长链不饱和脂肪酸接枝聚丙烯

系统地研究了长链不饱和脂肪酸 (十一烯酸 )熔融接枝聚丙烯 (PP) ,探讨了加工条件、引发剂类型与浓度、单体浓度等因素对接枝反应的影响 ,并将结果与短链羧酸丙烯酸 (AA)在PP上的接枝进行比较 ,考察链长因素对接枝的影响。结果表明 ,在DCP、BPO的双重引发下 ,十一烯酸在PP上的熔融接枝是成功的。反应条件对接枝率有一定的影响。和短链羧酸丙烯酸在PP上的接枝相比 ,相同接枝条件下十一烯酸的接枝率较低。DSC测试结果表明 ,十一烯酸接枝前后和丙烯酸接枝前后PP的结晶性能有不同的变化趋势。     

油酸熔融接枝聚丙烯的研究

系统地研究了油酸这一长链不饱和脂肪酸熔融接枝聚丙烯（ＰＰ）,探讨了反应条件（如转速、反应温度、反应时间）、引发剂类型及浓度、单体浓度、加入第２单体（苯乙烯）等因素对接枝反应的影响。采用红外光谱表征了ＰＰ接枝产物,并用差示扫描量热法研究了接枝前后ＰＰ结晶性能的变化。     

Grafting of long‐chain unsaturated carboxylic acids onto acrylonitrile–butadiene–styrene terpolymer

The graft copolymerization of undecylenic acid, oleic acid, and crotonic acid onto acrylonitrile–butadiene–styrene terpolymer (ABS) was initiated by benzoyl peroxide (BPO) in 1,2‐dichloroethane solution. The infrared spectra confirmed that undecylenic acid, oleic acid, and crotonic acid were successfully grafted onto the ABS backbone. The grafting occurred at the butadiene region of the ABS. The grafting degree increased with increasing monomer concentration, but it decreased after monomer concentration, reaching 0.30 mol/L in undecylenic acid and oleic acid systems. The grafting degree increased rapidly with increasing initiator concentration, but slowed down at about 0.012 mol/L of initiator concentration. The grafting degree decreased considerably with increasing ABS concentration; however, the total amount of grafted monomer increased. Increasing reaction time and temperature led to an increase in grafting degree. The chain length of the monomer has a great influence on grafting. The grafting degree decreases with increasing the chain length due to a steric hindrance and monomer cage effect, which is in agreement with activation energy calculation. The overall activation energy of crotonic acid, undecylenic acid, and oleic acid systems are 118, 122, and 134 kJ/mol, respectively. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1934–1939, 2002     

Study on the Graft Reaction of Poly(propylene) Fiber with Acrylic Acid

Summary: In this paper, the graft of poly(propylene) fiber with acrylic acid is investigated. The effects of grafting temperature, monomer concentration, and grafting time on the grafting degree of acrylic acid onto poly(propylene) fiber are discussed. In contrast to the conventional method of determining the grafting degree gravimetrically, the acid‐base titration method used in this paper was more efficient, even at low grafting degree. High‐performance liquid chromatography (HPLC) was used to estimate the averaged length of the grafted poly(acrylic acid) chains on each grafted site of poly(propylene) backbone. And also a mechanism for the grafting polymerization is proposed.

Possible microstructures of two PP‐g‐AA samples at the same grafting degree.     

Graft polymerization of N‐tert‐butylacrylamide onto polypropylene during melt extrusion and biocidal properties of its products

Functionalization of polypropylene (PP) by radical graft polymerization with N‐tert‐butylacrylamide (NTBA) was successfully conducted during melt extrusion, and the grafted products were employed as precursors of biocidal N‐halamine polymers. Graft polymerization conditions, including monomer and initiator concentrations, addition of a comonomer styrene (St), were studied. Fourier transformed spectroscopy (FTIR) results and nitrogen analysis confirmed the graft polymerization on PP backbone during the reactive extrusion. The results also indicated that increase in initiator concentration led to more PP chain scission and reduction in mixing torque or polymer chain length. As the monomer concentration rose, grafted monomer content in the products improved, revealing increased grafting copolymerization in the system. Addition of St as a comonomer adversely affected grafting of NTBA, but significantly prevented polymer chain scission. This may be due to lower tendency of NTBA for copolymerization. The halogenated products exhibited potent antimicrobial properties against Escherichia coli, and the antimicrobial properties were durable and regenerable. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers     

PP-g-(AA-AM)的制备与结构性能表征

利用电子束预辐照粉末聚丙烯,水溶液中引发丙烯酸(AA)和丙烯酰胺(AM)接枝共聚合,制备了PP-g-(AA-AM)接枝共聚物。研究预辐照剂量、反应时间、单体比例与浓度对接枝率的影响,用FTIR和接触角测量仪分析其结构和表面性能。结果表明:辐照剂量为5kGy,反应时间为3h,AM/AA单体比例为(60/40～0/100),AM单体浓度为(3～5mol·L-1),AA(2～3mol·L-1)时,接枝率较高;FTIR结果证明,AA和AM均已接枝到聚丙烯中,并随接枝率增加相应峰面积增大,对水接触角(WCA)减小,亲水性明显改善。     

超临界CO2中PP与MAA的接枝反应

利用超临界CO2作为甲基丙烯酸（MAA）的溶剂和聚丙烯（PP）的溶胀剂，合成了MAA与PP的接枝聚合物（PP-g-MAA）。考察了单体浓度、引发剂用量、反应压力、反应时间等反应条件对接枝率的影响。结果表明：在合适的反应条件下，MAA的接枝率最高可达14．6％，而且接枝后PP颗粒的外观可以保持不变。用FT-IR、DSC以及SEM等方法对样品进行了表征。DSC曲线发现PP-g-MAA有两个熔融峰。SEM观察发现PP-g-MAA的表面比PP表面明显粗糙。     

Radiation synthesis of polypropylene-acrylate grafted fiber and its remediation in the spillage of water-insoluble organic chemicals

A new kind of functionalized polypropylene(PP)-acrylate grafted fiber were prepared by radiation-induced graft polymerization of methyl acrylate (MA), ethyl acrylate(EA) and butyl acrylate (BA) monomer onto the PP fiber matrix, as a recovery adsorbent for insoluble organic chemicals. The grafting conditions of monomer concentration and irradiation time on the grafting degree were optimized. The obtained grafted fiber sample was identified by Fourier transform infrared (FT-IR) spectrometer and scanning electron microscopy (SEM) to characterize the chemical and morphological changes of the polypropylene fiber surface. The adsorption results indicated that the grafted fiber could be used to remove organic chemicals from water surface. The adsorption capacity of grafted fiber with different acrylate monomer was obviously different for the same chemicals, therefore, investigations with respect to organic removal, dynamic oil retention, and reusability, the effect of monomer polarity on the adsorption capacity of grafted fiber was especially highlighted in this study.     

pH Sensitive polypropylene porous membrane prepared by grafting acrylic acid in supercritical carbon dioxide

pH sensitive membrane was prepared by grafting acrylic acid (AA) on the porous polypropylene (PP) membrane using supercritical (SC) CO₂ as a solvent. The monomer (AA) and the initiator (benzyl peroxide, BPO) were impregnated into the PP substrate with the aid of SC CO₂, and were grafted onto the microporous PP substrate. The grafted membranes were characterized by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), and the water permeability of the virgin and grafted membranes were determined at different pH values. It was demonstrated that the grafting degree (Dg) could be easily controlled by varying operating conditions, such as the monomer concentration, pressure, and temperature during the soaking process. The water permeation of the virgin membrane is nearly independent of pH. However, the water permeation of grafted membranes decreases dramatically with pH as the pH varies from 3 to 6 because the conformation of the PAA changes significantly with the pH of the contacting solution.     

Radiation grafting of hydrophilic monomers onto poly(4-methylpentene-1), II. Grafting of long chain monomers and physical properties of the grafted films

Radiation grafting of 2-hydroxyethyl methacrylate (HEMA) and methoxytetraethyleneglycol methacrylate (M4G) on low crystallinity poly(4-methylpentene-1) (TPX) has been investigated. Grafting yield increased with increasing pre-irradiation dose, grafting temperature, and monomer concentration. Grafting rate depends on length of molecular chain in the monomers and decreases with increasing chain length. The grafting yields of electron beam irradiated samples were higher than those of γ-irradiated ones because of higher radical concentration. Tensile strength of the grafted film in the dried state increased and the elongation at break decreased with increasing degree of grafting. On the other hand, in the wet state, the tensile strength and elongation at break decreased with increasing the degree of grafting due to the lack of hydrogen bonds between the grafted chains caused by increased water absorption.     

Melt grafting of maleic anhydride onto polypropylene with 1‐decene as a second monomer

The influence of 1‐decene as the second monomer on the melt‐grafting behavior of maleic anhydride (MAH) onto polypropylene (PP) was studied with differential scanning calorimetry and Fourier transform infrared spectroscopy. We found that the value of the grafting degree increased from 0.68% for pure MAH‐g‐PP to 1.43% for the system with a 1‐decene/MAH molar ratio of 0.3, whereas the maximum value with styrene (St) as the second monomer was 0.98% under an St/MAH molar ratio of 1.0. Compared with the contribution of St/MAH‐g‐PP to the peeling strength between the PP and polyamide (PA) layer for a PP/PA laminated film, the introduction of 1‐decene/MAH‐g‐PP increased the peeling strength from 180 g/15 mm to 250 g/15 mm. 1‐Decene inhibited the chain scission behavior of PP. 1‐Decene reacted with MAH to form a 1‐decene/MAH copolymer or the Alder‐ene reaction product before the two monomers grafted onto PP. The grafting of the reactive product onto PP greatly improved the grafting degree of MAH. What is more, because of the similar chemical structures of 1‐decene and PP, the affinity of 1‐decene with PP was higher than that of St. Compared with St, the introduction of less 1‐decene led to a higher grafting degree and higher peeling strength. Therefore, we concluded that 1‐decene was more effective for improving the grafting degree of MAH onto PP. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Study of multi‐monomer melt‐grafting onto polypropylene in an extruder

Free‐radical melt‐grafting of the dual‐monomer systems glycidyl methacrylate–styrene (GMA‐St) and hydroxyethyl methacrylate–styrene (HEMA‐St) onto polypropylene (PP) has been studied using a single‐screw extruder. For single monomer grafting systems, degradation of PP was unavoidable and deterioration of the mechanical properties of the grafted PP subsequently occurred because of β‐scission of PP chains during the free‐radical melt‐grafting process. However, for the dual‐monomer systems, it is shown that the addition of styrene as a comonomer can significantly enhance the GMA or HEMA grafting levels on PP and reduce the extent of β‐scission of PP backbone. It has been found that the grafting degree of dual‐monomer melt‐grafted PP, such as PP‐g‐(GMA‐co‐St) or PP‐g‐(HEMA‐co‐St), is about quadruple that of single‐monomer grafted PP for the same monomer and dicumyl peroxide concentrations. Moreover, the melt flow rate of the dual‐monomer grafted PP is smaller than that of the unmodified PP. Hence, PP not only was endowed with higher polarity, but also kept its good mechanical properties. © 2000 Society of Chemical Industry     

等离子体引发聚合固定金属离子亲和膜的制备及其吸附性能

引　言亲和膜分离技术综合了亲和色谱选择性高和膜过程简单、连续、易放大的特点 ,近 10年来对这类膜及其过程的研究在生化分离领域成为热点[1～ 3] .在亲和膜制备过程中 ,膜的活化大都是通过化学反应来实现的 ,工艺复杂 ,费时费力 .而等离子体引发聚合法可以直接将所需基团接枝到膜上 ,省略膜的活化过程 ,与传统的方法相比具有工艺简单、操作方便、基膜和接枝单体的选择范围广等优点 .等离子体引发聚合在膜分离领域的应用主要集中在渗透汽化膜材料的改性和制备[4 ] 、固定化酶膜的制备[5] ,而在亲和膜的制备方面报道较少 .Ｋｉｙｏｈａｒａ…     

Preparation of hydrophilic membranes by grafting acrylic acid onto pre-irradiated teflon-FEP films

Grafting of acrylic acid onto pre-irradiated poly(tetrafluoroethylene-hexafluoropropylene) (Teflon-FEP) films was investigated, and the reaction parameters dose, dose rate, monomer concentration and grafting temperature were examined. The results show that the degree of grafting depends on the dose (5-60 kGy), the weight of grafted specimen increased up to 37%. The degree of grafting was found to be independent of the dose rate. The overall activation energies were calculated to be 28.8 and 81.6 kJ mol^-1 for treatments at above and below 50°C, respectively. The swelling of grafted films was measured in water, aqueous potassium hydroxide and methanol. The degree of swelling was found to increase with the length of grafted chains.     

Supercritical CO2 assisted ternary-monomer grafting copolymerization of polypropylene

Free-radical grafting of ternary-monomer onto polypropylene (PP) particles in the solid state has been studied using supercritical carbon dioxide (SC CO₂) as a solvent and a swelling agent. The PP particles were first swelled with the monomers and AIBN as an initiator, using SC CO₂ at different experimental conditions of pressure, temperature and treatment time. After releasing CO₂, monomers were grafted onto PP in different temperatures. During monomer selection, combination of soft monomer and hard monomer was used in order to tune polarity and flexibility of grafted polymer. FTIR spectra confirmed that ternary-monomer had been grafted onto PP and SEM showed that grafted molecules had been uniformly distributed in the PP substrate. TG analysis indicated that thermal stability of grafting modified PP had been improved, and DSC revealed that grafting leads to a lower degree of crystallinity of polypropylene.     

Influence of grafting formulations and extrusion conditions on properties of silane‐grafted polypropylenes

The melt grafting of unsaturated silanes onto powdered polypropylene (PP) in a Haake TW100 twin‐screw extruder and curing in hot water were studied. The influence of grafting formulations and extrusion conditions on the melt flow rates of grafted PP and the gel percentages of crosslinked PP was investigated. The gel percentages of methacryloylpropyltrimethoxysilane (VMMS)‐grafted PP were markedly higher than those of vinyltriethoxysilane (VTES)‐ and vinyltrimethoxysilane (VTMS)‐grafted PP, while significantly less degradation of PP during grafting was observed for VMMS‐grafted PP. When benzoyl peroxide (BPO) was used as an initiator, no degradation of PP during grafting was observed, and the melt flow rates of grafted PP decreased with increasing BPO concentration. In contrast, use of dicumyl peroxide (DCP) as an initiator resulted in severe degradation of PP, and the melt flow rates of grafted PP increased gradually with increasing DCP concentration. BPO resulted in higher gel percentages than those of DCP at a fixed initiator concentration. Introduction of styrene into the grafting system greatly improved the gel percentage of crosslinked PP and reduced the degradation of PP during grafting. The optimum molar ratio of styrene to monomer is at about 1.5:1. Relatively low processing temperatures and high screw speeds are favorable. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1233–1238, 2000     

Radiation‐induced grafting of pentamethyl hindered amine light stabilizer 1,2,2,6,6‐pentamethyl‐4‐piperidinyl methacrylate onto polypropylene

The γ‐radiation‐induced grafting of 1,2,2,6,6‐pentamethyl‐4‐piperidinyl methacrylate (PMPM) onto polypropylene (PP) was investigated with a simultaneous irradiation technique. The effects of the solvent, dose, monomer concentration, and photoinitiator on the grafting were investigated. The grafting was easier in a benzene solution than in chloroform and acetone solutions. The grafting percentage first increased almost linearly with the irradiation dose until 20 kGy and then increased slowly or remained constant. The grafting percentage increased with the monomer concentration until 1.1 mol/L. The grafting percentage was higher when the proper amount of benzophenone was added. The grafted samples were characterized with Fourier transform infrared spectroscopy and thermogravimetric analysis. Carbonyl groups were found on grafted PP samples, and the carbonyl index increased with the grafting percentage. Thermogravimetric analyses proved the existence of grafted materials on PP, and grafted PMPM thermally decomposed at a lower temperature than PP. The radiation resistance of PP with grafted PMPM was better than that of pristine PP. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2157–2164, 2005     

Surface modification of polypropylene microporous membrane by grafting acrylic acid using physisorbed initiators method

Surface modification of microporous polypropylene (PP) membrane was performed by graft polymerization of acrylic acid using physisorbed initiators method. The factors effecting on the grafting degree such as monomer concentration, reaction temperature and initiator density were determined. The morphological and microstructure changes of the membrane were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and Fourier transform infrared spectroscopy (FTIR). The pure water contact angle, protein adsorbed amount, water flux, and antifouling property of the grafted membrane were investigated. The results indicated that the pore size and porosity of the grafted membrane were reduced and the static contact angle of pure water on the grafted membrane decreased from 108° to 40° with the increase of grafting degree. The amount of protein adsorbed on the grafted membrane decreased about 30% compared to the virgin polypropylene membrane when the grafting degree was 18.71%. Though the water flux reduced, the flux recovery of the grafted membrane increased 82.66% with the grafting degree 16.0%. The hydrophilic and antifouling property of the grafted membrane also were improved. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The study on radiation grafting of acrylic acid onto fluorine-containing polymers. IV. Properties of membrane obtained by preirradiation grafting onto poly(tetrafluoroethylene–hexafluoropropylene)

Some properties of the membranes obtained by preirradiation grafting of acrylic acid onto poly(tetrafluoroethylene–hexafluoropropylene) (FEP) film have been investigated. Swelling behavior, dimensional change by grafting, electric conductivity, and mechanical properties of the grafted films were found to depend largely on the degree of grafting and to increase as the grafting proceeds. These properties were also found to be independent of the preparation conditions such as irradiation dose, grafting temperature, film thickness, and monomer concentration lower than 60 wt %. The electric conductivity of the membranes prepared at lower monomer concentration (lower than 60 wt %) is higher than that prepared at 80 wt % acrylic acid concentration. X-ray microscopy of the grafted film revealed that the grafting proceeds from both surfaces of the film to the direction of center to give finally homogeneous grafting through the whole bulk of film. At lower monomer concentration the homogeneous grafting was achieved at a degree of grafting around 18%, while at 80 wt % acrylic acid it was achieved at a degree of grafting higher than 70%. The homogeneously grafted membranes show good electrochemical and mechanical properties which make them acceptable for practical uses as cation-exchange membranes.     

Fouling control in a submerged membrane‐bioreactor by the membrane surface modification

To improve the antifouling characteristics, polypropylene microporous membranes (PPHFMMs) were surface‐modified by the sequential photoinduced graft polymerization of acrylic acid and acrylamide. The grafting density and the grafting chain length, which played important roles in the antifouling characteristics, were controlled in the first and the second step, respectively. The ATR/FTIR results clearly indicated the successful modification on the membrane surface. The static water contact angle of the modified membrane reduced obviously with the increase of the grafting chain length. The contact angle of the acrylic acid modified membranes was lower than that of the acrylamide modified membrane with similar grafting chain length. The grafting chain length increased with the increase of UV irradiation time and monomer concentration. The grafting chain length of poly(acrylic acid) (PAAc) was lower than that of the polyacrylamide (PAAm) under the same polymerization conditions. Pure water flux for the modified membranes increased with the increase of grafting chain length, and had maximums. The antifouling characteristics of the modified membranes in a submerged membrane‐bioreactor (SMBR) were evaluated. The modified membranes showed better filtration performances in the SMBR than the unmodified membrane, and the acrylic acid grafted membrane presented better antifouling characteristics than acrylamide modified membranes. The results demonstrated that the surface carboxyl‐containing membranes were better than the surface amido‐containing membranes. The results of Pearson correlations demonstrated that the PAAc modified membranes with longer grafting chain length had higher flux recoveries, while the PAAm modified membranes with longer grafting chain length had lower flux recoveries. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010