MBS接枝共聚物对PMMA树脂的增韧研究

采用乳液聚合法在聚丁二烯（PB）乳胶粒子上接枝苯乙烯（St）和甲基丙烯酸甲酯(MMA),合成了一系列的MBS接枝共聚物（简称MBS）,将其与聚甲基丙烯酸甲酯（PMMA）进行熔融共混制备PMMA/MBS共混物,研究了PB及相对分子质量调节剂叔十二烷基硫醇（TDDM）含量对共混物力学性能和微观形态结构的影响。结果表明,随着MBS中PB所占比例的增加,共混物的冲击强度表现出先增大后减小的趋势,当PB所占比例为50 %（质量分数,下同）时,共混物的冲击强度达到200 J/m,而拉伸强度表现出上升的趋势;随着TDDM用量的增加,MBS的接枝率和接枝效率降低,导致共混物的冲击强度先增加后减小;随着MBS中PB所占比例的增加,接枝率的逐渐降低,MBS在PMMA基体中分散程度逐渐变差。     

苯乙烯在MBS中的结合方式对PVC/MBS性能的影响

以乳液聚合法合成了化学组成恒定的具有核-壳结构的(甲基丙烯酸甲酯/丁二烯/苯乙烯)共聚物(MBS),通过改变原料及其配比,使苯乙烯(St)在MBS中以共聚或接枝方式结合,用动态力学热分析仪研究了MBS内耗与温度的关系。将MBS与聚氯乙烯(PVC)共混,研究了St结合方式对共混物冲击韧性及增韧机理的影响,结果表明,随着MBS核中St含量的增加,PVC/MBS共混物的脆-韧转变向高温移动;当St仅以接枝的方式结合时,橡胶粒子的空洞化及剪切屈服是主要的增韧机理,当St仅以共聚方式结合时,剪切屈服是主要的增韧机理。     

马来酸酐官能化ASA对PA6的增韧研究

采用乳液聚合法制备了一系列马来酸酐（MAH）官能化的丙烯酸丁酯橡胶（PBA）与苯乙烯（St）及丙烯腈（AN）的接枝共聚物（PBA-g-SAN）核壳结构改性剂（ASA-g-MAH）,用于聚酰胺6(PA6)的增韧。Molau实验证实了PA6/ASA-g-MAH共混体系中存在化学反应,考察了MAH含量对共混体系结构和性能的影响。结果表明,随着MAH含量的增加,PA6/ ASA-g-MAH共混物的冲击强度逐渐增大,当MAH含量为4 %（质量分数,下同）时材料冲击强度达到1008 J/m;与PA6/ASA共混物相比,PA6/ASA-g-MAH共混物具有较高的拉伸强度和断裂伸长率;随着MAH含量的增加,ASA- g-MAH在PA6基体中的分散程度越来越好,当MAH含量达到4 %以上时,无聚集现象发生;ASA-g-MAH中橡胶粒子的空洞化和PA6基体的剪切屈服是主要的增韧机理。     

改性剂核壳比对增韧聚乳酸性能的影响

采用乳液聚合方法合成了以甲基丙烯酸甲酯(MMA)-苯乙烯(St)-甲基丙烯酸缩水甘油酯(GMA)共聚物为壳,聚丁二烯(PB)为核的反应性核壳粒子(RCS),研究RCS粒子核壳比变化对增韧聚乳酸(PLA)性能的影响。随着核壳比的增加,RCS粒子接枝度和粒子尺寸逐渐降低。扫描电镜(SEM)观察发现,RCS粒子在PLA中可以均匀分散;动态力学性能测试表明随着核壳比的增加,RCS壳层共聚物玻璃化温度向低温移动,核壳粒子与PLA相容性较好;力学测试结果表明,随着核壳比的增加,PLA共混物的韧性显著提高,当核壳比大于50/50后,共混物缺口冲击强度可以达到630 J/m左右,拉伸屈服强度则有所降低。     

一种新型交联剂对ACR增韧PVC的影响

采用二甲基丙烯酸乙二醇酯（EGDMA）作为一种新型交联剂,以种子乳液聚合方法合成了一系列不同交联剂含量的丙烯酸酯类核壳增韧改性剂（ACR）,用于对聚氯乙烯（PVC）树脂的增韧改性研究。通过改变交联剂的含量,测试了ACR的交联度、接枝度、接枝效率和玻璃化转变温度（Tg）。研究了ACR/PVC共混物的力学性能与交联剂含量之间的关系。数据显示：当交联剂含量增加时,ACR的交联度、接枝度、接枝效率和玻璃化转变温度都得到了升高。当交联剂含量为0.4%,ACR/PVC的质量比为8/100时,ACR/PVC共混物发生了脆韧转变,冲击强度为1145J/m,是纯PVC的39倍。     

P(BA-g-MMA)/纳米蒙脱土复合粒子的制备及其增韧PVC的研究

采用种子乳液聚合法制备了纳米蒙脱土(MMT)改性聚丙烯酸丁酯甲基丙烯酸甲酯核壳接枝共聚物P(BA-g-MMA)增韧剂并用于增韧聚氯乙烯（PVC）树脂,分析了MMT含量对共混物力学性能的影响,用X射线衍射仪、扫描电子显微镜观察了蒙脱土的插层和分散效果。结果表明,丙烯酸丁酯(BA)单体在MMT层间发生聚合反应,使MMT层间距由1.25 nm增大至1.5 nm;当P(BA-g-MMA)核壳比(BA∶MMA)为85∶15,100 份（质量份,下同） PVC中加入9份P(BA-g-MMA)时,PVC/P(BA-g-MMA)共混物冲击强度为1106 J/m,是典型的韧性断裂,综合性能好。     

AIM增韧剂的合成及其增韧PVC的研究

采用种子乳液聚合法合成了核-壳结构丙烯酸酯类冲击改性剂(AIM),并用其增韧聚氯乙烯(PVC)树脂。采用动态激光粒度分析仪、DMA测试了AIM的乳胶粒子尺寸和玻璃化转变温度。对PVC/AIM共混物力学性能的分析表明:当PVC/AIM=100/8时,通过调节AIM交联剂含量和粒子尺寸,可以使PVC/AIM共混物冲击强度达到1443J/m。     

ACR-g-St的制备及对PVC增韧

采用乳液聚合法制备了苯乙烯改性的核壳结构丙烯酸酯增韧剂(ACR-g-St),将其与聚氯乙烯(PVC)共混制备了增韧PVC共混物,采用动态热机械分析和扫描电镜等方法研究了PVC/ACR-g-St共混体系力学性能和相结构。结果表明,PS能增加PVC与ACR-g-St二者间的分子链缠结,当ACR-g-St用量为8phr时,PVC共混物的冲击强度为950J/m,是韧性断裂;扫描电镜照片表明ACR粒子在PVC基体中分散均匀。     

PVC/SBS/MBS三元共混体系的力学性能及光学透明性研究

采用冲击实验、拉伸实验、超景深三维显微镜、扫描电镜和分光光度计等手段，对PVC／SBS／MBS三元共混体系的冲击强度、拉伸强度、形态结构以及光学透明性等进行了研究。实验结果表明，MBS能有效改善PVC／SBS共混体系的界面相容性。当SBS和MBS的总量不变时，随着MBS相对含量的增加，共混体系的缺口冲击强度逐渐增加，透光率在m（MBS）／m（SBS）=28／80时达到最大值，光学透明性能最好。     

PVC/ACR共混物结构与性能的研究

采用乳液聚合技术合成一系列具有核-壳结构的丙烯酸酯类抗冲改性剂(ACR),将其与聚氯乙烯(PVC)进行熔融共混制备PVC/ACR共混物。研究ACR的核/壳比、橡胶的粒子尺寸和交联剂三烯丙基异三聚氰酸酯(TAIC)含量对PVC/ACR共混物力学性能与形态结构的影响。结果表明,随着核/壳比的增大,ACR的增韧效率有了明显的提高;交联剂的加入改变了ACR的刚性与韧性,进而对共混物的性能有了较大的影响,随着交联剂含量的增加,共混物的冲击强度先变大后减小,当交联剂的含量为4%,ACR的添加量为8 phr时,共混物的冲击强度达到了1 196.70 J/m;随着橡胶粒子尺寸的增加,共混物的韧性逐渐降低。扫描电子显微镜分析表明,ACR增韧PVC的主要增韧机理是橡胶的空洞化和基体的剪切屈服。     

Phase morphology and dynamic mechanical behavior for MIS toughened polyvinyl chloride

Graft copolymers of isoprene (Is), styrene (St), and methyl methacrylate (MMA) monomers (MIS) with typical core–shell structure were synthesized by seed emulsion polymerization and used as a toughening agent for preparation of polyvinyl chloride (PVC)/MIS blends. The St and MMA monomers were separately grafted on the cross‐linked poly‐isoprene rubber core. The toughness, sub‐micro‐morphology, and dynamic mechanical behavior of the blends were characterized by impact machine, scanning electron microscopy (SEM), and dynamic mechanical analyzer. The results showed that the impact strength of the blends was optimized when the content of MIS in PVC/MIS blends was kept at a constant value of 8 wt %, while the content of Is in MIS was 70 wt %. SEM morphologies of impact fractured surface showed that the PVC/MIS blends were typical ductile fracture because of the toughness effect of rubber particles, which correlated well with the mechanical properties. Under the same rubber content condition, the curves of the dynamic mechanical behavior of MIS toughened PVC blends appeared a more obvious rubber peak, indicating that the rubber content of MIS was higher than that of methyl methacrylate–butadiene–styrene (MBS), which explained the better toughening effect of MIS compared with MBS. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

The toughness and morphology of (chlorinated poly[vinyl chloride])/(methyl methacrylate‐butadiene‐styrene) blends

A series of methyl methacrylate‐butadiene‐styrene (MBS) graft copolymers were synthesized via seeded emulsion polymerization techniques by grafting styrene and methyl methacrylate on poly(butadiene‐co‐styrene) (SBR) particles. The chlorinated poly(vinyl chloride) (CPVC)/MBS blends were obtained by melting MBS graft copolymers with CPVC resin, and the effect of the core/shell ratio of MBS graft copolymer and SBR content of CPVC/MBS blends on the mechanical properties and morphology of CPVC/MBS blends was studied. The results showed that, with the increase in the core/shell ratio, the impact strength of the blend increased and then decreased. It was found that, when the core/shell ratio was 50/50, the impact strength was about 155 J/m, and the tensile strength evidently increased. The toughness of the CPVC/MBS blend was closely related to the SBR content of the blend, and with the increasing of SBR content of blend, the impact strength of the blend increased. The morphology of CPVC/MBS blends was observed via scanning electron microscopy. Scanning electron microscopy indicated that the toughness of CPVC/MBS blend was consistence with the dispersion of MBS graft copolymers in the CPVC matrix. J. VINYL ADDIT. TECHNOL., 22:501–505, 2016. © 2015 Society of Plastics Engineers     

MBS核-壳粒子的内部结构对MBS/PVC光学性能的影响

以乳液聚合的方法合成了具有核-壳结构的MBS树脂。恒定MBS中M/B/S的比例为30/42/28,通过采用不同的引发体系及加料方式制备不同内部结构的橡胶粒子。将MBS树脂与聚氯乙烯（PVC）共混,研究了橡胶粒子的内部结构对共混物透光性的影响。用透射电子显微镜对共混物的形态进行了研究,MBS粒子分别具不同的包容物结构。研...     

Effects of core‐shell particle growth manners on morphologies and properties of poly(vinyl chloride)/(methyl methacrylate–butadiene–styrene) blends

A series of methyl methacrylate‐butadiene‐styrene (MBS) core‐shell particles were synthesized by seeded emulsion polymerization. All the MBS particles are designed with the same defined chemical composition, which is a prerequisite for producing transparent blends with poly(vinyl chloride) (PVC). Three different growth manners of core‐shell particles: agglomeration of small styrene‐butadiene rubbers (SBRs) followed by styrene (ST) and methyl methacrylate (MMA) monomers grafting, agglomeration of small MBS particles and traditional MBS with single SBR rubber core, and ST/MMA shells are used. The effects of growth manners of MBS on the properties and deformation mechanism of PVC/MBS blends are studied. It is found that all the MBS particles can toughen the PVC matrix effectively, but different deformation modes are observed: cavitation in large particles, debonding at the PVC/MBS interface, rubber cavitation, and clusters of voids, respectively. In addition, it is found that the stress‐whitening extent is associated with the deformation modes. J. VINYL ADDIT. TECHNOL., 22:37–42, 2016. © 2014 Society of Plastics Engineers     

Facile preparation of nylon 6 nanocomposites based on clay reinforcement and core‐shell latex toughening: Morphology,properties, and impact fracture behavior

This work is focused on a facile route to prepare a new type of nylon 6‐based nanocomposites with both high fracture toughness and high strength. A series of nylon 6‐matrix blends were prepared via melting extrusion by compounding with poly (methyl methacrylate‐co‐butadiene‐co‐styrene) (MBS) or poly(methyl methacrylate‐co‐methylphenyl siloxane‐co‐styrene) (MSIS) latices as impact modifier and diglycidyl ether of bisphenol‐A (DGEBA) as compatibilizer. Layered organic clay was also incorporated into above nylon 6 blends for the reinforcement of materials. Morphology study suggests that the MBS or MSIS latex particles could achieve a mono‐dispersion in nylon 6 matrix with the aid of DGEBA, which improves the compatibilization and an interfacial adhesion between the matrix and the shell of MBS or MSIS. High impact toughness was also obtained but with a corresponding reduction in tensile strength and stiffness. A moderate amount of organic clay as reinforcing agent could gain a desirable balance between the strength, stiffness and toughness of the materials, and tensile strength and stiffness could achieve an improvement. This suggests that the combination of organic clay and core‐shell latex particles is a useful strategy to optimize and enhance the properties of nylon 6. Morphology observation indicates that the layered organic clay was completely exfoliated within nylon 6 matrix. It is found that the core‐shell latex particles and the clay platelets were dispersed individually in nylon 6 matrix, and no clay platelets were present in MBS or MSIS latex particles. So the presence of the clay in nylon 6 matrix does not disturb the latex particles to promote high fracture toughness via particle cavitation and subsequent matrix shear yielding, and therefore, provides maximum reinforcement to the polymer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

甲基丙烯酸甲酯-丁二烯-苯乙烯树脂的合成及其对聚氯乙烯的改性

采用种子乳液接枝聚合技术合成了甲基丙烯酸甲酯(MMA)-丁二烯-苯乙烯树脂(MBS),考察了复合乳化剂浓度、CO2用量对丁苯胶乳粒径及其分布、胶乳稳定性的影响;研究了接枝单体滴加方式和接枝聚合反应温度对MBS体系稳定性和接枝效率的影响;讨论了MBS改性聚氯乙烯(PVC)的影响因素;提出了丁苯胶乳的碳酸化扩径附聚法和MBS胶乳的SO2凝聚新工艺。结果表明:在丁二烯/苯乙烯(质量比)为90/10、阴离子/非离子复合乳化剂浓度为35~40g/L、丁苯胶乳采用CO2附聚扩径、部分MMA预溶胀和其余MMA连续滴加的方式以及MBS胶乳SO2凝聚新工艺的条件下,所得MBS树脂粉料颗粒均匀,40~180目的颗粒质量分数达96%,堆积密度在0.4g/cm3以上;PVC/MBS(质量比为100/8)共混物的冲击强度达22.6kJ/m2。     

MBS粒子尺寸对PVC／MBS共混物性能及形变机理的影响

通过乳液聚合方法制备了两种不同粒径（分别为270nm和80nm）的甲基丙烯酸甲酯/丁二烯/苯乙烯（MBS）核壳改性剂，与聚氯乙烯（PVC）进行熔融共混，得到了PVC／MBS共混物。对PVC／MBS共混物力学、光学等方面的性能及其形变机理分别进行了考察。结果表明：PVC／MBS共混物的脆-韧转变温度（BDT）和拉伸性能均随着MBS粉料粒径的增加而增加；但是光学测试则表明MBS粒子对改善PVC基体的光学性能的效果却随MBS粉料粒径的增加而降低；透射电镜（TEM）的分析表明大粒径的MBS粉料能促使橡胶粒子产生空洞化，而由小粒径的MBS粉料制备的PVC／MBS共混物没有观察到橡胶粒子空洞化的产生。     

The influence of the internal structure of core–shell particles on poly(vinyl chloride)/(methyl methacrylate–butadiene–styrene) blends

Methyl methacrylate–butadiene–styrene (MBS) core–shell particles were prepared by grafting styrene and methyl methacrylate onto polybutadiene seeds via emulsion polymerization. All the MBS particles were designed with the same chemical composition, similar grafting degree but different internal structures. The difference in internal structure was realized by controlling the ratio of ‘external grafting’ and ‘internal grafting’ of styrene. The work focused on the influence of the internal structure of MBS core–shell particles on the properties of poly(vinyl chloride)/MBS blends. From transmission electron microscopy, three different internal structures were observed: rare sub‐inclusions, a large number of small sub‐inclusions and large sub‐inclusions. The results of dynamic mechanical analysis illustrated that the different internal structures greatly affected the glass transition temperature T_g of the rubber phase and the storage modulus of the core–shell particles. The notched Izod impact test results showed that the MBS with large sub‐inclusions had the lowest brittle–ductile transition temperature, while the transparency test revealed that the presence of sub‐inclusions in the rubbery phase reduced the transparency of the blend. Copyright © 2012 Society of Chemical Industry