聚丙烯水相悬浮溶胀接枝法接枝苯乙烯

以过氧化苯甲酰(BPO)为引发剂,用水相悬浮溶胀接枝法合成了聚丙烯(PP)接枝苯乙烯(S t)的PP-g-S t接枝共聚物。考察了反应温度、反应时间、溶胀时间、苯乙烯和BPO含量对S t接枝率和接枝效率的影响。较佳的接枝反应条件为:m(S t)∶m(PP)=1、w(BPO)=0.8%、60℃溶胀90m in、反应温度85~90℃、反应时间6~7h。在较佳的接枝反应条件下,S t的接枝率可达13.2%以上。傅里叶变换红外光谱分析结果表明,S t能接枝到PP大分子主链上;示差扫描量热法分析结果表明,PP-g-S t接枝共聚物的熔点无明显变化,接枝反应主要发生在PP的无定形区。     

丙烯-苯乙烯接枝共聚物制备方法的研究进展

综述了近年来制备丙烯-苯乙烯接枝共聚物(PP-g-PS)(PP表示聚丙烯、PS表示聚苯乙烯)的研究进展。PP-g-PS的制备方法包括熔融接枝法、固相接枝法、Hivalloy合金技术、辐射接枝法、反应性单体法和大分子单体法。前3种方法得到的均是PP/PP-g-PS/PS共混物;辐射接枝法仅适用于PP的表面改性;PS大分子单体的空间位阻大,在共聚物中的含量较低;反应性单体法是一种很有工业应用前景的方法,可通过活性接枝共聚合反应,得到支链长度和接枝点密度可控的PP-g-PS。     

抗冲聚丙烯/聚对苯二甲酸乙二醇酯共混物的结构表征与抗应力发白性能的研究

采用抗冲聚丙烯(hi PP)和聚对苯二甲酸乙二醇酯(PET)为原料进行共混得到hi PP/PET共混物。利用DSC,DMA,SEM等方法分析了PET的冷结晶行为,研究了hi PP/PET共混物中各组分的相区,探讨了分散相体积收缩对共混物性能的影响。表征结果显示,hi PP/PET共混物在注塑成型过程中,PET结晶不完善,在120℃时即可完成冷结晶。hi PP/PET共混物中,橡胶、聚丙烯和PET各自具有独立的相区,橡胶和PET形成各自的独立颗粒。未经退火处理的hi PP/PET共混物的抗应力发白性能较好,共混物中的橡胶颗粒尺寸与hi PP相比有所降低,共混物中PET颗粒的收缩程度与基体差异不明显。退火之后PET颗粒的体积发生收缩,共混物中的内应力增大,聚丙烯/PET两相界面分离的趋势增加,使hi PP/PET共混物的抗应力发白性能显著降低。     

POE-g-GMA对PLA/PP共混体系结构及性能的影响

采用甲基丙烯酸缩水甘油酯(GMA)接枝乙烯-辛烯共聚物(POE)得到的POE-g-GMA作为相容剂引入到聚乳酸(PLA)/聚丙烯(PP)共混体系中,利用FTIR,DSC,SEM等方法研究了POE-g-GMA对PLA/PP共混体系性能的影响,并探讨了POE-g-GMA的增容机理.实验结果表明,POE-g-GMA改善了PL...     

技术动态

聚丙烯接枝乙烯醇结晶性能的研究因聚丙烯(PP)属非极性材料,具有较低的表面能和较低的内聚能,为此,对PP进行接枝改性,合成极性化和官能化的PP,已成为近些年来PP改性的热点。用马来酸酐(MAH)、丙烯酸(AA)、甲基丙烯酸(MMA)及其酯类等接枝PP,可有效地引入极性基团。而醋酸乙烯酯(VAc)与丙烯酸酯类比较,其毒性、刺激性和成本较低;作为接枝单体,在PP主链中引入酯基,可改善PP的印染性、吸湿性及与极性聚合物的相容性。北京化工大学教育部可控化学反应科学与技术基础重点实验室和材料科学与工程学院研究了PP、PP-g-VAc和两种不同醇解…     

降凝剂对原油中蜡非等温结晶行为的影响

以乙烯-醋酸乙烯酯共聚物(EVA)和聚丙烯酸高碳醇酯(PA)为主要原料,制备了一种高凝原油降凝剂（PA-EVA）,采用差示扫描量热法研究了降凝剂的添加对原油中蜡的非等温结晶动力学的影响。结果表明：PA-EVA降凝剂起到了异相成核作用,使蜡的结晶峰温升高,结晶速率增大;PA-EVA降凝剂通过增大蜡晶几何尺寸,减少了对液态油的包覆,从而改善原油的流动性。     

聚丙烯的自由基接枝共聚改性

论述了聚丙烯(PP)的溶液、熔融、固相及悬浮接枝改性方法,介绍了PP的接枝反应机理,还探讨了接枝反应体系中单体、引发剂、溶剂和工艺条件的选择和对接枝效率的影响。     

主链结构对聚丙烯球形粒子中苯乙烯固相接枝聚合的影响

以DQ型催化剂催化丙烯均聚和丙烯 /少量乙烯无规共聚得到的两种多细孔球形聚烯烃粒子为母体 ,进行了自由基引发苯乙烯固相接枝共聚 ,考察了反应条件对两种粒子中接枝聚合规律的影响 ,发现共聚物 (PPR )母体中的苯乙烯接枝共聚比均聚物 (PP )有更高的接枝率和接枝效率。与PP的接枝产物相比 ,具有相同接枝率的PPR接枝产物的熔点和熔融焓下降幅度较大。研究表明 ,聚丙烯的链结构对其固相接枝共聚规律和接枝产物性质有直接的影响 ,少量共聚单体的存在有利于提高接枝效率 ,并影响支链的分布     

乙烯基苯乙基聚苯乙烯大单体与丁二烯的阴离子接枝共聚合研究(Ⅰ)

用阴离子法合成了以二乙烯基苯(DVB)封端的聚苯乙烯大单体,并加以表征。首次利用阴离子法合成了此大单体与丁二烯的接枝共聚物。研究了在苯/THF、n-LiBu体系中的聚合反应特征,并用GPC、UV、IR、膜渗透等方法对共聚物进行了表征和研究。结果表明,得到的接枝丁苯共聚物的接枝数为2—22个,主链分子量3—30万,支链分子量单一控制在3000—8000内,基本实现了分子设计的目的。     

大连轻工业学院和四川大学研究预处理方法对PP固相接枝MAH的影响

近年来，对聚丙烯（PP）固相接枝正成为研究的热点。大连轻工业学院化工材料学院和四川大学高分子科学与工程学院，以聚丙烯接枝马来酸酐（PP—g—MAH）为研究对象，研究了紫外光照射法和化学溶胀法预处理对固相接枝体系的影响。结果表明，适当的紫外光照射时间和照射强度可提高PP—g—MAH的接枝率。     

PP／PET合金纤维的制备及其力学性能研究

在聚丙烯(PP)与聚苯对二甲酸乙二酯(PET)共混体系中添加增容剂PP-g-AA,用扫描电镜对共混挤出物的断面进行观察,结果发现:增容剂的加入大大改善了PP与PET两相的相容性,增容剂的最佳添加量为PET质量的50％。用PP／PET共混物制备了合金纤维,观察了纤维断面形貌,并测试了这种合金纤维的力学性能,发现PP／PET／PP-g-AA质量比为90:10:5时,合金纤维的力学性能最好。     

P(St-MAH)的合成及其对PC/PS共混体系相容性的影响

合成了不同马来酸酐含量的苯乙烯与马来酸酐共聚物Ｐ（Ｓｔ－ＭＡＨ），添加到ＰＣ／ＰＳ共混体系中，可增加二者的相容性。在共混体系中，ＰＣ相Ｔｇ变化不大，而ＰＳ相Ｔｇ升高，升高的幅度与共聚物中ＭＡＨ含量有关，含ＭＡＨ１２．８％时效果最好；也与ＰＣ／ＰＳ共混体系中ＰＳ含量有关，ＰＳ较少时升幅较大。     

PP／EPDM共混物动态硫化工艺及性能的研究

比较了不同的动态硫化工艺和硫化体系对聚丙烯（ＰＰ）／三元乙丙橡胶（ＥＰＤＭ）共混物性能的影响。结果表明，当ＥＰＤＭ加入量小于３０％时，用双螺杆挤出机构动态硫化比用双辊开炼机动态硫化效果更好。以过氧化苯甲酰（ＢＯＰ）为硫化剂，加工条件容易控制，并可得到综合性能好的ＰＰ／ＥＰＤＭ共混物。     

PP／LLDPE共混体系性能及相容性研究

使用双螺杆挤出机制备聚丙稀(PP)／线性低密度聚乙烯(LLDPE)共混物,通过GPC、DSC等手段判断了PP／LLDPE共混体系的相客性,使用常规物理机械方法测定了共混物的物理机械。结果表明:PP／LLDPE是热力学上完全不相客的体系,但是,基于结构和性质上的相似,该共混体系通过机械剪切共混可以达到一定的相客性。当PP／LLDPE=50:50-20:80时,LLDPE能明显改善PP的脆性大,同时,PP改善LLDPE的加工性、力学性能及耐热性能。     

Investigating the synergistic effect between oil soluble surfactants and styrene–maleic anhydride copolymers to enhance the flow properties of waxy crude oil

Styrene–maleic anhydride (SMA) copolymer is prepared and then reacted with octadecyl alcohol SMASA, hexadecylamine SMACA, benzyl alcohol SMABA, and aniline SMAAn to obtain four copolymers. Three oil soluble surfactants are prepared by esterification of mono-, di-, and triethanolamine with oleic acid MEAO, DEAO, and TEAO. The structure of the prepared copolymers is characterized using spectroscopic techniques such as infra-red (FTIR), ¹H nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC). The prepared copolymers are evaluated individually as flow improvers then mixed with surfactants. From the results, it is found that the copolymer with aliphatic side chain SMACA exhibited the maximum pour point depression (ΔPP = 21°C at 1,500 ppm), whereas the rest copolymers SMASA, SMABA, and SMAAn exhibited the same pour point depression ΔPP = 18°C at 1,500 ppm. Moreover, the blend (B4) between SMACA and TEAO exhibited the maximum pour point depression ΔPP = 27°C.     

几种不同分子结构柴油降凝剂的降凝效果及其复配物的协同效应

研究了几种不同分子结构柴油降凝剂的降凝效果及其复配物的协同效应。结果表明:降凝剂的成核性能以及分散性能主要取决于其分子结构,其分子结构类型对不同降凝剂复配物在柴油中的协同效应有重要影响;透射电镜(TEM)分析结果显示,乙烯-乙酸乙烯酯共聚物(EVA)的成核性能较好,甲基丙烯酸十四酯-马来酸酐-甲基丙烯酰胺三元共聚物(MC14-MA-MCNR1R2)的分散性能较强,二者复配后在柴油中具有较好的降凝点和降冷滤点效果。在该复合降凝剂作用下的石蜡晶体颗粒分散均匀,且颗粒变小,约95%的粒径为30~40 nm。借助TEM,用冷冻蚀刻法研究柴油的结晶形态以及降凝剂对柴油中石蜡晶体的作用机理是一种非常直观有效的途径。     

Performance evaluation of polymeric blend of vinyl acetate and acrylate-based copolymers in lubricating oil

Polymer modification processes like blending has attracted much attention as an easy, cost-effective and less time-consuming method for developing new polymeric materials enriched with versatile commercial application. Polymer blends are supposed to carry better thermal and mechanical properties compared to their parent polymers. In this view we have prepared a polymer blend of two copolymers– one of vinyl acetate and octyl acrylate and another of methyl methacrylate and dodecyl acrylate and characterized them by FT-IR and NMR spectroscopy. The molecular weight was determined by Gel Permeation Chromatography (GPC). We represented here a comparative study of their mechanical property as well as their performance as flow improver.     

Olive oil assessment in edible oil blends by means of ATR-FTIR and chemometrics

Oil blends containing olive oil are commonly commercialized due to economical and nutritional reasons. According to European trade standards only when an oil blend contains more than 50% (w/w) of olive oil it can be marketed with images or graphics highlighting its presence. In this work a fast method for verifying the correct labelling of such oil blends was developed. First, the capability of attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectroscopy to distinguish olive oil was tested both in pure oil samples and in blends of different oils by using a method based on partial least squares discriminant analysis (PLS-DA). 100% of the olive oils samples were correctly identified within a wide collection of pure samples of different types of vegetable oils including olive oil of different categories, varieties and origin. When studying oil blends, it was possible to differentiate between blends with olive oil content higher than 50% (w/w) and below 50% (w/w). Finally, an attempt of quantification of olive oil in blends based on PLS regression was performed. For blend samples with olive oil contents up to 50% (w/w) a prediction error of 8.28 was obtained.     

The Lubrication Properties of Binary Blends of S-4: Polyisobutene and S-4: Polyalpholephine-100

The lubrication behavior of two series of binary blends containing S-4: PAO-100 or S-4: PIB have been followed. Each series contains 5%, 10%, 15%, 20%, and 25% of PAO-100 or PIB. The results indicate that upon addition of PAO-100, viscosities, viscosity index, and flash point increase in a linear fashion. Meanwhile, pour point, TAN, and specific gravity remain constant. In the case of PIB, viscosities increase in an exponential manner, viscosity index increases then remains constant, flash point drops, and then leftovers remain constant. Other properties do not change considerably. The rheological properties of 15% and 25% blends of S-4: PAO-100 blends are similar to S-6 and S-8, respectively. Similar conditions exist for 5% and 10% of S-4: PIB blends. A motor oil which has been formulated by 15% S-4: PAO blend and a hydraulic oil which has been formulated by 5% S-4: PIB blend have shown good performance characteristics.     

Effect of ethyl acetate addition on phase stability,octane number and volatility criteria of ethanol-gasoline blends

Blending ethanol in gasoline causes problems related to volatility and phase stability of the fuel blends. Ethanol is completely miscible with water so it has high affinity to water that may be present in storage tanks or that formed due to humidity. Drop in ambient temperature influences the stability of ethanol-gasoline blends and causes phase separation to the blend. This phase separation cause disadvantages like: poor quality fuel, loss in cost, and damage to storage tanks and engine parts due to corrosion. In this work, Ethanol-blended gasolines E5, E10, E15, E20 and ethanol-free gasoline (E0) were formulated to study the effects of ethyl acetate addition on these fuels. The obtained results revealed that the addition of ethyl acetate to ethanol-gasoline blends has many advantages such as enhancing the stability of the fuel blends and improving octane number with no adverse impacts on the volatility criteria of the investigated fuel blends.