Bibliographic Information

XPS characterization of Friedel-Crafts cross-linked polystyrene.     Wang, Jianqi; Du, Jianxin; Yao, Hongyang; Wilkie, Charles A.    School of Chemical Engineering and Materials Science, National Laboratory of Flame Retardant Materials,  Beijing Institute of Technology,  Beijing,  Peop. Rep. China.    Polymer Degradation and Stability  (2001),  74(2),  321-326.  CODEN: PDSTDW  ISSN: 0141-3910.  Journal  written in English.    CAN 136:118831    AN 2001:773647    CAPLUS   (Copyright 2004 ACS on SciFinder (R)) 

Abstract

The combination of a difunctional alkylating agent, either hydroxymethylbenzyl chloride or a,a-dichloroxylene with polystyrene or high-impact polystyrene together with a Friedel-Crafts catalyst, 2-ethylhexyldiphenylphosphate, and an amine to react with hydrogen chloride has been studied by XPS.  The results confirm what had been suggested from previous investigations using thermogravimetric anal.; crosslinking of the polymer occurs as the temp. is raised and the alc.-contg. alkylating agent gives a greater amt. of crosslinking than does the dichloro compd.

Bibliographic Information

The application of artificial neural network (ANN) technique to formulation design of flame retardant polymers-II. halogen-free flame retardant polymeric composites.     Xia, Juntao; Wang, Jianqi; Huang, Congming.    National Laboratory of Flame Retardant Materials,  Beijing Institute of Technology,  Beijing,  Peop. Rep. China.    Journal of Fire Sciences  (2001),  19(4),  309-328.  CODEN: JFSCDV  ISSN: 0734-9041.  Journal  written in English.    CAN 136:201199    AN 2001:663352    CAPLUS   (Copyright 2004 ACS on SciFinder (R)) 

Abstract 

The application of artificial neural network (ANN) to formulation design of the natural color, halogen-free flame retardant materials was conducted by means of flame retardant expert system (FRES 2.0).  This work involves an ANN model with three objects.  The optimized outputs, such as limiting oxygen index (LOI), tensile strength (TE) and elongation (EL) were shown to be in good accordance with expts.  An intuitive graphical anal. led to dealing with the correlation between performance and components in formulations, where normally subjected to serious nonlinearity and/or multiobjects.  It should be emphasized that together with the three-layered BP (back-propagation) network-based modeling, one can do what can hardly be done before with conventional techniques.

Bibliographic Information

An XPS investigation of thermal degradation and charring of cross-linked polyisoprene and polychloroprene.     Hao, Jianwei; Wang, Jianqi; Wilkie, Charles A.    School of Chemical Engineering & Material Science Beijing Institute of Technology,  National Laboratory of Flame Retardant Materials,  Beijing,  Peop. Rep. China.    Recent Advances in Flame Retardancy of Polymeric Materials  (2000),  11  97-104.  CODEN: RAFMFH  Journal  written in English.    CAN 136:200563    AN 2001:599940    CAPLUS   (Copyright 2004 ACS on SciFinder (R)) 

Abstract

The thermal degrdn. and charring of cross-linked polyisoprene and polychloroprene (PCP) were studied using the XPS technique.  The relative intensity of carbon, the plasmon loss peak and C1s spectra, and the at. concn. of chlorine in C12p spectra was the most important in characterizing crosslinking and charring along with temp. increase.  A significant increase in plasmon loss for both PCP and PIP, particularly for PCP was detected, which indicate that crosslinking and charring reactions for PCP proceeded at an extremely high rate within narrow interval of 10° may be due to the coexistence of chlorine atom attached to carbon and double bond in the backbone.  XPS data showed that PIP cross-linked with BPO always have higher crosslinking than PCP.  PCP behaved high extent of crosslinking much stronger than that of PIP, when DCP was used.

Bibliographic Information

On the flammability of the electron-beam-induced grafting of ABS and SBS copolymers, studied by LOI/CONE/XPS.     Wang, Jianqi; Wu, Shaoli.    Beijing Institute of Technology School of Chemical Engineering & Materials Science,  National Laboratory of Flame Retardant Materials,  Beijing,  Peop. Rep. China.    Journal of Fire Sciences  (2001),  19(2),  157-172.  CODEN: JFSCDV  ISSN: 0734-9041.  Journal  written in English.    CAN 136:103054    AN 2001:419395    CAPLUS   (Copyright 2004 ACS on SciFinder (R)) 

Abstract 

Pre-irradn. of the ABS and SBS copolymers, grafting of monomers (MAA and AA) onto both copolymers (ABS/SBS-g-MAA/AA) and ion exchange of the resulted grafts with cations, such as, Na+, K+, Mg2+, Ca2+ ABS/SBS-g-MAA/AA-S(Na+), K+/Mg2+, Ca++ were involved in grafting.  A study has been made using the elevated temp. LOI and CONE in this paper focusing on appraisal of the halogen- and phosphorus-free approach imparting flame retardancy to ABS and SBS copolymers and confirmation of carbon accumulation, extent of crosslinking and onset of charring as functions of temp. by the XPS technique.  LOI technique at elevated temps. and cone calorimetry based on the oxygen consumption principle give parameters definitely assocd. with the grafting rate (Gr), such as TI,, pk-HRR, SEA, EHC, etc., for each step in grafting.  Flammability tests show that the grafting induced by electron beam has led to a large increase in LOI, e.g., ABS-MAA-S(Ca2+), + 16.5 units, TI, e.g., SBS-g-MAA-S(Mg), +42.8C; cone (25 kWm): TTI. e.g., ABS-MAA-S(Na), +28% and dramatic decreases in pk-HRR, e.g., ABS-MAA-S(Na), -67%, pk-MLR, e.g., ABS-MAA-S(Ca), -73%, SEAF, e.g., SBS-MAA-S(Ca), -65%, etc.  Most exptl. data were studied and confirmed by XPS data.

Bibliographic Information

Effect of cuprous oxide in combination with molybdenum trioxide on smoke suppression in rigid poly(vinyl chloride).     Li, Bin; Wang, Jianqi.    Department of Chemistry,  Northeast Forestry University,  Harbin,  Peop. Rep. China.    Journal of Vinyl & Additive Technology  (2001),  7(1),  37-42.  CODEN: JVATF4  ISSN: 1083-5601.  Journal  written in English.    CAN 135:108056    AN 2001:361696    CAPLUS   (Copyright 2004 ACS on SciFinder (R)) 

Abstract

Further investigation of the synergistic effect of smoke suppression between cuprous oxide and molybdenum trioxide in rigid poly(vinyl chloride) (PVC) was carried out by using a cone calorimeter (cone) at a high incident heat flux of 50 kW×m-2.  Exptl. data derived from the cone calorimeter indicated that binary mixts. of Cu2O and MoO3 clearly showed the synergistic effect in reducing smoke by decreasing total smoke prodn. (TSP), av. specific extinction area (av.-SEA), and smoke prodn. rate (SPR).  This result is in good agreement with that obtained from the NBS smoke chamber.  However, the combustion process of rigid PVC could clearly be seen from the heat release rate (HRR) curve, SPR, and fire degrdn. obtained from the cone test, which could not be detd. from the NBS smoke chamber.  It was also found that the binary mixt. showed the synergistic effect by increasing char residue and reducing the fire degrdn. of the PVC backbone at a high incident heat flux of 50 kW×m-2.  All exptl. data well supported the early crosslinking mechanism of the PVC backbone mentioned in the literature and were consistent with the fire degrdn. behavior obtained from the cone calorimeter. 

上一页  [1] [2] [3] [4] [5] [6] [7] [8]  下一页