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The polymerization of norbornene has been investigated in the presence of two novel bispyrazolylimine dinickel(II) complexes bis-2-(C3HN2Me2-3,5)(C(Ph) = N(4-RC6H4)Ni2Br4 (complex 1, R = H; complex 2, R = OCH3) activated by methylaluminoxane. The two catalytic systems show high activity (up to 1.83 × 106 gPNBE/(molNi·h)) for norbornene polymerization and provide polynorbornene (PNBE) with higher molecular weights (M w = 4.44 × 105–11.57 × 105 g/mol) and narrower molecular weight distributions about 2.0. The electron-donating of methoxyl group in complex 2 could enhance the catalytic activity for norbornene polymerization, however, the molecular weights of polymers were decreased. The influences of polymerization parameters such as polymerization temperature, Al/Ni molar ratio, reaction time and catalyst concentration on catalytic activity, and molecular weight of the PNBEs were investigated in detail. The obtained PNBEs were characterized by means of 1H NMR, FTIR, and thermogravimetric analyses. The analyses results of PNBE indicated that the norbornene polymerization is vinyl-type polymerization rather than ring-opening metathesis polymerization.

Poly(butylene succinate)/bamboo fiber (BBF) biocomposites were prepared by melt blending method. Microencapsulated ammonium polyphosphate (MCAPP) was used as flame retardants to prepare flame retardant BBF biocomposites. The thermal degradation and flame retardant properties of BBF biocomposites were investigated. The volatilized products of the thermal degradation of flame retardant BBF biocomposite are saturated hydrocarbons, unsaturated alkane, CO2, carboxylic acid, acid anhydride, aromatic compounds, NH3, and CH3OH. The peak of heat release rate (pHRR) and total heat release (THR) of flame retardant BF biocomposites decrease substantially compared with that without MCAPP. The pHRR value of flame retardant BBF biocomposites decreases from 443.2 to 236.2 kW m−2 and the THR value decreases from 62.0 to 36.1 kW m−2. Furthermore, MCAPP shows the best flame retardant property at the same loading, compared with other flame retardants such as Mg(OH)2, and Al(OH)3. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

The polymerization of styrene with two pyrazolylimine nickel (II) complexes of (2-(C3HN2Me2-3, 5)(C(Ph) = N(4-R2C6H2(R1)2-2, 6)NiBr2 (Complex 1, R1 = iPr, R2 = H; Complex 2, R1 = H, R2 = NO2)) activated by methylaluminoxane was studied. The influences of polymerization parameters such as polymerization temperature, Al/Ni molar ratio, and reaction time on catalytic activity and molecular weight of the polystyrene (PS) were investigated in detail. The electron-withdrawing of nitro group in Complex 2 could not enhance the catalytic activity for styrene polymerization; however, the molecular weights of polymers were increased. Both of the two catalytic systems exhibited high activity [up to 8.45 × 105 gPS/(mol Ni h)] for styrene polymerization and provide PS with moderate to low-molecular weights (Mw = 2.21 × 104∼ 5.71 × 103 g/mol) and narrower molecular weight distributions about 2.0. The obtained PS were characterized by means of IR, 1H NMR, and 13C NMR techniques. The results indicated that the PS was atactic polymer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

A novel nanoencapsulated shape-stabilized phase change material (PCM) with stearic acid as the core and SiO2 as the shell was synthesized by a two-step procedure, in which SiO2 hollow nanospheres were prepared firstly by a template-assisted method and stearic acid was then embedded in SiO2 hollow nanospheres based on balance principle of fluid in capillary. The morphology, structure and thermal storage property of the sample were characterized by X-ray powder diffraction, scanning electron microscopy and differential scanning calorimeter. The results suggest that the as-obtained nanocapsules were regular spheres with diameters around 220 nm, and it is possible to enhance the heat transfer and repress the super-cooling phenomenon by designing the nanoencapsulated PCMs with organic PCMs as cores and inorganic materials as shells.

The polymerization of styrene with a series of bispyrazolylimine dinickel (II) complexes of bis-2-(C3HN2(R1)2-3,5)(C(R2) = N(C6H3(CH3)2-2,6)Ni2Br4 (complex 1: R1 = CH3, R2 = Ph; complex 2: R1 = CH3, R2 = 2,4,6-trimethylphenyl; complex 3: R1 = R2 = Ph; complex 4: R1 = Ph, R2 = 2,4,6-trimethylphenyl) in the presence of methylaluminoxane (MAO) was studied. The influences of polymerization parameters such as polymerization temperature, Al/Ni molar ratio, reaction time, and catalyst concentration on catalytic activity and molecular weight of the polystyrene were investigated in detail. The influence of the bulkiness of the substituents on polymerization activity was also studied. All of the four catalytic systems exhibited high activity (up to 10.50 × 105 gPS/(mol Ni h)) for styrene polymerization and provide polystyrene with moderate to low molecular weights (Mw = 4.76 × 104–0.71 × 104 g/mol) and narrower molecular weight distributions about 2. The obtained polystyrene was characterized by means of FTIR, 1H-NMR, and 13C-NMR techniques. The results indicated that the polystyrene was atactic polymer. The analysis of the end groups of polystyrene indicated that styrene polymerization with bispyrazolylimine dinickel complexes/MAO catalytic systems proceeded through a coordination mechanism. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.

The growth mechanism of multi-wall carbon nanotubes (MWCNTs) produced by pyrolyzing polypropylene composite were studied. Scanning electron microscopy, transmission electron microscopy and high resolution electron microscopy (HRTEM) were employed to demonstrate that the charred residue formed from PP/organically modified montmorillonite/nickel oxide (Ni2O3) composite contains an abundance of MWCNTs with almost homogeneous distribution of diameters. X-ray diffraction and HRTEM reveals that a real active site for the growth of MWCNTs is Ni not Ni2O3. Meanwhile, the growth mechanism described as the yarmulke mechanism is proposed based on the experimental analysis.

Two nickel(II) complexes of {2-[C3HN2(R1)2-3,5]}[C(R2) N(C6H3Pr2-2,6)]NiBr2 (complex 1: R1 = CH3, R2 = 2,4,6trimethylphenyl; complex 2: R1 = R2 = Ph) were synthesized and characterized. The solid-state structure of complex 1 has been confirmed by X-ray single-crystal analysis. Activated by methylaluminoxane (MAO), complexes 1 and 2 are capable of catalyzing the polymerization of norbornene with moderate activities [up to 10.56 × 105 gPNBE (mol Ni h)−1] with high molecular weights (Mw ≤ 13.56 × 105 g mol−1) and molecular weight distributions were around 2. The influences of polymerization parameters such as reaction temperature and Al–Ni molar ratio on catalytic activity and molecular weight of the polynorbornene were investigated in detail. The obtained polynorbornenes were characterized by means of 1H-NMR and FTIR techniques. The analytical results of polymer structures indicated that the norbornene polymerization is vinyl-type polymerization rather than ROMP. Copyright c © 2009 John Wiley & Sons, Ltd.