Grafting of glycidyl methacrylate onto high‐density polyethylene with reaction time in the batch mixer

The melt grafting of glycidyl methacrylate (GMA) onto high‐density polyethylene (HDPE) in the presence of free radical initiators was investigated in the batch mixer. The graft content was determined with the titration and FTIR spectroscopy. The graft content increased with the increase of peroxide and initially introduced GMA concentration. Increase of the grafted GMA content resulted in decrease of the melt index. Interestingly, there was a sudden drop of GMA grafting content with the reaction time. It is assumed that depolymerization of GMA have taken place over the ceiling temperature. The crystallinity of the prepared glycidyl methacrylate grafted high density polyethylene (HDPE‐g‐GMA) was determined by the measurement of the heat of fusion. GMA grafted site acted as defect and crystallinity of the HDPE‐g‐GMA decreased with the increase of grafting reaction. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Sulfonation of (glycidyl methacrylate) chains grafted onto nonwoven polypropylene fabric

Sulfonation of polyglycidyl methacrylate (PGMA) chains grafted onto nonwoven polypropylene fabric is investigated in detail. Sulfonation reaction consists in implantation of sulfonate groups via epoxy ring‐opening of PGMA chains grafted onto nonwoven polypropylene fabric by reaction between the GMA‐grafted sample and sodium hydrogensulfite in water–dimethylformamide solution. On the basis of analyses of IR spectra of the appropriate samples and data of backward titration, two simultaneous processes are demonstrated to take place during the sulfonation reaction. These processes are the implantation of sulfonate groups via opening of the GMA epoxy rings and hydrolysis of the GMA epoxy rings with α‐glycol groups formation. The main peculiarities of the sulfonation reaction in depending on the GMA grafting degree are reported. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

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     

Studies on preparation of PGMA/Al2O3 and its effect on impact strength of epoxy resin

In this article, two kinds of methods for grafting polyglycidyl methacrylate (PGMA) onto Al₂O₃ surface by the radical polymerization initiated by peroxide groups and double bond groups, respectively, were investigated. In the first method, peroxide groups, as initiators, were immobilized onto the Al₂O₃ surface. Then, GMA was polymerized on Al₂O₃ under the radicals decomposed by peroxide groups, and PGMA was grafted onto Al₂O₃. But in the second method, 3‐methacryloylpropyl trimethoxysilane was chemically bonded onto the Al₂O₃ surfaces firstly to introduce double bonds. Secondly, the copolymerizations between the immobilized double bonds and the monomer GMA were performed, homopolymerizations of GMA followed, and finally PGMA was grafted to the Al₂O₃ surfaces. The effects of grafting methods on grafting degree were examined mainly. At the same time, the effects of different grafting conditions on the grafting degree were researched. Furthermore, the effect of the grafted particles PGMA/Al₂O₃ on impact strength of the epoxy composites was studied. It was found that the grafting degree achieved by the first method was much higher than that by the second, and the grafting degree can reach about 54%. Moreover, the impact strength of epoxy composites containing PGMA/Al₂O₃ particles were improved largely, and which increased with the grafting degree. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

亚临界二甲醚协助双单体固相接枝改性聚丙烯

以亚临界二甲醚为溶胀剂,偶氮二异丁腈(AIBN)为引发剂,在聚丙烯(PP)上接枝甲基丙烯酸缩水甘油酯(GMA)和苯乙烯(St),制备了接枝产物PP-g-(GMA-co-St).考察了溶胀时间、溶胀温度、反应时间、反应温度、St用量和引发剂用量对接枝产物相对接枝率和水接触角的影响.采用傅里叶变换红外光谱对接枝产物进行定量...     

Glycidyl methacrylate–grafted linear low‐density polyethylene fabrication and application for polyester/polyethylene bonding

The grafting of glycidyl methacrylate (GMA) onto linear low‐density polyethylene (LLDPE) was investigated. The grafting was performed by free‐radical grafting in the melt state in a twin‐screw extruder using an organic peroxide as initiator. The effect of initial GMA and peroxide concentration, styrene comonomer addition, as well as initial resin viscosity, on the final content in grafted moieties, unbound homopolymer, and unreacted monomer was assessed. The effect of process parameters such as flow rate, screw rotation speed, and barrel temperature was also investigated. Chemical composition was shown to be the main parameter for controlling grafting level and grafting efficiency. Grafting levels up to 1.8% and efficiency of 90% were reported even though in most conditions, the graft efficiency was severely decreased by the homopolymerization of GMA into polyGMA chains not bound to LLDPE. Finally, the effect of grafting level and the presence of unbound GMA‐based species on the efficiency GMA‐grafted LLDPE as adhesive between polyethylene and polyester were discussed. Good adhesion to poly(ethylene terephthalate) copolymer was found for low viscosity grafted polyethylene resins. A significant improvement in adhesive strength on polyester was observed when the molecular weight of the grafted LLDPE was increased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3180–3191, 2004     

Improvement of autohesive and adhesive properties of polyethylene plates by photografting with glycidyl methacrylate

Glycidyl methacrylate (GMA) was photografted with the low‐ and high‐density polyethylene (LDPE and HDPE) plates to provide their surfaces with autohesive and adhesive properties. The chemical composition and wettability of the GMA‐grafted LDPE and HDPE (LDPE‐g‐PGMA and HDPE‐g‐PGMA) plates remained constant above full coverage of the surfaces with grafted PGMA chains. Autohesive strength obtained with 1,4‐dioxane as a good solvent of PGMA increased with an increase in the grafted amount and substrate breaking was observed at the grafted amount of 117 μmol/cm². The grafted amount at substrate breaking was decreased by increasing the temperature and load during heat pressing. Adhesive strength was effectively enhanced by use of multi‐functional amine compounds because of the increase in the reaction between primary or secondary amine groups and epoxy groups appended to the grafted PGMA chains. In addition, the decrease in the amine compound concentration and the increase in the number of amino groups in the amine compounds used led to the decrease in the grafted amounts at substrate breaking. Substrate breaking occurred at lower grafted amounts for the HDPE‐g‐PGMA plates than for the LDPE‐g‐PGMA plates because the location of the photografting was restricted to the outer surface region for the HDPE plate. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 493–500, 2007     

PGMA/(Al)_2O_3制备及其对环氧树脂体系性能的影响

将带有环氧基的功能性单体甲基丙烯酸缩水甘油酯(GMA)接枝聚合在微米级氧化铝颗粒表面,制备了接枝微粒PGMA/(Al)_2O_3。考察了各种因素对接枝率的影响;利用红外光谱、扫描电镜表征了PGMA/(Al)_2O_3;并通过扫描电镜观察了PGMA/(Al)_2O_3在环氧树脂中的分散情况,初步研究了PGMA/(Al)_2O_3对环氧树脂体系的增强增韧性能。结果表明:表面引发自由基聚合反应可以成功制备复合粒子PGMA/(Al)_2O3,其接枝率随引发剂浓度和氧化铝与GMA质量比的增大先增大后减小;将PGMA/(Al)_2O_3填充到环氧密封材料中后,氧化铝颗粒在环氧树脂中分散良好,其复合材料的韧性明显高于未改性Al2O3填充的复合材料。     

Styrene‐assisted melt‐free radical grafting of glycidyl methacrylate onto isotactic poly(1‐butene)

The melt‐free radical grafting of glycidyl methacrylate (GMA) onto powered isotactic poly(1‐butene) (iPB‐1) using styrene (St) as a comonomer in a Haake mixer was studied. The effects of temperature, initial GMA, and peroxide concentration, as well as the addition of St comonomer, on the final grafting degree, grafting efficiency, and the melt flow rate of grafted polymer were studied. It was shown that the addition of St as a comonomer could significantly enhance the grafting degree of GMA on iPB‐1 and reduce the extent of degradation of iPB‐1 to some degree. It has been found that the grafting degree of dual‐monomer melt‐grafted iPB‐1 was about twice that of single‐monomer‐grafted iPB‐1 for the same monomer and peroxide concentrations. The grafting of GMA onto iPB‐1 remarkably accelerated the crystal form II → I transformation of iPB‐1. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

PP-g-GMA的制备及其改性PP/PA6合金性能

采用双螺杆熔融接枝的方法,在引发剂过氧化二异丙苯(DCP)作用下,将甲基丙烯酸缩水甘油酯(GMA)和共单体苯乙烯(St)接枝到聚丙烯(PP)上。通过傅立叶变换红外光谱仪确定了接枝物的生成,采用酸碱滴定法测定了接枝率。探讨了GMA,St,DCP不同用量对PP接枝物的接枝率和熔体流动速率的影响,并将接枝产物PP–g–(St–co–GMA)加入PP/尼龙6(PA6)的合金中,通过注塑成型样条,测定其力学性能,并观察微观结构。结果表明,St的加入能够提高接枝率,抑制副反应的发生。在PP/PA6合金中加入接枝物PP–g–(St–co–GMA),其拉伸强度可提高46.45%,弯曲强度可提高32.47%,但对冲击强度影响不大。     

Reactive grafting of glycidyl methacrylate onto polypropylene

This work explored the melt‐phase grafting of glycidyl methacrylate (GMA) onto polypropylene on a closely intermeshing corotating twin‐screw extruder (16‐mm screws, 40 : 1 length/diameter ratio). The modification of the base polypropylene to produce GMA‐grafted polypropylene was achieved via peroxide‐induced hydrogen abstraction from the polypropylene followed by the grafting of the GMA monomer or by the grafting of styrene followed by copolymerization with the GMA. In this study, both the position and order of the reactant addition were investigated as a route to improving graft yields and reducing side reactions (degradation). For the peroxide–GMA system, adding GMA to the melt before the peroxide resulted in significant improvements in the graft levels because of the improved dispersion of GMA in the melt. The addition of a comonomer (styrene) was explored as a second route to improving the graft yield. Although the addition of the comonomer led to a considerable rise in the level of grafted GMA, altering the order of the reactant addition was not found to contribute to an increase in the grafted GMA levels. However, variable levels of grafted styrene were achieved, and this may play an important role in the development of grafted polymers to suit specific needs. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

复合引发剂引发GMA熔融接枝聚1-丁烯

采用复合引发剂用Haake流变仪研究了甲基丙烯酸缩水甘油酯(GMA)-苯乙烯(St)多组分单体熔融接枝高全同聚1-丁烯(iPB)。用傅里叶变换红外光谱对接枝物进行了分析,并分别考察了复合引发剂比例、GMA用量、引发剂总用量和St用量对接枝的影响。结果表明:在复合引发剂引发下,GMA和iPB可熔融接枝,接枝率最高可达1.74%;St作为共单体可明显提高GMA的接枝率和接枝效率,当n(St)/n(GMA)为1.5时,接枝率为单独使用GMA时的2.3倍。     

接枝支链结构对聚乙烯多单体接枝共聚物结晶性能的影响

采用固相接枝法合成聚乙烯(PE)与甲基丙烯酸缩水甘油酯、苯乙烯、丙烯酸丁酯的固相接枝共聚物(PETM),利用差示扫描量热法、X射线衍射和偏光显微镜等测试手段研究了接枝支链对接枝共聚物的结晶过程的影响,并对接枝共聚物的X射线衍射峰进行分峰,计算接枝共聚物的晶胞参数。结果表明:接枝支链并没有改变PE的晶型,只是充当异相成核剂的作用并阻碍PE的晶体生长;受接枝支链影响,PE中存在不完善的结晶,PETM的结晶度比PE低。     

Preparation of iminodiacetic acid-type composite chelating material IDAA-PGMA/SiO2 and preliminary studies on adsorption behavior of heavy metal ions and rare earth ions

A kind of iminodiacetic acid (IDAA)-type composite chelating materials was prepared by first graft polymerization and subsequent polymer reaction. Monomer glycidyl methacrylate (GMA) was grafted on micron-sized silica gel particles in the manner of “graft through” in a solution polymerization system, resulting in the grafted particles poly(glycidyl methacrylate) (PGMA)/silicon dioxide (SiO₂). Subsequently, the ring-opening reaction of the epoxy groups of the grafted PGMA was carried out with IDAA as reaction reagent, resulting in the bonding of IDAA groups onto PGMA/SiO₂ and obtaining the composite chelating material IDAA-PGMA/SiO₂ particles. The effects of the main factors on the graft polymerization of GMA and the bonding reaction of IDAA were examined emphatically, and the adsorption behavior of IDAA-PGMA/SiO₂ particles toward several kinds of heavy metal ions and rare earth ions was preliminarily explored. The experiments results show that: (a) to obtain the grafted particles PGMA/SiO₂ with high grafting degree, in the graft polymerization step, the reaction temperature and the used amount of initiator should be controlled. The suitable temperature is 70°C and the appropriate used amount of initiator is 1.4 % of the monomer mass. Under the optimal conditions, the grafted degree of PGMA can reach 17.50 g/100 g. (b) It is feasible to introducing of IDAA groups onto PGMA/SiO₂ particles via ring-opening reaction of epoxy groups of the grafted PGMA under alkaline conditions, and the bonding rate of IDAA group can get up to 70% based on epoxy groups of the grafted PGMA. (c)The composite chelating material IDAA-PGMA/SiO₂ possesses very strong chelating adsorption ability for heavy metal ions, and especially toward Pb²⁺ ion, the adsorption capacity can reach 24 g/100 g. (d) The adsorption ability of IDAA-PGMA/SiO₂ for rare earth ions is weaker than that for heavy metal ions. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Radiation‐induced grafting of glycidyl methacrylate onto high‐density polyethylene (HDPE) and radiation lamination of HDPE

Radiation‐induced grafting of glycidyl meth‐acrylate (GMA) onto high‐density polyethylene (HDPE) and the radiation lamination of HDPE by bulk grafting of GMA were reported. The effects of irradiation dose, monomer concentration, and atmosphere on grafting were investigated. The extent of grafting initially increased with irradiation dose and then remained almost constant. The extent of grafting was higher in 2M GMA than in 1M GMA at the same irradiation dose. The extent of grafting in nitrogen was higher than that in air. The grafted samples were characterized with FTIR spectrometry and thermogravimetric (TG) analysis. A carbonyl group was found on grafted HDPE samples, and the carbonyl index increased with the extent of grafting. TG analyses proved the existence of grafted materials on HDPE and the grafted GMA thermally decomposes at a temperature lower than that of HDPE. Strong adhesion could be obtained with radiation lamination of HDPE by bulk grafting of GMA. Benzophenone facilitates the grafting in a proper concentration range. The adhesion mechanism of the laminated samples was the entanglement of the grafted chains. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 772–779, 2005     

RAFT‐mediated graft polymerization of glycidyl methacrylate in emulsion from polyethylene/polypropylene initiated with γ‐radiation

The successful reversible addition‐fragmentation (RAFT)‐mediated graft polymerization of glycidyl methacrylate (GMA) in emulsion phase from polyethylene/polypropylene nonwoven fabric using 4‐cyano‐4‐[(phenylcarbonothioyl)thio]pentanoic acid under γ‐irradiation at ambient condition is reported. While conventional graft polymerization in emulsion phase yielded grafted materials with low of grafting (Dg) values [<7.5% at 10% (wt/wt) GMA], addition of RAFT agent to the graft polymerization system allowed the synthesis of polyethylene/polypropylene‐g‐poly(GMA) with more tunable Dg (8% ≤ Dg ≤ 94%) by controlling the grafting parameters. Relatively good control (PDI ～1.2 for selected grafting conditions) during polymerization was attained at 100:1 monomer‐to‐RAFT agent molar ratio. The number average molecular weight of free poly(glycidyl methacrylate) (PGMA) increased as a function of monomer conversion. NMR analyses of the free PGMA homopolymers indicate the presence of dithiobenzoate group from 4‐cyano‐4‐((phenylcarbonothioyl)thio) pentanoic acid on the polymer chain. The reactive pendant oxirane group of the grafted GMA can be modified for various environmental and industrial applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45270.     

聚丙烯熔融接枝改性研究

采用熔融接枝的方法,研究了多组分体系下不同单体熔融接枝聚丙烯的性能。结果表明:在共单体苯乙烯、引发剂和聚丙烯相同的条件下,接枝物的极性均较未接枝的聚丙烯极性增加;不同单体所得接枝物的接枝率不同;熔体流动速率的降低使接枝物的加工性能有不同程度的下降。接枝物极性增加的趋势依次按接枝单体MAH、MMA、GMA递增。接枝物的偏光显微镜分析表明,接枝支链的生成可以促进聚丙烯的异相成核,使晶粒细化。     

超临界CO2协助马来酸酐对聚丙烯的接枝共聚

利用超临界流体插嵌技术协助苯乙烯和马来酸酐共单体对聚丙烯膜进行接枝改性。在制备过程中采用“两步法”,有利于研究超临界CO2的溶胀、渗透和携带作用,并且能够控制成本。临界CO2的插嵌压力、插嵌温度以及引发剂浓度是影响接枝率的主要因素。在压力10 MPa、温度42℃条件下,接枝率具有极大值,约为4.7%。对接枝前后聚丙烯膜的FT-IR、DSC、SEM表征,进一步证明了共单体确实接枝在聚丙烯膜基质上,并且随着接枝率的提高,接枝聚丙烯膜的表观结晶度和熔点均下降。     

Fuel Cell Membranes Based on Grafted and Post‐Sulfonated Glycidyl Methacrylate (GMA)

Glycidyl methacrylate (GMA) was pre‐irradiation grafted into ETFE base film of 25 μm thickness up to graft levels of 300%. The grafted films were sulfonated using a mixture of sulfite and bisulfite. FTIR and SEM–EDX analysis of the synthesized films and membranes was performed to confirm the grafting and the sulfonation. A pronounced front mechanism for grafting of GMA into ETFE was found. Regarding ex situ fuel cell relevant properties, conductivities of up to 0.25 S cm^–1 were attained. For the first time, fuel cell testing of this type of membrane is reported. These grafted membranes performed comparable to a commercial benchmark membrane (Nafion® 212) and better than a styrene‐based grafted membrane with similar conductivity. Post‐test FTIR analysis showed that a fraction of the grafted chains was lost during the test under constant current conditions, yet the membrane still exhibited superior durability compared to a styrene‐based grafted membrane. Hydrolysis of the methacrylate groups was shown not to be the principle cause of the loss of sulfonic acid groups.     

PGMA／Al2O3填充环氧树脂灌封材料性能的研究

采用“Grafting from”的方法,制备了接枝微粒聚甲基丙烯酸缩水甘油酯／Al2O3（PGMA／Al2O3）。研究了PGMA/Al2O3及固化剂用量对环氧灌封材料的性能影响。利用扫描电镜观察了PGMA/Al2O3填充的环氧灌封材料的冲击断面的形貌。结果表明,对氧化铝粒子进行接枝改性后,复合粒子在环氧树脂灌封中得到良好的分散、增韧效果明显优于未改性的Al2O3,且在用量较少时就可明显提高环氧灌封材料的冲击强度。