用量对光固化胶粘剂性能的影响。研究结果表明:成功制备了预期产物,所合成的HPUA具有优良的热稳定性。当选用质量分数为3%的光引发剂Irgacure1173,m(HPUA)∶m(TMPTA)=1∶1,同时添加3%含量的3-氨丙基三乙氧基硅烷,制备的光固化胶粘剂的综合性能最佳。此时胶粘剂对玻璃基材的拉伸剪切强度为2.15 MPa,断裂伸长率为49.23%,凝胶率为98.56%,体积收缩率为1.02%,邵氏硬度为D55。

长开放期EPI木材胶粘剂的制备与性能表征

通过特定的乳液聚合工艺,制备了一款苯丙乳液(SAEP2),并将其应用于木材胶粘剂。系统地考察了聚乙烯醇的聚合度和浓度、异氰酸酯固化剂用量以及钙粉用量对胶粘剂开放期及粘接强度的影响。研究结果表明:胶粘剂开放期会随着聚乙烯醇的聚合度和浓度、异氰酸酯固化剂用量、碳酸钙粉末用量的增大而缩短;当m(SAEP2)∶m(10%的BP17水溶液)∶m(钙粉)=1∶1∶1,且异氰酸酯固化剂用量为13%时,制备的SAEP2胶粘剂湿强度达标(可达5.4 MPa),而开放期长达150 min。

改性豆粕胶黏剂压制三层实木复合地板工艺优化

以豆粕为原料,加入醋酸乙烯-丙烯酸酯共聚乳液和聚合MDI交联剂制成改性豆粕胶黏剂;利用改性豆粕胶黏剂压制三层实木复合地板,探讨不同工艺参数对实木复合地板浸渍剥离性能的影响。结果表明:压制三层实木复合地板的最佳工艺为热压时间15min、热压单位压力0.7MPa、固化剂用量15%,在此条件下,三层实木复合地板浸渍剥离性能较佳,满足《实木复合地板》(GB/T 18103—2022)要求。

季铵化纳米纤维素增强预油漆纸性能

【目的】为解决预油漆纸用三聚氰胺–脲醛树脂存在甲醛释放等环保问题,开展了利用无醛水性浸渍胶黏剂和涂料制备无醛预油漆纸的应用技术研究。【方法】以季铵化纳米纤维素改性水性丙烯酸酯乳液作为浸渍胶黏剂制备预浸胶纸,并在表层辊涂水性丙烯酸酯类涂料制备预油漆纸。利用X射线光电子能谱仪(XPS)、热重分析仪和万能力学试验机分别对预油漆纸的表面化学基团和元素含量变化、热稳定性能和拉伸性能进行分析和测试。【结果】原纸经浸渍季铵化纳米纤维素增强水性丙烯酸酯乳液并涂饰油漆后制备的预油漆纸纵向抗张强度和断裂伸长率分别增加了4.2倍和3.2倍,并且可任意角度折叠,柔韧性能优异。预油漆纸甲醛释放量为0.12 mg/L,达到国内外干燥器法甲醛释放量最严等级—日本标准F星级认证中F^(☆☆☆☆)级(甲醛释放量≤0.3 mg/L)要求。XPS分析表明:与原纸相比,预油漆纸表面化学结构和元素含量发生变化,经过丙烯酸酯胶黏剂和涂料处理后表面疏水性能提高。热重分析结果显示:与原纸相比,预油漆纸的热稳定性能略微下降。除表面耐磨性能和硬度,预油漆纸饰面板的抗冲击性能、耐干热性能、耐湿热性能、耐水性能和耐污染腐蚀性能均能满足GB/T 15102—2017《浸渍胶膜纸饰面纤维板和刨花板》和GB/T 37005—2018《油漆饰面人造板》的要求。【结论】利用季铵化纳米纤维素增强的预油漆纸具有良好的环保和力学性能。

丙烯酸酯预聚物及其压敏胶的制备与性能研究

以甲基丙烯酸甲酯(MMA)、丙烯酸异辛酯(2-EHA)、丙烯酸(AA)和丙烯酸羟基乙酯(HEA)为共聚单体,以偶氮二异丁腈(AIBN)为引发剂,乙酸乙酯(EA)为溶剂,通过自由基聚合反应合成了丙烯酸酯聚合物。然后接枝丙烯酸异氰基乙酯(AOI)单体,合成了丙烯酸酯预聚物,并用于制备UV固化型压敏胶(PSA)。研究了其结构性能以及反应温度对预聚物的相对分子质量及分布的影响、低用量的功能单体AA和交联单体AOI以及重均分子量(M_(w))对PSA性能的影响。研究结果表明:(1)红外光谱分析说明,预聚物和单体几乎全部参与聚合反应。相对分子质量及分布分析表明,质均分子量(M_(n))和重均分子量(M_(w))随着反应温度的升高而降低,但分布系数(PDI)保持在3.56~3.79之间,PDI的变化和温度没有明显对应的关系。DSC分析测定T_(g)为-63.53℃,远低于其他研究报道PSA的T_(g)(-30~-50℃),可适用温度下限显著降低。(2)综合考虑,AA和AOI的用量分别为1.0%和0.16%,且预聚物的M_(w)约为45.7万时,PSA的综合性能相对最佳。不同频率下的流变性能解释了压敏性能与黏弹性的内在关系。

天然薄荷醇改性聚丙烯酸酯防细菌黏附剂的制备及其在棉织物中的应用

利用天然小分子薄荷醇(MT)的立体防细菌黏附功能,通过酯化反应将其接枝到丙烯酸酐(AC)上,继而聚合生成新型含MT防细菌黏附侧链的聚丙烯酸酯共聚物[P(MAC-co-AA)]。采用浸轧法处理棉织物,赋予棉织物优良的防细菌黏附效果。结果表明,当MT和AC物质的量比为2∶1,反应温度为70℃,反应时间为5 h时,P(MAC-co-AA)酯化率高达70.9%,对大肠杆菌和金黄色葡萄球菌的防细菌黏附效果最好。相比MT,P(MAC-co-AA)的最大分解温度由130℃提高到252℃,其热稳定性大幅提升。当P(MAC-co-AA)整理液用量为20 g/L时,P(MAC-co-AA)整理棉织物对大肠杆菌和金黄色葡萄球菌的防细菌黏附率高达99.9%。