乙烯-1-丁烯共聚物为橡胶相的抗冲共聚聚丙烯的结构

通过核磁共振波谱仪、凝胶渗透色谱仪、差示扫描量热仪、扫描电子显微镜等对乙烯-1-丁烯共聚物为橡胶相的抗冲共聚聚丙烯的结构进行了分析,并测试了其模塑收缩率及耐应力发白性能。结果表明:乙烯-1-丁烯共聚物可溶物的相对分子质量较低时,所制抗冲共聚聚丙烯在注塑过程中易受到剪切应力作用而沿熔体流动方向形成柱状取向结构,此橡胶相取向结构赋予抗冲共聚聚丙烯低模塑收缩率和良好的耐应力发白性能;乙烯-1-丁烯共聚物可溶物的相对分子质量较高时,所制抗冲共聚聚丙烯在注塑过程中则呈现典型的"海-岛"状橡胶形态,因而表现出较高的模塑收缩率和较差的耐应力发白性能。     

富勒烯-钕系催化剂引发丁二烯-异戊二烯共聚合

研究了富勒烯-钕系催化剂在加氢汽油中引发丁二烯和异戊二烯共聚合的反应规律。结果表明，当C60Cln(简称Cl)／Nd(naph)，(简称Nd，摩尔比)为1～9时，富勒烯-钕系催化剂与加氢汽油皆形成均相体系，最佳陈化方式[Al(i—Bu)，(简称Al) Cl] Nd，催化活性随陈化时间延长(直到4h)和陈化温度升高(直到80℃)而增大，表明该催化剂稳定性较好；其共聚物特性黏数为1．5—2．5dL／g，低于Nd—Al—Cl催化体系；相对分子质量分布较窄(2～4)。经傅里叶变换红外光谱和核磁共振测定，确认产物为无规共聚物。聚丁二烯链段为顺-l，4-结构，聚异戊二烯链段为顺-l，4-结构和3，4-结构。     

国外抗冲共聚聚丙烯结构的研究

利用升温淋洗分级柱、核磁共振波谱仪、差示扫描量热仪、凝胶渗透色谱仪和扫描电子显微镜等研究了国外抗冲共聚聚丙烯(PP)的组成、序列结构、相对分子质量及其分布、热转变、相态结构和宏观性能.结果表明,该抗冲共聚PP由均聚PP、乙丙橡胶和可结晶的乙丙共聚物组成,具有优良的机械性能;均聚PP为抗冲共聚物提供刚性,乙丙橡胶可提高抗冲共聚物的韧性;抗冲共聚物的相对分子质量呈多分散性,其分布较宽;乙丙橡胶的相对分子质量较大,以直径为1～2μm的微粒均匀分布在PP基体中,有利于提高抗冲共聚物的冲击强度;抗冲共聚物的熔点较高,耐热性好.     

低熔抗冲共聚聚丙烯结构对其力学性能的影响

考察了低熔抗冲共聚聚丙烯(IPC)的结构、橡胶相与均聚相的相容性、结晶性能对材料力学性能的影响。结果表明:提高橡胶相含量、增大橡胶相特性黏数、改善橡胶相和均聚相的相容性、提高乙烯含量、减小球晶尺寸均可提高低熔IPC产品的冲击强度;在聚合过程中生成的可结晶聚乙烯会降低低熔IPC产品的冲击强度;低熔IPC产品的弯曲模量随着均聚部分结晶度的提高而增大。     

PCL及PCL-PEG-PCL共聚物的合成与表征

以辛酸亚锡[Sn(Oct)2]作为引发剂,采用ε-己内酯(ε-CL)开环均聚合制备聚ε-己内酯(PCL),考察了n(ε-CL)/n[Sn(Oct)2]、反应温度和反应时间等因素对聚合产物特性黏数的影响。以Sn(Oct)2为催化剂,聚乙二醇(PEG)为引发剂,合成了不同相对分子质量的PCL-PEG-PCL三嵌段共聚物,研究了ε-CL均聚物及共聚物的结构、热性能和结晶形态。PCL最佳合成工艺为:n(ε-CL)/n[Sn(Oct)2]为400,温度130℃,反应时间4 h。随着PEG相对分子质量从2×103增加到8×103,三嵌段共聚物的熔融温度、熔融焓和结晶温度逐渐升高;结晶温度及PEG相对分子质量对PCL-PEG-PCL三嵌段共聚物球晶的形态和尺寸影响很大。     

低相对分子质量反-1,4-聚异戊二烯蜡的分级与表征

以负载型TiCl4/MgCl2-Al(i-Bu),为催化剂,1．48MPa氢气为相对分子质量调节剂,采用本体淤浆聚合法,制备了重均相对分子质量及其分布分别为42700和50,特性黏数为0．697dL/g的低相对分子质量反-1,4-聚异戊二烯蜡(LMTPIW),并对其级分进行了表征。结果表明,随着教均相对分子质量的降低,LMTPIW的熔体流动性增加,结晶度下降,熔点降低,反-1,4-结构摩尔分数下降,但基本在90％以上,3,4-结构摩尔分数为1．0％～1．5％。当数均相对分子质量超过860时,LMTPIW由黏性转变为脆性;大于1800时,又转变为韧性物质。所得LMTPIW为相对分子质量分布宽、结构性能差异较大的分子混合物。     

高抗冲聚丙烯结构对冲击性能的影响

利用聚丙烯中试装置制备性能不同的抗冲共聚聚丙烯,考察了抗冲共聚聚丙烯结构、分子量及分子量分布、橡胶相与均聚相的相容性、橡胶相分散状态对产品冲击性能的影响。结果表明:增大橡胶相特性粘数,增加橡胶相中大分子含量,提高橡胶相和均聚相的相容性,橡胶相以相近的尺寸均匀分散在均聚相中都有利于产品冲击强度的提高。     

抗冲聚丙烯1215C的结构研究

采用分析型升温淋洗仪(A-TREF)研究了抗冲聚丙烯1215C的化学组成分布,利用制备型升温淋洗仪(P-TREF)、核磁共振仪(NMR)、差示扫描量热仪(DSC)、高温凝胶色谱(GPC)等方法研究了抗冲聚丙烯1215C的组分含量、序列结构、相对分子质量、热行为。结果表明:P-TREF所得7个组分中,第1个组分质量分数21.64%,具有典型的乙丙橡胶结构,相对分子质量较高且分布窄。第2~4个组分质量分数共计7.51%,主要为长乙烯链段的乙丙共聚物,含有少量低相对分子质量聚丙烯,相对分子质量较大且分布宽。第5个组分质量分数为4.38%,是91.83%较低相对分子质量聚丙烯和8.17%聚乙烯组成的混合物。第6~7组分为聚丙烯均聚物,质量分数为66.02%,相对分子质量较高且分布窄。     

钯的二亚胺催化剂催化1-辛烯乳液聚合

以钯的二亚胺为催化剂,在乳液体系中催化1-辛烯均聚合及1-辛烯与丙烯酸甲酯(MA)共聚合。通过光散射分析仪、差示扫描量热仪、凝胶渗透色谱仪、核磁共振谱仪测定了聚合物的粒径、熔点、相对分子质量,表征了其结构。结果表明:该催化剂在乳液体系中可以催化1-辛烯均聚合及1-辛烯与MA的共聚合;聚合物相对分子质量可达2.30×104以上,且相对分子质量分布(1.0～2.0)较窄,共聚物中MA与1-辛烯的摩尔比高达1.0∶4.5;均聚物的支化度(81.8个/1 000 C)和共聚物的支化度(112.8个/1 000 C)均较高;共聚物为半结晶型共聚物,其玻璃化转变温度为-57℃,熔点为83℃。     

适用于轮胎胎面胶的橡胶

由台湾合成橡胶股份有限公司申请的专利(专利号　 971 2 2 941 ,公布日期　 1 999 0 7 1 4)“适用于轮胎胎面胶的橡胶” ,其组成包括 :①质量分数为 0 1 0～ 0 50的共轭二烯和乙烯基芳香烃共聚物或共轭二烯单聚物 (经锡、磷、镓和硅等化合物偶合 ) ,相对分子质量为 5万～ 3 5万 ;②质量分数为 0 1 0～ 0 60的共轭二烯和乙烯基芳香烃共聚物 (未经偶合 ) ,相对分子质量为 1 0万～ 80万 ;③质量分数为 0 50～ 0 60的共轭二烯和乙烯基芳香烃共聚物 (经锡、磷等化合物偶合 ) ,相对分子质量为 45万～ 2 0 0万。适用于轮胎胎面胶的橡胶…     

聚(丙烯酸钠-4-乙烯基吡啶)的表征

为了改善生物分解性能，在聚丙烯酸钠主链上引入了少量4-乙烯基吡啶，并对共聚产物进行了IR、UV、元素分析、热稳定性、螯合性能、分散性能等研究。结果表明，共聚产物中原来的吡啶环已经质子化，形成两性离子聚合物，聚合物的热稳定性随着原料中4-乙烯基吡啶含量的增加而下降，当4-乙烯基吡啶的物质的量分数为6％左右时，共聚物的粘均分子量大约1．3万，共聚物具有较好的螯合性能和分散性能。     

Influence of polymeric flame retardants based on phosphorus‐containing polyesters on morphology and material characteristics of poly(butylene terephthalate)

Flame retarded poly(butylene terephthalate) (PBT) is required for electronic applications and is mostly achieved by low molar mass additives so far. Three phosphorus‐containing polyesters are suggested as halogen‐free and polymeric flame retardants for PBT. Flame retardancy was achieved according to cone calorimeter experiments showing that the peak heat release rate and total heat evolved were reduced because of flame inhibition and condensed‐phase activity. The presented polymers containing derivatives of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide form immiscible blend systems with PBT. Shear‐rheology shows an increase in storage moduli at low frequencies. This is proposed as quantitative measure for the degree of phase interaction. The phase structure of the blends depends on the chemical structure of the phosphorus polyester and was quite different, depending also on the viscosity ratio between matrix and second phase. A lower viscosity ratio leads to two types of phases with spherical and additionally continuous droplets. Addition of the flame retardants showed no influence on the dielectric properties but on the mechanical behavior. The polymeric flame retardants significantly diminish the impact strength because of several reasons: (1) high brittleness of the phosphorus polyesters themselves, (2) thermodynamic immiscibility, and (3) weak phase adhesion. By adding a copolymer consisting of the two base polymers to the blend, an improvement of impact strength was obtained. The copolymer particularly acts as compatibilizer between the phases and therefore leads to a smaller phase size and to a stronger phase adhesion due to the formation of fibrils. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effects of the viscosity ratio on polyolefin ternary blends

Polyolefin binary and ternary blends were prepared from polypropylene (PP), an ethylene–α‐olefin copolymer (mPE), and high‐density polyethylene (HDPE) on the basis of the viscosity ratio of the dispersed phase to the continuous phase. In PP/mPE/HDPE blends, fibrils were observed when the dispersed‐phase (mPE/HDPE) viscosity was less than that of PP, or when the viscosity of mPE was less than that of PP, although the viscosity of mPE/HDPE was greater than that of PP. The notched impact strength and mechanical properties such as the yield strength, flexural modulus, and hardness of PP/mPE binary blends further increased with the addition of HDPE according to the type of HDPE. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 4027–4036, 2004     

Melt viscosity and electrical conductivity of carbon black-PVC composite

The effect of the structure of carbon black aggregates on the melt behavior and electrical conductivity of carbon black-vinylchloride-vinylacetate copolymer systems was analyzed. As the amorphous carbon aggregates are roll-milled, they become cylindrical, then, as the milling time is prolonged, spherical. During milling, polymer adsorption and dispersivity increases in the same manner, causing the viscosity of the composite to decrease. It was established that during a certain milling time, conductivity rises to a peak, after which it falls. We attribute this phenomenon to there being an optimum aspect ratio and degree of dispersion of the cylindrical carbon aggregates. A model explaining the relationship between milling time and change in conductivity is proposed. When oxidized carbon black was dispersed into the copolymer, it was found that it disperses better than unoxidized carbon black, although the conductivity of the resulting composite is lower.     

Preparation and properties of amphoteric polyacrylamide by seeded dispersion polymerization in ammonium sulfate solution

Amphoteric polyacrylamide (AmPAM) was prepared successfully through seeded dispersion polymerization with acrylamide, methacrylatoethyl trimethyl ammonium chloride and acrylic acid as comonomers in ammonium sulfate solution. It was characterized by ¹H nuclear magnetic resonance (¹H NMR) and elemental analysis. The particle morphology and apparent viscosity of polymer dispersion were obtained by optical microscope and rotary viscometer, respectively. AmPAM dispersion was obtained with low apparent viscosity. The process was smooth without high viscosity stage. The data of ¹H NMR spectrum and elemental analysis indicated that all monomers had participated in the polymerization. The seeded reaction time and the mass ratio of two parts of monomers had significant effects on the dispersion polymerization. The best conditions were seeded reaction time 1.75h and the mass ratio 0.75. The apparent viscosity of AmPAM dispersion depended on the number of particles, particle size and low molecular weight polymer concentration in the continuous phase. AmPAM showed both anti‐polyelectrolyte effect and polyelectrolyte effect. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

AA-AMPS共聚物陶瓷分散剂的制备及分散性能

以丙烯酸和2-丙烯酰胺基-2-甲基-丙烷磺酸(AMPS)为单体,过硫酸铵(NH4)2S2O8作为引发剂,次亚磷酸氢钠作为链转移剂,通过自由基聚合反应合成共聚物PAA-AMPS。探讨了不同反应条件对共聚物分散性能的影响,共聚物分散剂PAA-AMPS的最佳合成条件为:丙烯酸(AA)与2-丙烯酰胺基-2-甲基-丙烷磺酸(AMPS)的摩尔比为8∶1;引发剂(NH4)2S2O8用量为单体总质量的1%;链转移剂次亚磷酸氢钠的用量为单体总质量的10%;单体质量分数为24%;反应温度85℃。通过FTIR、GPC及1HNMR等手段对共聚物的结构及相对分子质量及其分布进行了表征,并对添加不同量分散剂的料浆的黏度进行研究。结果表明,聚合物质量分数为0.3%,料浆的黏度最低,与进口产品PC-67(PAA-Na)相比,共聚物PAA-AMPS的分散效果更好。     

Phase morphology and melt rheological behavior of uncrosslinked and dynamically crosslinked polyolefin blends: role of macromolecular structure

Thermoplastic vulcanizates (TPVs) based on polypropylene (PP) with ethylene–octene copolymer (EOC) and ethylene propylene diene rubber (EPDM) have been prepared by co-agent-assisted peroxide crosslinking system. The study was pursued to explore the influence of two dissimilar polyolefin polymers having different molecular architecture on the state and mode of dispersion of the blend components and their influence on melt rheological properties. The effects of dynamic crosslinking of the PP/EOC and PP/EPDM have been compared with special reference to the concentration of crosslinking agent and ratio of blend components. Morphological analyses show that, irrespective of blend ratio, dynamic vulcanization exhibits a dispersed phase morphology with crosslinked EOC or EPDM particles in the continuous PP matrix. It was found that viscosity ratio plays a crucial role in determining the state and mode of dispersion of blend components in the uncrosslinked system. The lower viscosity and torque values of uncrosslinked and dynamically crosslinked blends of PP/EOC in the melt state indicates that they exhibit better processing characteristics when compared to corresponding PP/EPDM blends.     

水性涂料用苯丙树脂的制备及胶膜性能

以甲基丙烯酸(MAA)为亲水单体、甲基丙烯酸羟丙酯(HPMA)为交联单体,与苯乙烯(St)、甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)等通过半连续及转相乳液聚合法,制备了具有核壳结构的水性苯丙水分散体乳液,进一步将乳液制备成苯丙树脂胶膜。探讨了MAA核壳质量比,MAA、St、HPMA等单体用量对水性苯丙树脂水分散体乳液性能及胶膜性能的影响,并利用傅里叶变换红外光谱仪(FTIR)及热失重分析仪(TGA)对苯丙树脂胶膜的结构及热稳定性进行了表征,利用激光粒径散射仪(DLS)及透射电镜(TEM)对苯丙树脂乳液乳胶粒的大小及形貌进行了表征。结果表明:当MAA在核壳中分配质量比为2∶8、MAA用量为7%(以单体总质量为基准,下同)、HPMA用量为10%、St与MMA质量比为3∶1时,得到共聚物乳液的粒径为259.65 nm,黏度为349.1 mPa?s,胶膜耐水时间为90 h,硬度为72.4?,拉伸强度为1.422 MPa,断裂伸长率为59.355%;水性苯丙水分散体附着力为1级。     

不溶液-液分散在搅拌槽内的CFD模拟

液滴平均尺寸和液滴尺寸分布是描述不溶液-液分散程度的2个重要参数,决定着两相接触面积的大小,进而决定着相间的传质、传热和化学反应速率。利用CFD方法详细研究了水-油两相在搅拌槽内的分散过程,发现叶轮转速、分散相体积分数和连续相黏度对分散效果有显著影响。当两相组成一定时,增大叶轮转速和连续相黏度均有利于两相的分散。在一定范围内,液滴平均直径与叶轮转速、分散相体积分数均为对数线性关系,相关系数高达0.999。基于个数的液滴尺寸分布在不同转速和连续相黏度条件下出现了双峰分布,而基于体积的液滴尺寸分布则始终为单峰分布。     

ABA low molar mass triblock copolymers in reverse emulsions: A rheological study

The effect of blocks length and molar mass of ABA triblock copolymers on the rheological behavior of water in oil (w/o) emulsions was investigated. Emulsion parameters such as water droplet concentration (and droplet size) of a series of inverted emulsion systems were evaluated. All copolymer/emulsion systems studied showed a non-Newtonian behavior, and the presence of the copolymer in the emulsion system led to an increase of the low shear viscosity when the size of the midblock of the copolymer was in a specific size range. This suggests the formation of a transient network through the interconnection, by the copolymer, of the smaller water droplets present in the emulsion. Consequently, the systems behave as w/o emulsions containing reversibly crosslinked oil-soluble polymers in the continuous phase, resulting in a pronounced shear thinning behavior. For the different emulsions studied, the relative viscosity increased, with few exceptions, with increasing droplet concentration. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012