【正文】 ole?n matrices.According to Yan et al., the addition of 1 wt % FG prior topression molding signi?cantly improves the wear resist Simultaneously with the improved wear resistance thebiopatibility of UHMWPE is not Several groups have used graphite and FG in PFT. However,most catalysts failed to produce UHMWPE. Pretreatment ofthe ?ller with cocatalyst methylaluminoxane (MAO) is one ofthe most monly used approaches for effective immobilization of metallocene and postmetallocene ,30?35Dubois successfully employed micrometersized graphite ?llersin a PFT process to produce thermoplastic PE/graphiteposites with an effective ?ller FG nanoposites with lowmolecularweight thermoplasticHDPE,37,38 LDPE,39 LLDPE,40 iPP,41 and other polymerssuch as polyaniline have been ?46 To the best of ourknowledge, there are no reports on PFT processes forproducing UHMWPE/FG nanoposites using FG nanosheets as the catalyst support.Here we report on singlesite chromium(III) constrainedgeometry catalysts immobilized on emulsi?erfree MAOimpregnated FG nanosheet dispersions in nheptane. Thisnovel catalyst generation is employed in PFT to produce newUHMWPE/FG nanoposite families. FG is pared withother nanoparticles such as MWCNT, nanometerscalemultiwall carbon 250 (C)nanotubesnanofoam NF20 1200 a bDetermined using BET N2 absorption. Determined by elementalanalysis. . = not determined.Catalyst Preparation and Ethylene Polymerization. Thecatalyst was prepared by heating the support for 2 h in vacuo at 110176。C, and the stirring speed at 1000 rpm. Polymerization was stopped byinjecting acidi?ed methanol. The polymer was ?ltered off and dried for16 h at 65 176。 SP2 這個(gè)單層雜化的碳原子排列在一個(gè)蜂窩狀格。主要的氧在溫度高于400℃的功能對(duì)應(yīng)于羥基基團(tuán)，而環(huán)氧基，羰基和羧基基團(tuán)進(jìn)行在這樣的溫度下快速熱解。據(jù)Yan et al.，之前除了1 ％（重量）的FG壓縮成形顯著提高了耐磨損性。在這里，我們對(duì)單中心鉻（III）約束幾何催化劑固定化在無(wú)乳化劑的MAO浸漬的FG納米片的分散體中的正庚烷進(jìn)行匯報(bào)。實(shí)驗(yàn)部分材料與一般注意事項(xiàng)。催化劑，二氯〔 3,4,5 三甲基1 （8 喹啉基）2 三甲基硅烷基 環(huán)戊二烯基]鉻（三） （ CR1） ，下面的程序前面報(bào)道過(guò). MAO，購(gòu)自Crompton ， Al含量為10重量％的甲苯、在干燥的氬氣氛下，存儲(chǔ)在一個(gè)手套箱（布勞恩MB 150B G II ） 。Macromoleculesheptane and TiBAl, was saturated three times with ethylene at 40 176。C, and then heated again to 200 176。C, following procedures reported byAksay and ,53 The resulting FG had an oxygencontent of wt % and a carbon content of wt %. In thesecond step, the FG was dispersed in nheptane by means ofsonication prior to adding MAO and dichloroη5[3,4,5trimethyl1(8quinolyl)2trimethylsilylcyclopentadienyl]chromium(III) (Cr1). The functional groups of FG ( mmolOH/g) predominantly consisted of hydroxyl groups, whichsupport was used to immobilize the catalyst. Polymerizationconditions: Cr1 = μmol/L。 Vheptane = 300 mL。通過(guò)元素確定分析。然后將其分散在正庚烷（ 10毫克/毫升）中，超聲處理40分鐘內(nèi)。當(dāng)使用了無(wú)機(jī)載體，溫度保持在160℃下在真空中16小時(shí)。在聚合期間，乙烯壓力保持在5巴，在40176。聚合網(wǎng)上動(dòng)力學(xué)進(jìn)行測(cè)量在一個(gè)600毫升BUCHI制高壓釜裝有機(jī)械攪拌器和軟件界面。聚被定義為超高分子量聚乙烯當(dāng)它的分子量超過(guò)106克/摩爾。所述聚合物的混合物加熱從室溫至200℃，在該溫度保持5分鐘，冷卻至70℃ ，然后再加熱到200 ℃。測(cè)量所有的納米復(fù)合材料的電阻用四點(diǎn)探針。所獲得的UHMWPE /納米復(fù)合FG樣品被壓縮成形200P熔體按（科林博士GmbH，德國(guó)） 。該對(duì)于單中心鉻固定化合成策略（Ⅲ）上的FG催化劑示于方案1中，在第一步驟中，根據(jù)悍馬制備方法FG（600米2 /克）購(gòu)自GO ，隨后通過(guò)方案1 。這氧的功能是用于產(chǎn)生FG必需的穩(wěn)定乳液，而無(wú)需添加乳化劑。與此相反， CB有一個(gè)蜂箱，樣形態(tài)類(lèi)似多孔結(jié)構(gòu)石墨，能夠吸附MAO和CR1在其孔隙中。乙烯，在40℃和5巴條件下，控制時(shí)間在22到72分鐘之間，在正庚烷中聚合，并攪拌乙烯在高溫高壓下滅菌，生產(chǎn)納米復(fù)合材料與填料。聚合填充和填充物的變化內(nèi)容進(jìn)入 填料 重量％ POL（分鐘） 活動(dòng)（克/ （毫摩爾小時(shí)） ） MW（克/摩爾） PD1 FG 43 20 000 106 2 FG 1 47 18 100 106 3 FG 34 25 400 106 4 FG 10 22 40 200 106 5 FG 10 28 27 600 106 6 CB 10 47 18 501 106 7 CNT 5 50 17 600 106 8 勃姆 5 72 11 700 106 9 石墨 5 60 14 300 106 10 NF 20 51 17 000 106 填料中的產(chǎn)品％（重量） 。之間的洗滌過(guò)程催化劑添加和添加到聚合容器是包括在內(nèi)。乙烯= 5巴。MacromoleculesArticleAl/Cr ratio did not affect catalyst adsorption because theparticle suspensions were washed with heptane to removeexcess MAO prior to Cr1 addition. Such procedures were notpossible for FG/Cr1/MAO because stable dispersions wereobtained (no sedimentation over a period of 4 h). As illustratedin Figure 2, all carbonsupported Cr1/MAO catalysts affordedUHMWPE with molar masses close to or above 10 6 g/mol.The in?uence of ?ller type and Al/Cr play an important role(cf. Table 3). The highest activities of the FG/MAO/Cr1catalyst were found at an Al/Cr molar ratio of 1500. Decreasingthis ratio decreased the catalyst activity, whereas the UHMWPEmolar mass substantially increased from 600 to 3000 kg/mol.Since it is wellknown that MAO solutions contain smallamounts of trimethylaluminum (TMA), it is very likely thatsimultaneously increasing the MAO and trimethylaluminumcontents will decrease the polyethylene molar At lowAl/Cr ratios, the catalyst activity is lower because the content ofMAO is not su?cient to scavenge catalyst poisons (.,hydroxyl groups) on the surface of FG.Very similar behavior and in?uence of the Al/Cr molar ratioon the catalyst activity were found for other carbon ?llers, suchas CNT and carbon black (cf. Figure 2 and Table 4), whereinoptimum Al/Cr molar ratios are slightly different and mostlikely depend on the type of adhesion of MAO to the support.Typical polyethylene powders and PE particle size distributionsare shown in Figure 3. The Cr1/MAO and the graphite/Cr1/MAO catalysts generate ?ne powders. Such particle distributions with high proportions of small, dustlike particles areproblematic with respect to health and safety and also makeUHMWPE unsuitable for largescal