国外线形酚醛树脂研究进展

综述了国外研究人员通过理论数学模型模拟线形酚醛树脂的固化行为,运用红外光谱、核磁共振、差示扫描量热、热失重、扫描电子显微镜等不同的研究手段验证了影响固化行为的因素。总结了线形酚醛树脂的改性研究现状,通过加入聚酰胺、甲阶酚醛增容剂来增韧线形酚醛树脂;通过重氮偶合或酯化反应生成阻燃基团,提高了线形酚醛树脂的阻燃性能;通过原位互穿网络法使线形酚醛树脂耐热性和力学性能提高;与无机纳米粒子和片层共混可以提高线形酚醛树脂玻璃化转变温度和热稳定性;结合了线形酚醛树脂和环氧树脂各自优点的环氧酚醛树脂,经改性后性能得到进一步提高。     

硼-腰果酚改性酚醛树脂的制备及固化动力学

针对酚醛树脂(PF)耐热性和韧性不足的缺点,采用硼、腰果酚对酚醛树脂进行改性,考察了硼酸用量和腰果酚用量等对改性酚醛树脂性能的影响。红外(FT-IR)分析结果表明,硼酸与酚醛树脂中的酚羟基发生了反应,生成了新的交联键。通过热重(TG)分析,结果表明经硼改性的酚醛树脂耐热性能明显提高。通过非等温差示扫描量热法(DSC)分析了改性酚醛树脂在不同升温速率下的固化行为,采用Ozawa法和Crane方程建立了改性酚醛树脂的固化动力学模型,确定了其固化工艺参数。     

磷改性酚醛树脂的制备与性能

通过DOPO(9,10–二氢–9–氧杂–10–磷杂菲–10–氧化物)和多聚甲醛反应制备了含磷单体ODOPM(9,10–二氢–9–氧杂–10–磷杂菲–10–羟甲基–10–氧化物),并用于制备磷改性酚醛树脂。通过差示扫描量热(DSC)仪测试体系DOPO的反应程度,通过红外光谱表征ODOPM的结构,通过热重分析测试改性酚醛树脂体系的热行为,通过极限氧指数和垂直燃烧法测试树脂体系的阻燃性能,通过扫描电子显微镜观察树脂燃烧后残炭的微观形貌,并采用万能试验机测试树脂样条的强度性能。实验结果表明:实验成果制备得到目标产品ODOPM,随着含磷单体ODOPM含量的提高,酚醛树脂的阻燃性能随着提高,酚醛树脂的残炭量也随着提高。酚醛树脂通过凝聚相阻燃机理起到阻燃作用。当磷改性酚醛树脂的ODOPM单体含量为15%时,树脂的LOI值可以达到32.4%,并通过V–0垂直燃烧测试,并且磷改性酚醛树脂保持较好的强度。     

钨酚醛树脂固化反应动力学研究

以六亚甲基四胺为钨酚醛树脂的固化剂,采用差示扫描量热法(DSC)研究了该体系的固化过程,得到了钨酚醛树脂固化反应的表现动力学参数,它对树脂的固化工艺选择具有重要意义。     

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。     

热塑性木质素酚醛树脂固化动力学研究

采用差示扫描量热法对热塑性木质素酚醛树脂（LDP）在２５～２５０℃范围内,以５、１０、１５、２０℃／min升温速率进行了动态固化反应研究。研究表明,随着升温速率的提高,树脂的起始固化温度Ti、峰顶温度Tp以及终了固化温度Tf均有提高,LDF的固化过程可以通过改变固化剂用量来优化固化行为,当固化剂用量达到１２％（质量分数,下同）时其固化曲线与普通酚醛树脂固化曲线接近,且犜狆大幅降低（与普通酚醛树脂比较）。固化反应热随升温速率和固化剂用量的改变变化不明显。采用Ozawa方程对DSC数据进行动力学研究,得到LDF固化反应活化能为８５．６４KJ/mol     

碳基复合材料用耐高温胶黏剂的研制

采用耐热酚醛树脂杂化了磷酸盐胶黏剂,以纳米氧化铝、氧化锆和氧化锌为固化剂,制备了一种对C/C和C/SiC复合材料具有良好粘接性能的胶黏剂。通过不同测试温度下的剪切强度,差示扫描量热仪（DSC）,热失重（TG）以及扫描电子显微镜（SEM）探究了杂化胶黏剂的力学性能、固化行为、耐热性能以及高温下胶黏剂结构的变化。结果表明：酚醛树脂的加入,保持了耐热性能,降低了体系固化的固化温度,有效地提高了磷酸盐胶黏剂对C/C、C/SiC两种复合材料力学性能,室温下剪切强度均高于10MPa。     

木质素酚醛树脂的固化动力学及机理研究

通过差示扫描量热法（Dsc）和红外光谱（IR）分别研究了木质素酚醛树脂（LPF）的固化动力学及机理。DSC分析表明,LPF的固化反应起始温度比酚醛树脂高,终止温度及活化能比酚醛树脂低,因此,LPF凝胶点比酚醛树脂高,贮存稳定性比酚醛树脂好,固化速度比酚醛树脂快;IR分析表明,LPF的固化机理与酚醛树脂相似,都是羟基之间及羟基与芳环上的氢之间的缩合反应。不同的是LPF固化后仍有部分醚键结构。     

无卤阻燃PF/EP/GF布复合材料的固化性能和阻燃性能

采用环氧树脂(EP)作固化剂,2,4,6-三(二甲胺基甲基)-苯酚(DMP30)作固化促进剂改善酚醛树脂(PF)的固化性能,以氢氧化铝和有机磷阻燃剂协同改性其阻燃性能,将其涂覆于玻璃纤维(GF)布上,压制成无卤阻燃PF/EP/GF布复合材料.用傅立叶变换红外光谱(FTIR)仪和差示扫描量热(DSC)仪对无卤阻燃PF/EP/GF布复合材料的固化反应机理、固化反应动力学进行了分析研究,并测试了该复合材料的阻燃性能.结果表明,无卤阻燃PF/EP/GF布复合材料的固化反应表观活化能Ea=75.7 kJ/mol、反应级数n=0.91,起始固化温度、固化峰顶温度、固化终止温度分别为108.6、133.2、152.9℃;当氢氧化铝质量分数为14%、DMP30质量分数为1%、有机磷阻燃剂质量分数为4.8%时,无卤阻燃PF/EP/GF布复合材料的固化性能、阻燃性能均达到较佳状态.     

不同固化体系对环氧粉末涂料性能的影响

通过非等温示差扫描量热分析(DSC),热重分析(TGA)及物理力学性能测试研究了分别以双氰胺、二氨基二苯基砜、线形酚醛树脂为固化剂,2-甲基咪唑为固化促进剂的环氧树脂体系的固化行为,热稳定性及其粉末涂料性能,并利用外推法求出不同固化体系的理论固化温度。结果表明:双氰胺/2-甲基咪唑体系的综合性能最好,其理论固化温度为142℃,热失重起始分解温度为410℃,冲击强度为50 cm,60°光泽为83,表面电阻为1.33×1012Ω。     

Addition‐cure phenolic resins based on propargyl ether functional novolacs: synthesis,curing and properties

Thermosetting phenolic resins, bearing varying extents of propargyl ether groups (PN resins), have been synthesized by the Williamson reaction of a novolac with propargyl bromide and the products characterized. The resin precursors were cured through Claisen rearrangement of the propargyl ether groups and thermal polymerization. The activation energy for thermal cure is substantially lower than that of model bispropargyl ether compounds but is quite independent of the degree of functionalization. The isothermal cure profile, extrapolated from non‐isothermal DSC kinetics studies is consistent with the results from DMA studies. The mechanical properties of glass composites of the resins, of varying propargyl contents, reveal good consolidation of the interphases, evident from the initial gain in both interlaminar shear strength (ILSS) and flexural strength. The benefits of better resin–reinforcement interactions are not retained on crosslinking the resin further, wherein the composite fails by a combination of fibre debonding and brittle fracture of the matrix. Although the resins show better thermal stability than cured resoles, a higher extent of propargylation is detrimental for the thermal stability. Resins with moderate propargylation show good mechanical and thermal properties. © 2001 Society of Chemical Industry     

富含中孔的活性炭制备及其电化学性能研究

以线型酚醛树脂为前驱体,Ce(NO3)3为催化剂,通过水蒸气活化法,制备了中孔率高达82%的酚醛树脂基活性炭。N2吸附和扫描电镜的结果表明,Ce(NO3)3对水蒸气活化具有明显的催化作用。电化学性能测试的结果表明,这种富含中孔的活性炭具有较好的电化学性能,其比电容达140F/g,而且在高电流密度下,具有较好的比电容保持率,适合大电流充放电。     

一种含磷酚醛/环氧树脂阻燃性的研究

以双酚S、甲醛和三聚氰胺为原料合成含氮线性酚醛树脂,并用其作为固化剂,结合阻燃剂甲基膦酸酐对环氧树脂进行阻燃改性。利用TGA对环氧/酚醛树脂与环氧/酚醛树脂/膦酸酐两种浇铸体系的热稳定性能进行了比较研究。结果表明甲基膦酸酐为阻燃剂,酚醛树脂固化环氧树脂能得到效果较好的阻燃材料,垂直燃烧试验结果为UL-94V-0级。     

酚醛树脂砂在油井固砂中的应用研究

分别合成了热塑性和热固性酚醛树脂,将2者混合后加入固化剂并与砂混合得到酚醛树脂覆膜砂并测试了其拉伸强度、弯曲强度,渗透性和热老化性能。结果表明,当酚醛树脂质量占砂子总质量的3%时,覆膜砂力学强度和渗透性满足再造井壁要求。采用热固性酚醛树脂与六次亚甲基四胺协同固化热塑性酚醛树脂,产品强度高,储存稳定性好。     

纳米SiO_2对酚醛环氧树脂改性研究

以双酚A及甲醛为基本原料,加入纳米SiO2制备了纳米氧化硅改性酚醛树脂预聚体,其与环氧树脂继续共聚得到纳米氧化硅改性酚醛环氧树脂。通过红外光谱、粒径分布仪、X射线衍射、扫描电镜分析及涂膜性能测试对产物进行了研究和表征。结果表明,纳米氧化硅均匀分布在共聚物中,说明纳米氧化硅中的羟基参与了酚醛的共聚;纳米SiO2的加入对酚醛环氧树脂的结构无太大影响。与未改性醛醛环氧树脂比较,纳米SiO2的加入可有效提高涂层的耐水煮、黄变、硬度、吸水率及耐盐水腐蚀性。     

高残炭酚醛树脂的研究进展

综述了高残炭酚醛树脂:硼改性、钼改性、芳基酚改性及硅氮烷改性酚醛树脂,酚三嗪树脂,苯并恶嗪树脂的研究进展。上述改性后的酚醛树脂,耐热性显著提高。这些研究为耐烧蚀材料的应用提供了理论依据,为新一代的高残炭树脂的开发提供了方向。最后指出酚醛树脂在今后的耐烧蚀材料领域仍然会发挥重要的作用。     

Preparation and properties of phosphorus‐ and silicon‐modified phenolic resin with high ablation resistance

In order to further improve the ablation resistance of common phenolic resins, a modified phenolic resin containing phosphorus and silicon (SPPR) was synthesized and the corresponding properties were evaluated. With phosphorus and silicon involved in the macromolecule, SPPR showed excellent flame retardancy and obviously enhanced value (44.8%) of the limiting oxygen index. The thermal stability and charring performance of SPPR were greatly improved, with maximum decomposition temperature of over 500 °C and carbon yield of 60.1% in nitrogen. Differential scanning calorimetry indicated that the curing temperature shifted from 157 °C for the conventional phenolic resin to 182 °C for SPPR. Moreover, an improvement of impact strength from 4.3 to 16.5 kJ m^?2 confirmed that incorporation of flexible Si? O chain had a noticeable effect on the mechanical properties of SPPR. Such a modified phenolic resin has promising application prospects serving as an ablation material with high performance. © 2019 Society of Chemical Industry     

Engineering biomass into formaldehyde‐free phenolic resin for composite materials

The use of formaldehyde to prepare phenol‐formaldehyde (PF) resins is one of the primary challenges for the world‐wide PF industry with respect to both sustainability and human health. This study reports a novel one‐pot synthesis process for phenol‐5‐hydroxymethylfurfural (PHMF) resin as a formaldehyde‐free phenolic resin using phenol and glucose, and the curing of the phenolic resin with a green curing agent organosolv lignin (OL) or Kraft lignin (KL). Evidenced by ¹³C NMR, the curing mechanism involves alkylation reaction between the hydoxyalkyl groups of lignin and the ortho‐ and para‐carbon of PHMF phenolic hydroxyl group. The curing kinetics was studied using differential scanning calorimetry and the kinetic parameters were obtained. The OL/KL cured PHMF resins were tested in terms of thermal stability, and mechanical properties for their applications in fiberglass reinforced composite materials. The results obtained demonstrated that OL/KL can be promising curing agents for the PHMF resins. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1275–1283, 2015     

三乙醇胺催化制备热固性酚醛预聚体的研究

酚醛树脂作为应用广泛的热固性树脂,其预聚体的固化温度以及固化物的分解温度对其使用范围有重要影响。使用三乙醇胺制备热固性酚醛预聚体,利用差示扫描量热分析(DSC)和热失重分析(TG)等分析手段,表征了不同三乙醇胺催化制备酚醛树脂的固化过程和热失重过程。DSC测试表明,用三乙醇胺催化合成酚醛预聚体,当催化剂用量较低时,随着催化剂用量的增加,预聚体的固化温度逐渐降低;但当催化剂用量超过19g时,预聚体的固化温度逐渐升高。TG测试表明,三乙醇胺催化制备酚醛预聚体,其固化产物的热稳定性均不理想,几乎随着温度的升高呈现线性的失重。     

Mechanical properties,thermal stability,and flame retardance of novolac‐type phenolic resin blended with poly(dimethylsiloxaneadipamide)

Mechanical properties (flexural strength, flexural modulus, and notched Izod impact strength), thermal stability, and flame retardance of poly(dimethylsiloxane adipamide) (PDMSA)‐toughened novolac type phenolic resin were investigated. Mechanical properties of modified novolac‐type phenolic resin increase with PDMSA contents, because the soft segment of PDMSA absorbs the loads in the network of brittle novolac‐type phenolic resins. TGA results show that the thermal degradation temperatures are higher than 400°C, and the temperature of 10% weight loss increases with increasing the PDMSA content. The char yield increases with novolac‐type phenolic resin content. The morphologies of the fracture surface of the modified novolac‐type phenolic resin were investigated by scanning electron microscopy (SEM). Morphological results agree with those from mechanical properties of the modified novolac‐type phenolic resin. The modified novolac‐type phenolic resin also shows excellent flame retardance that is UL‐94, V‐1, and the limited oxygen index is higher than 35. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 631–637, 2001