中文论文文摘

    本研究在催化剂和助溶剂作用下，以聚乙烯醇(PVA)为分散剂，乙二醛为交联剂，以苯乙烯(St)、丙烯酸丁酯(BA)、甲基丙烯酸(MAA)、甲基丙烯酰氧乙基三甲基氯化铵(DMC)和丙烯酸十八酯(ODA)为主要单体，采用无皂乳液聚合法制备改性阳离子丙烯酸树脂。采用多种现代分析手段对其结构、形态和热性能进行了表征。研究了w(PVA)、n(BA)/n(St)、w(DMC)、w(MAA)和w(乙二醛)对树脂乳液粒径及粒径分布和纸张的施胶度及表面强度的影响，并分析了w(PVA)、n(BA)/n(St)、交联剂、助溶剂对乳液流变性的影响。讨论了改性阳离子丙烯酸树脂胶膜力学性能和耐水性的影响因素。
    改性阳离子丙烯酸树脂可应用于造纸表面施胶和浆内施胶。本文对该树脂对纸张表面施胶和浆内施胶的实际应用效果及其过程作用机理进行了初步探讨。
研究结果表明：
    (1)较佳的无皂乳液聚合工艺：半连续种子聚合法，w (DMC)=10%，w(PVA)=8%，w (catalyst)=0.2%，w (MAA)=5%，n (BA)：n (St)=1.1：1，w(ODA)=0.8%，w(乙二醛)=3.5%，w(异丙醇)=0.5%；聚合反应温度为80℃，在反应初期加入1/4的单体及1/3的引发剂，反应1h，然后在1h内缓慢滴加完剩余单体及引发剂，继续反应3h。然后与乙二醛在85℃下，反应2h即得产品。    
    (2)成膜性测试表明，当w(PVA)=8.0%、w(乙二醛)=3.5%、w(异丙醇)=0.5%时，胶乳膜具有较好的力学性能和耐水性，拉伸强度(σ)和断裂伸长率(ε)分别为8.520 MPa和40%以上，水接触角可达到92.5°。
    (3)流变性测试表明，改性阳离子丙烯酸树脂乳液为非牛顿流体，有一定的假塑性和触变性，表观粘度随切变速率的变化规律呈现一定的切力变稀特征，流动指数范围n为0.982~0.675之间，随w (PVA)、w (DMC)、w (乙二醛)、w (异丙醇)的不同而异。乳液的表观粘度随w (PVA)和w (乙二醛)的增加而增加；随w (DMC)的增加而降低；助溶剂的加入改善了乳液的流动性。
    (4)红外光谱(FT-IR)分析证实了树脂中各单体单元的存在，试验成功制得改性阳离子丙烯酸树脂。透射电镜(TEM)分析可知乳胶粒分布呈规则球状，表面光滑洁净，分布均一。动态激光光散射(DLLS)分析可知树脂乳液的平均粒径为165.7nm。广角X射线衍射(WAXD)谱图显示有一弥散形宽峰，表明改性阳离子丙烯酸树脂属于非晶态聚合物。差示扫描量热(DSC)测定结果显示聚合物的玻璃化转变温度为50.3℃。热重(TG)分析表明，聚合物的起始分解温度为150℃左右，可以满足一般造纸工艺的温度要求。原子力显微镜(AFM)分析表明树脂成膜表面相对平整、光滑，且均匀。
    (5)将所制备的改性阳离子丙烯酸树脂用在造纸工业，其可用于表面施胶，也可用于浆内施胶。两种处理方法均可以赋予纸张一定的防水性，并改善纸张的强度性能。纸张表面施胶应用实验表明，单独使用该聚合物施胶剂，纸张的抗张强度、耐折度、平滑度、白度分别提高22.32%、38.2%、20.25%、1.71%，且与氧化淀粉复配使用的效果均接近于或高于单独使用聚合物乳液的纸张。纸张浆内施胶应用实验表明，在较宽pH值下施胶剂用量为1.5%左右时纸张性能较好。通过SEM可观测到共聚物处理后的纸页纤维编织紧密，纤维间发生粘结，空隙率降低。
    以上研究表明，通过无皂乳液聚合可制备出具有强阳离子性、无乳化剂、乳胶粒分布较为均一、表面光滑洁净的改性阳离子丙烯酸树脂乳液；乳液为非牛顿流体，有一定的假塑性和触变性，流变性好，便于施胶；乳胶膜的耐水性和力学性能较好；该树脂作为表面施胶剂或浆内施胶剂在造纸工业上都具有较好的应用效果。

外文论文文摘

    With the action of catalyst and cosolvent, using polyvinyl alcohol (PVA) as dispersing agent and glyoxal as crosslinker modified cationic acrylic resin were prepared by emulsifier-free copolymerization with styrene(St), butylacrylate(BA), methacryloxyethyl trimethylammonium chloride(DMC), methacrylic acid(MAA) and octadecyl acrylate(ODA) as main monomers. Their structure, morphology and performance were characterized by various modern analysis methods. Effects of w(PVA), n(BA)/n(St), w(DMC)，w(MAA) and w(glyoxal) on the particle size and size distribution of resin emulsions and the sizing value and galling speed of papers were studied. And effects of w(PVA), n(BA)/n(St), w(crosslinker) and w(solvent) on the emulsion’s rheological properties were analyzed. Finally, the factors that affect the mechanical properties and water resistant performance of the membranes were discussed.
    The modified cationic acrylic resin can be used in surface and internal sizing, the sizing progress and the function mechanism are discussed at last.
    The main results are shown as follow:
1.The optimum reaction condition was described as below: seed semi-batch polymerization. w(DMC)=10%，w(PVA)=8%，w (catalyst)=0.2%，w (MAA)=5%，n(BA)：n(St)=1.1：1，w (ODA)=0.8%, w (glyoxal)=3.5%, w (isopropanol)=0.5%. Polymerization temperature: 80℃.1/4 monomers and 1/3 initiators was firstly added into flask. After 1 hour, the rest of monomers and initiators were added into the flask by drop-wise addition process in 1 hour followed by an additional 3 hour of reaction. Then it reacted with glyoxal in 2 hours at the temperature of 85℃.
2.The result of film-forming test shows that the mechanical properties and water resistant performance of the membranes are better under the condition of w(PVA)=8.0%、w(glyoxal)=3.5%、w(isopropanol)=0.5%, that is, the tensile strength(σ) and the elongation at break are 8.520 MPa and more than 40% respectively, and water contact angle can receive 92.5°.
3.The result of rheology test shows that the modified cationic acrylic resin emulsion is non-Newtonian fluid, exhibits endowed with pseudoplasticity and thixotropy. It is noticed that the apparent viscosity decreases with increasing the shear rate, that is, the emulsions show a characteristic of shear thinning, and their flow-behavior index (n) ranges from 0.982 to 0.675, changing with w(PVA)、w(DMC)、w(glyoxal)、w(isopropanol). The emulsions’ apparent viscosity are increased by the increase of the w(PVA) and w(isopropanol), decreased by the increase of w(DMC), and the emulsions’ rheological properties are approved by the addition of the cosolvent.
4.The Fourier transform infared spectrometer (FT-IR)  indicates the exist of the structure of monomers of the resin, the modified cationic acrylic resin is successfully prepared. The transmission electron microscope (TEM) indicates that the latex particles are regular sphericity, the surface of the particles is clean. The dynamic laser light scattering (DLLS) indicates that the average diameter of the particles is 165.7nm. The wide-angle X-ray diffraction (WAXD) diagram indicates that the modified cationic acrylic resin is amorphous polymer. The differential scanning calorimeter (DSC) diagram shows that the glass transition temperature of the polymer is 50.3℃. The thermogravimetry (TG) indicates that the original decomposition temperature of the resin is near 150℃, this temperature is fit for general technics of paper making. The atomic force microscopy (AFM) indicates that the surface of the membrane of the resin is relatively leveling, smoothing, and even.
5.The modified cationic acrylic resin is used in paper-making as surface and internal sizing agents. The two methods both can endow the paper with good water repellency performance, at the same time the paper’s strength properties are raised. The surface sizing application result shows that the paper’s tensile strength, fracture-resist degree, smoothness degree and whiteness were respectively increased by 22.32%、38.2%、20.25%、1.71%, and the effects are close to or higher than single polymer emulsion when the oxidized starch and polymer emulsion are used as a complex system in different proportions. The surface sizing application result shows that, paper performace is better when the dosage of resin is about 1.5% in wide pH range. The scanning electron microscope (SEM) spectrums of the papers indicate the function of the emulsion.
    Learned from the results, the preparation technology of the stable modified cationic acrylic resin emulsion by soap-emulsion copolymerization is possible and successful. Emulsion is non-Newtonian fluid, exhibits endowed with pseudoplasticity and thixotropy; and its rheological properties is good, so it is good to paper sizing. The mechanical properties and water resistant performance of the membranes are better. The application of this resin is good as surface sizing agent and internal sizing agent in paper-making.