微波合成酚醛树脂/蒙脱石纳米复合材料结构的研究

在微波加热条件下制备酚醛树脂/有机改性蒙脱石纳米复合材料,研究了蒙脱石不同加入方法、不同加入量和搅拌时间对有机改性蒙脱石分散效果的影响,并用X射线小角衍射观测其微观结构。结果表明,苯酚和甲醛可以进入蒙脱石片层间进行缩聚反应,使蒙脱石片层间距扩大甚至剥离。     

Preparation and properties of polyamide 6/polypropylene–vermiculite nanocomposite/polyamide 6 alloys

Polypropylene–vermiculite nanocomposites can be achieved by simple melt mixing of maleic anhydride‐modified vermiculite with polypropylene. Maleic anhydride acts either as a compatibilizer for the polymeric matrix or as a swelling agent for the silicate. Compatibilized blends are injection molded directly from polyamide 6 and polypropylene–vermiculite nanocomposites. Scanning electron microscopy observation reveals that a two‐phase structure consisting of polypropylene–vermiculite nanocomposite and polyamide 6 is formed in the blends. The absence of vermiculite reflections in the X‐ray powder diffraction patterns indicates that the polypropylene–vermiculite phase exhibits nanocomposite characteristics. Tensile test shows that the tensile modulus of the polymer alloy tends to increase with increasing polypropylene–vermiculite nanocomposite content. The tensile strength of composite containing 8 wt % vermiculite is higher than that of pure polyamide 6. Finally, the thermal properties of the nanocomposites are determined by dynamic mechanical analysis, differential scanning calorimetry, and thermogravimetric measurements. The effects of maleic anhydride addition on the formation of polypropylene–vermiculite nanocomposite reinforcement and on the mechanical properties of composites are discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2330–2337, 2002     

新型含磷酚醛树脂的合成与性能

通过亚膦酸酯与碳碳双键之间的亲电加成反应,合成了一种新型的含磷马来酰亚胺酚醛树脂。采用红外光谱(FTIR)和元素分析法对聚合物的结构进行了表征。并用此含磷酚醛树脂作为环氧树脂的固化剂制得了一含磷氮的环氧固化物。采用热分析法、极限氧指数法对相应环氧固化物的耐热性能和阻燃性能进行了表征。研究结果表明:以该含磷聚合物作为环氧树脂的固化剂,对稳定固化物骨架碳的结构和交联成炭能力的提高起到了增强作用;环氧固化物具有较高的玻璃化转变温度(145.4℃)和较高的热稳定性(T508℃),极限氧指数显示其具有较好的阻燃性能。     

硼改性酚醛树脂的合成与性能

利用半成品酚醛树脂粉与硼酸直接混合,然后固化得到硼含量不同的硼酚醛树脂,并用傅里叶红外光谱、热重分析和冲击试验等方法对其性能进行了分析。红外分析结果表明,硼酸与酚醛树脂中的酚羟基、苄羟基发生了反应,生成了新的交联键。热分析结果发现,在酚醛树脂中加入硼酸能提高树脂的耐热性,当硼酸加入量为10%时达到最高值。硼酚醛树脂的冲击强度先随硼酸加入量的增大而增加,在5%时达到最大值,然后下降。     

硼酚醛树脂的制备和研究进展

由于在酚醛树脂(PF)的分子结构中引入了无机硼元素,故硼酚醛树脂(BPF)具有优异的抗氧化性、高温稳定性、力学性能和高残炭率等特点,并且在热解时不会释放出有毒气体,因而已成为目前最成功的PF改性品种之一,在汽车、军事装备和航空航天等领域中应用广泛。总结了国内外近年来有关制备BPF的各种方法,简要介绍了BPF的性能及应用研究,并对该领域的研究方向作了展望。     

Preparation of organic vermiculite/polymethylmethacrylate nanocomposite featuring excellent mechanical and thermal properties via ultrasonic in situ polymerisation

To improve the dispersion of organically modified vermiculite (OVMT) in polymethylmethacrylate (PMMA), the method of ultrasonic in situ polymerization was introduced, and a series of OVMT/PMMA nanocomposites were successfully prepared. The structure, morphology, and mechanical and thermal properties of as-prepared sample had been investigated. Results showed that the assistance of ultrasonic irradiation could be beneficial for the good homogeneous dispersion and strong interfacial interaction of OVMT in PMMA. Consequently, the obtained nanocomposites showed better mechanical and thermal properties than those prepared without the assistance of ultrasonic irradiation. When the OVMT content was 3 wt.%, the nanocomposite prepared by ultrasonic in situ polymerization exhibited the Young's modulus, tensile strength, elongation at break and degradation temperatures for 5% and 50% weight loss of 1177 MPa, 65 MPa, 14%, 219.82ºC and 373.91ºC, respectively. These results suggested the great potential application of ultrasonic in situ polymerization for the synthesis of polymer/clay nanocomposite.     

HDI-BPA酚醛树脂的合成及应用性能

以双酚A(BPA)酚醛树脂和六亚甲基二异氰酸酯(HDI)为原料,在二月桂酸二丁基锡(DBTDL)催化作用下合成了HDI-BPA酚醛树脂。采用FTIR、~1HNMR、GPC、有机元素分析等对HDI-BPA酚醛树脂的化学结构和相对分子质量进行了表征,结果表明目标产物成功制备,其M_w为3376。探讨了反应温度、反应时间、物料配比、催化剂用量等因素对目标产物中异氰酸酯基质量分数及接枝率的影响。通过建立异氰酸酯基质量分数和接枝率的二次回归方程,使用响应面分析法中的Box-Behnken Design(BBD)对HDI-BPA酚醛树脂的合成工艺进行了优化,最佳工艺条件为:反应温度32℃、反应时间为55 min、m(BPA酚醛树脂)∶m(HDI)∶m(DBTDL)=0.2101∶1∶0.0025。在此条件下,合成产物中异氰酸酯基质量分数为25.51%,接枝率为48.929%。最后,在HDI-BPA酚醛树脂中加入E-51固化剂,制备出HDI-BPA酚醛树脂胶黏剂,其最大粘结力达283.69 N,相对于BPA酚醛树脂胶黏剂的性能提升了3.7倍,表明HDI的加入显著提高了BPA酚醛树脂对低极性皮革基材的粘结性能。同时,HDI-BPA酚醛树脂胶黏剂的接触角为93.5°,表现出较好的疏水和耐水性能。     

Thermal degradation and fire performance of plywood treated with expanded vermiculite

The new flame‐retardant plywood was manufactured by adding expanded vermiculite (EVMT) in the adhesive and by surface treatment as a flame‐retardant coating. The study discussed the effect of EVMT to the limited oxygen index values of samples. The thermal degradation process of plywood samples has been investigated by thermal analysis. The result showed that EVMT increased all the limited oxygen index values of the treated samples and decreased the thermal activation energy at a high degree of degradation. Scanning electron microscope (FEI, Holland, The Netherlands) images showed that EVMT could form a protective coating, which improved the flame retardancy of plywood. Copyright © 2015 John Wiley & Sons, Ltd.     

耐水性膨胀蛭石板材的研制

以膨胀蛭石、水玻璃、K2S iF6、硅丙树脂为原料,利用热压成型工艺,制备了具有耐水性好、强度高、导热系数低等优异性能的蛭石保温防火制品。研究了各组分配比以及成型时的压缩率对蛭石保温防火制品的抗压强度、吸水率、导热系数等物理性能的影响。结果表明,m(K2S iF6)/m(水玻璃)=0.022,m(水玻璃)/m(膨胀蛭石)=1.3,压缩率为74%,硅丙树脂掺量为14%,150℃、0.2 MPa时热压3 h可制备出抗压强度为4.58 MPa,导热系数为0.084 W/m.k,吸水率为5%的蛭石保温防火制品,具有可锯、可钉、可刨等机械加工性能。     

BPS-BPA酚醛环氧树脂的合成及其应用性能

以双酚A环氧树脂(BPA酚醛树脂)和4,4-二羟基二苯砜(BPS)为原料,环氧氯丙烷为桥连剂,在四丁基溴化铵(TBAB)的催化作用下合成了BPS-BPA酚醛环氧树脂(目标产物)。采用FTIR、1HNMR、GPC、EDS等对产物的化学结构及分子量进行测试。结果表明,产物Mw为4355且表现出较好的耐温性能,此外还探讨了反应温度、反应时间、物料配比、Na OH用量等因素对目标产物环氧值的影响。利用正交实验设计获得了目标产物的最佳工艺条件为:反应温度110℃,反应时间2.5 h,m(BPA酚醛树脂)∶m(BPS)=1∶0.9,Na OH用量1.98 g,在该条件下合成产物的环氧值为0.718。最后向目标产物中加入聚酰胺树脂固化剂,得到的胶粘剂具有优良的粘结性能,其最大粘结力达100.66 N,层间结合强度0.788 N/m,对低极性聚丙烯材料具有很好的附着性能。     

对苯二甲醛酚醛树脂的制备及其固化动力学研究

基于酚醛树脂原料中甲醛的危害性与不可再生性,使用安全、可再生的对苯二甲醛代替甲醛,合成了一种新型的酚醛树脂——对苯二甲醛酚醛树脂。采用核磁、红外、GPC和流变仪等分析手段对此类树脂的结构与性能进行了表征。为了进一步提高该树脂的热性能,使用二茂铁甲醛对其进行改性。采用Kissinger方程、等转换法及双参数自催化模型对改性前后树脂的固化动力学进行了研究,明确了二茂铁甲醛在树脂固化中的作用机理。最后通过MDSC和TG研究了改性前后树脂固化物的热性能,结果表明：在加入15%的二茂铁甲醛后,改性树脂呈现出优异的热性能,其玻璃化转变温度为319.3℃,起始分解温度为397.7℃,在800℃氮气气氛下质量保持率高达76.07%。     

有机硅改性酚醛环氧树脂耐高温胶粘剂的研制

采用甲基苯基硅树脂对酚醛环氧树脂进行改性,硼酚醛树脂与自制固化促进剂作为固化剂,辅以纳米蒙脱土、绢云母粉作为填料,制备出一种能在300℃条件下长期使用的耐高温胶粘剂。在不同的配方及固化工艺条件下測定了有机硅改性酚醛环氧树脂体系的剪切强度,分析了甲基苯基硅树脂／酚醛环氧树脂比例关系、硼酚醛树脂与自制固化促进剂比例关系、固化剂用量、固化工艺条件、纳米蒙脱土的加入量对体系的影响。     

酚醛树脂/NBR基蒙脱土纳米复合材料的聚集态

利用3种蒙脱土(S-MMT，TG-2，OLS）和1种短切玻璃纤维，分别与酚醛树脂(PF)／丁腈橡胶(NBR)熔融混合，制备了PF／NBR纳米复合材料，通过X射线衍射和透射电子显微镜分别对这些复合材料的聚集态进行了研究。结果表明，在所有PF／NBR／(S-MMT，TG-2，OLS)纳米复合材料中，S-MMT，TG-2，OLS的层间距均大于复合之前各自的层间距；即使是未经有机化改性的S-MMT，在与PF／NBR炼融复合过程中也使聚合物分子链插入到S-MMT的层间，但插层水平较低；其次，后固化处理有利于增大复合材料中蒙脱土硅酸盐片的层间距。     

Preparation and properties of polar polypropylene blends containing phenolic resin

It is often pointed out that low water absorption and moisture permeability are drawbacks of polypropylene (PP). In this study, blending with an amorphous polymer was used to modify PP. For improving the properties of PP without any property depression, PP was blended with phenolic resin‐Novolak type (PRN). PP/PRN blends were investigated by a contact angle test for surface properties to determine whether PP had hygroscopic characteristics due to the existence of PRN in the blends. In addition, for the sake of efficient investigation in this blend, chemical structure, mechanical measurement, thermal analysis, and morphological observations were also studied. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1029–1038, 1999     

Preparation and swelling characteristics of a superabsorbent nanocomposite based on natural guar gum and cation‐modified vermiculite

A series of novel superabsorbent nanocomposites were prepared by the solution radical polymerization of natural guar gum (GG), partially neutralized acrylic acid [sodium acrylate (NaA)], and cation‐exchanged vermiculite (Mⁿ⁺‐VMT) with ammonium persulfate as the initiator in the presence of the crosslinking agent N,N′‐methylene‐bis‐acrylamide. Fourier transform infrared analysis revealed that NaA was grafted onto the GG chains and that Mⁿ⁺‐VMT participated in the polymerization. X‐ray diffraction results showed that the occurrence of the cation‐exchange process changed the interlayer gap of vermiculite (VMT) and that Mⁿ⁺‐VMT was exfoliated during polymerization to form a nanocomposite. The exfoliated VMT led to better dispersion in the GG‐g‐poly(sodium acrylate) matrix, as shown by scanning electron microscopy and transmission electron microscopy analysis. Mⁿ⁺‐VMT improved the water absorption of the nanocomposite more remarkably than raw VMT, and Al³⁺‐VMT enhanced the water absorption to the highest degree. The nanocomposite exhibited intriguing overshooting swelling characteristics in a multivalent saline solution and acidic pH solution and showed switching pH‐responsive behaviors in buffer solutions between pH 2 and pH 7.2. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

酚醛在丙烯酸树脂防火改性中的应用

以酚醛树脂为主防火剂、胺类为协效剂,研究了其种类、用量对丙烯酸树脂防火性能的影响,采用锥形量热仪和热重分析仪对酚醛改性丙烯酸树脂的燃烧性能和热稳定性进行了测试,并对燃烧后的炭层结构进行了电镜分析。结果表明,硼酚醛树脂能显著提高丙烯酸树脂的防火性能,硅酸铝、六次甲基四胺具有有良好的协效作用;当丙烯酸树脂与硼酚醛树脂质量比为50:50,硅酸铝质量分数为7%,六次甲基四胺为2%时,改性树脂耐燃时间达到39min,点燃时间(TTI)及热释放速率峰值出现时间明显延长,热释放速率明显降低,800℃时残炭率为45%,热稳定性明显提高,燃烧烧后形成了表面为致密网状、断面为微细泡孔状的炭层结构,防火性能提高。     

水性酚醛环氧树脂乳液的制备

采用F-11型乳化剂和相反转技术制备水性酚醛环氧树脂乳液,研究了乳化剂的用量、乳化温度、乳化时间和搅拌速率对所得水性酚醛环氧树脂乳液稳定性的影响,得出了较佳的乳化工艺条件:乳化剂浓度为9.0%～10.0%、乳化温度为70℃、搅拌速度为800～1000 r/min、乳化时间为40～50 min并采用激光粒度衍射分析仪表征了所制备的水性酚醛型环氧树脂乳液的粒径在500～800 nm。     

Gelatin/montmorillonite hybrid nanocomposite. I. Preparation and properties

Gelatin/montmorillonite (MMT) hybrid nanocomposite was directly prepared with unmodified MMT and gelatin aqueous solution. Thermal and mechanical properties of the composite were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and tensile tests. The results indicated that an intercalated or partially exfoliated nanocomposite could be achieved, and the properties of the composite were significantly improved. A T_g peak of high temperature disappeared in the DSC curve of the composite, and the thermogravity and thermally decomposed rate decreased obviously. The tensile strength and Young's modulus were also improved notably, which varied with MMT content, as well as the pH of gelatin matrix. Meanwhile, SEM photographs showed a plasticizing trend of gelatin fracture surface due to intercalation with MMT. Furthermore, the wet mechanical behavior was initially studied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1189–1194, 2002     

剥离型酚醛树脂/蒙脱土纳米复合材料研究

用十六烷基三甲基溴化铵(CTAB)对蒙脱土进行了有机化处理,使蒙脱土由亲水性变成亲油性。采用XRD、FTIR及TEM研究了有机蒙脱土及其在酚醛树脂中的剥离行为,制备了酚醛树脂/蒙脱土纳米复合材料并测试了其层间剪切性能和烧蚀性能。实验结果表明,经CTAB处理的蒙脱土与酚醛树脂具有良好的相容性,且CTAB的含量较多时所制得的有机蒙脱土的结构较好,根据Bragg方程计算,CTAB用量超过蒙脱土量50%时,蒙脱土的片层间距由原来的1.48 nm增加到2.33 nm;有机蒙脱土用量小于5%时生成完全剥离型酚醛树脂/蒙脱土纳米复合材料;与碳布增强酚醛树脂复合材料相比,碳布增强酚醛树脂/蒙脱土纳米复合材料的力学性能和烧蚀性能均有一定的提高和改善,层间剪切强度随蒙脱土含量的增多而增大,蒙脱土用量为15%时,层间剪切强度提高了27.1%,线烧蚀率在用量为3%时降低了48.5%,质量烧蚀率变化不明显。     

磺化酚醛吸水树脂的研制

通过引入水化基团—CH2SO3-、控制合成反应工艺、增韧改性等措施,以亚硫酸氢钠、甲醛和苯酚为原料,以ZR-1为增韧改性剂,首次成功研制了磺化酚醛吸水树脂SPA。考察确定了优化反应条件：甲醛与苯酚的摩尔比为1.5～1.8,以无水亚硫酸钠为催化剂,通过磺甲基化法引入磺酸基,磺化度控制在20%,用1%的ZR-1进行增韧改性。制得的SPA为暗红色,具有粘弹性的块状树脂,强度达2 MPa以上,拉伸伸长率为194%,吸水7 h达到饱和,吸水倍数3.2倍。