RSC ChemComm Template (PC)

RSC ChemComm Template (PC) Supplementary Material (ESI) for Chemical Communications This journal is ? The Royal Society of Chemisty Supplementary information for “A novel route for preparing polyethylene/polystyrene blend through fragmentation of porous polystyrene beads supported metallocene in ethylene polymerization” Yongxin Qin, Tao Tang* and Zhongfu Zhao State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China. E-mail: ttang@ciac.jl.cn This submission was created using the RSC ChemComm Template (DO NOT DELETE THIS TEXT) (LINE INCLUDED FOR SPACING ONLY - DO NOT DELETE THIS TEXT) dried under vacuum at room temperature for 24h. The porosity Experimental Part of the support particle was confirmed by observation under transmission electron microscopy (TEM) performing on a Materials JEOL2010 microscopy operating at 200kV, as shown in Fig. 1. Styrene (St), ethyl acrylate (EA), acrylic acid (AA) and divinylbenzene (DVB) were distilled at reduced pressure under nitrogen atmosphere. Prior to use, these reagents were stored in a refrigerator. The polymerization initiator, ammonium persulfate (APS), was purified by recrystallization. Analytical grade dodecylbenzene sulfonic acid sodium salt (SDBS) and NaHCO 3were used without further purification. Toluene was dried over 4A molecular sieves for 10 days, then refluxed over Na/K alloy for at least 8h and distilled. Bis(cyclopentadienyl)zirconium dichloride (CpZrCl, Boulder Scientific Company), 22methylaluminoxane (MAO: 10 wt% in toluene, Ethyl Corporation) and ethylene (polymerization grade, Liaoyang Chemical Corporation) were used without further treatment. Fig. 1 TEM micrograph of porous support particles. Preparation of polystyrene supports The corresponding solid support particles, which were for the Emulsifier-free seeded emulsion polymerization techniques were purpose of comparison, were also prepared by emulsion used. The seeded emulsion poly (styrene-ethyl acrylate) (P(St-polymerization as above but without the alkali- and acid-EA)) was firstly prepared. A 250ml round-bottom flask was treatment. charged with 110g of water, 0.1g of SDBS, 0.24g of NaHCO, 320ml of St and 4.0ml of EA. The mixture was shaken vigorously Preparation of PS supported catalysts to form a monomer emulsion and heated up to 70? under flowing nitrogen. Then 0.24g of APS (dissolved in 10ml of MAO pretreatment of supports and reaction between CpZrCl 22water) was added to the reaction flask, and the mixture was and supports were conducted under argon atmosphere in a allowed to react for 5h. The solution was agitated throughout the specially designed flask with a magnetic stirring bar in it. About reaction by a Teflon paddle which developed a vortex in the 1.0g of support was first suspended in 20 ml of toluene with liquid. vigorous stirring. 4.0ml of MAO toluene solution was added to Then the poly (styrene-ethyl acrylate-acrylic acid- the suspended support mixture and stirred for 3h at 55?. The divinylbenzene) (PS particles) latex was synthesized as follows: liquid phase was removed and the solid was washed with 20 ml 0.1g of above seeded P(St-EA) emulsion and 90ml of water were of toluene at room temperature for four times. Then the MAO added into a 250ml four-necked flask equipped with a stirrer, a treated support was suspended again in 20 ml of toluene, 8.0ml reflux condenser and two dropping funnels. The initiator solution of catalyst toluene solution (c(Zr)=0.02 mol/L) was added and (0.54g of APS dissolved in 30ml of water) was added in one of stirred at 60? for 5h. Finally the supported catalyst was the dropping funnels and 17.0g of St, 3.0g of EA, 1.2g of AA obtained by removing the liquid phase, washed four times with and 0.3g of DVB were added in the other. When the reactor flask 20 ml of toluene per time, dried under vacuum at room was heated to 80? the initiator solution and monomer mixture temperature, and recovered as free flowing powder. The were drop-wise added to the flask within 6h. After the initiator zirconium (Zr) content of supported catalyst measured by and monomers were all added to the flask, the mixture was inductively coupled plasma atomic emission spectroscopy was allowed to continue to react for 3h. about 0.08mmol per gram of support. Finally the latex PS particles were made porous by treatment 1Preparation of polystyrene/polyethylene (PE/PS) blends stepwise with alkali and acid. About 10ml of original P(St-EA- AA) emulsion was diluted with 100ml of water in a 250ml flask, The PE/PS blends were prepared through the polymerization of and 0.1g of SDBS and 5ml of butanone were added into the flask ethylene was performed at 60? with 1.2 bar of ethylene under vigorous agitation. The mixture was adjusted to pH value pressure in a glass reactor using toluene as solvent. Before of 12.2 using 10 wt-% NaOH aq. solution and treated at 70? for polymerization, the glass reactor was heated under vacuum and 2h. After the treatment, the emulsion was rapidly cooled to room allowed to cool down under dry nitrogen flow to remove all temperature by dipping the flask in running water. Then the moisture traces. After transferring 80-150ml of toluene to the sample was adjusted to pH value of 2.2 (with 10 wt% HCl aq. reactor, a prescribed amount of MAO and supported catalyst solution) and kept at 70? for 1h. After the acid treatment, the (Al/Zr=800) were transferred to the reactor. When the reactor sample was cooled as above and adjusted to pH value of 7.0. The was heated up to the polymerization temperature, polymerization alkali- and acid-treated emulsion was dried by vaporing the was started by pressurizing the reactor with ethylene. After the solvents under an infrared lamp and the remaining powder was required reaction time, the polymerization was stopped by rapid NO TEXT BELOW THIS LINE CHEM. COMMUN., 2002, 1–XX 1 CREATED USING THE RSC CHEMCOMM TEMPLATE - SEE WWW.RSC.ORG/ELECTRONICFILES FOR DETAILS depressurization of the reactor and quenching with acidified (HCl) ethanol. The reaction mixture was precipitated in acidified ethanol over 5h, then filtered, washed with ethanol and dried in a vacuum oven overnight. By adjusting the amount of catalyst and the polymerization time, we can prepared a series of PE/PS blends with different PS content, as can be seen in Table 1. Since the supported catalyst is mostly composed of PS, the content of PS in blend was calculated by the amount of PS supported catalyst and the blend yield. Table 1 A series of PE/PS blends with different PS content produced with different amount of catalyst and polymerization time. Run Amount Polymerization Blend yield PS content no. of catalyst time (g) (min) (g) (wt%) 1 0.064 6 1.60 4 2 0.093 4 1.08 9 3 0.117 3 0.98 12 4 0.135 2 0.83 16 5 0.157 1 0.78 20 Analytical procedures The porosity of the support particle was confirmed by observation under transmission electron microscopy (TEM) performing on a JEOL2010 microscopy operating at 200kV. The phase morphological characteristics of the samples were investigated by observing the sections of the samples by means of TEM performing on a JEOL2010 microscopy operating at 200kV. Prior to the examination, cryoultrathin sections were cut using an ultramicrotome and they were stained in RuO vapor 4for 24h. The zirconium (Zr) loadings of supported catalysts were measured by inductively coupled plasma atomic emission spectroscopy (Plasma-Dec (I) of America Leeman Lab.). The surface area of support beads was measured by N sorption on a 2NOVA-1000 instrument (Quantachrome Corporation, U. S. A.). The molecular weight and molecular weight distributions of polymers were determined by high temperature gel permeation chromatography (PL-GPC 220) at 150?, using 1, 2, 4-trichlorobenzene as the eluent. The dumbbell-shape samples (thickness 0.3-0.4mm, base width 5?0.2mm, and base length 20?0.2mm) were used for mechanical tests on a universal tensile tester (Instron 1122) using a load of 20kg at room temperature. The fracture elongation and tensile strength were measured at a crosshead speed of 100mm/min. The average of five tests was reported. The thermal properties of PE/PS blends were investigated using differential scanning calorimetry (DSC, Perkin-Elmer DSC-7). Samples of about 8mg were scanned from 40? to 160? with a heating rate of 10?/min under an atmosphere of dry nitrogen. The glass transition temperature (T) gwas taken as the inflection point of the specific heat increment at the glass transition. Each blend has only one T of PE ranging in m120-140? and does not appear a glass transition temperature of PS. Further studies on the thermal and mechanical properties of the blends are now in progress and the results will be reported elsewhere. Notes and references 1 Rucjenstein, E.; Kong X. Z. J. Appl. Polym. Sci. 1999, 72, 419. NO TEXT BELOW THIS LINE 2 CHEM. COMMUN., 2002, 1–XX CREATED USING THE RSC CHEMCOMM TEMPLATE - SEE WWW.RSC.ORG/ELECTRONICFILES FOR DETAILS Single Column Figure/Scheme X Fig./Scheme XX Caption. Double Column Figure/Scheme X Fig./Scheme XX Caption. Single Column Uncaptioned Graphic/Unnumbered Equation X Double Column Uncaptioned Graphic X Numbered Equation (X) X Single Column Table Table XX Caption X a Footnote text. Double Column Table Table XX Caption X a Footnote text. NO TEXT BELOW THIS LINE CHEM. COMMUN., 2002, 1–XX 3