聚亚苯基硅氧烷交联网络的热性能

用Si—H/Si—OR缩聚的方法制备了含可交联乙烯基的聚亚苯基硅氧烷-二甲基硅氧烷共聚物(PTMPS-DMS),用硅氢加成、BPO热交联两种方法进行交联得到交联网络,并用热重分析(TG)、300℃恒温热分析和DSC等方法对其热性能进行了研究。结果表明,交联方法对PTMPS-DMS交联网络的热稳定性影响很大,BPO热交联网络的热稳定性远远高于硅氢加成交联网络,两种交联网络在空气中的5%热失重温度分别是480℃和368℃,Tg则没有显著差异,分别是-55℃和-49℃。H2PtCl6能显著降低PTMPS-DMS及其交联网络在空气中的热稳定性。     

聚甲基乙烯基硅氧烷增韧聚苯硫醚的力学性能研究

通过熔融共混制备了聚苯硫醚/无苯基聚甲基乙烯基硅氧烷(PPS/NPMVS)共混物及聚苯硫醚/单苯基聚甲基乙烯基硅氧烷(PPS/SPMVS)共混物,并对该共混物体系的微观形貌及力学性能进行了分析表征。结果表明,弹性体在共混物中均匀分散,弹性体的加入对PPS基体起到明显的增韧效果;当弹性体的含量为3 %（质量分数,下同）时,2种共混材料的增韧性能最佳,PPS/NPMVS共混材料的断裂伸长率相对于PPS基体提高了3.9倍,PPS/SPMVS共混材料的断裂伸长率相对于PPS基体提高了2.4倍;当NPMVS含量为10 %时,PPS/NPMVS共混材料的冲击强度相对于PPS基体提高了1.8倍,当SPMVS含量为3 %时,PPS/SPMVS共混材料的冲击强度相对于PPS基体提高了1.4倍。     

Synthesis and characterization of poly(dimethyl siloxane) containing poly(vinyl pyrrolidinone) block copolymers

ABA‐type block copolymers containing segments of poly(dimethyl siloxane) and poly(vinyl pyrrolidinone) were synthesized. Dihydroxyl‐terminated poly(dimethyl siloxane) was reacted with isophorone diisocyanate and then with t‐butyl hydroperoxide to obtain macroinitiators having siloxane units. The peroxidic diradical macroinitiators were used to polymerize vinyl pyrrolidinone monomer to synthesize ABA‐type block copolymers. By use of physicochemical methods, the structure was confirmed, and its characterization was accomplished. Mechanical and thermal characterizations of copolymers were made by stress–strain tests and differential scanning calorimetric measurements. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1915–1922, 1999     

Poly(para‐dioxanone) and poly(L‐lactic acid) blends: thermal,mechanical, and morphological properties

Blends of two semicrystalline polymers, poly(L ‐lactic acid) (PLLA) and poly‐p‐dioxanone (PPD) have been prepared by solvent casting in different compositions. Thermal, morphological, and mechanical properties of the blends were studied using modulated differential scanning calorimetry, wide‐angle X‐ray diffractometry, scanning electron microscopy (SEM), polarizing light microscopy (PLM), and tensile tests. Thermal analysis showed two glass transition temperatures nearly constant and equal to the values of the homopolymers and constant values of melting temperature (T_m) for all blend compositions, suggesting that both polymers are immiscible. The PLM and SEM observations validated these results, and showed the different morphology obtained by changing the composition of the blend. The blends 40/60, 50/50, and 60/40 presented a clearly macroseparated system, while the 20/80 and 80/20 blends presented better homogeneity, probably due to the low amount of one component in the other. It was found by PLM that PPD is able to crystallize according to a spherulitic morphology when its content is above 40%. Under this content, the crystallization of PPD is hardly observed. The blend 20/80 is more flexible, and tough material and neck formation during elongation is also observed, due to PPD, which may act as a plasticizer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 12: 2744–2755, 2003     

The effect of segment length on some properties of thermoplastic poly(ester–siloxane)s

A series of novel thermoplastic elastomers, based on poly(dimethylsiloxane) (PDMS) as the soft segment and poly(butylene terephthalate) (PBT) as the hard segment, were synthesized by catalyzed two‐step, melt transesterification reactions of dimethyl terephthalate and methyl esters of carboxypropyl‐terminated poly(dimethylsiloxane)s (M?_n = 550–2170 g mol^?1) with 1,4‐butanediol. The lengths of both the hard and soft segments were varied while the weight ratio of the hard to soft segments in the reaction mixture was maintained constant (57/43). The molecular structure, composition and molecular weights of the poly(ester–siloxane)s were examined by ¹H NMR spectroscopy. The effectiveness of the incorporation of the methyl‐ester‐terminated poly(dimethylsiloxane)s into the copolymer chains was verified by chloroform extraction. The effect of the segment length on the transition temperatures (T_m and T_g) and the thermal and thermo‐oxidative degradation stability, as well as the degree of crystallinity and hardness properties of the synthesized TPESs, were studied. Copyright © 2003 Society of Chemical Industry     

Synthesis and characterization of thermoplastic poly(ester–siloxane)s

Two series of thermoplastic poly(ester–siloxane)s, based on poly(dimethylsiloxane) (PDMS) as the soft segment and poly(butylene terephthalate) as the hard segment, were synthesized by two‐step catalyzed transesterification reactions in the melt. Incorporation of soft poly(dimethylsiloxane) segments into the copolyester backbone was accomplished in two different ways. The first series was prepared based on dimethyl terephthalate, 1,4‐butanediol and silanol‐terminated poly(dimethylsiloxane) (PDMS‐OH). For the second series, the PDMS‐OH was replaced by methyl diesters of carboxypropyl‐terminated poly(dimethylsiloxane)s. The syntheses were optimized in terms of both the concentration of catalyst, tetra‐n‐butyl‐titanate (Ti(OBu)₄), and stabilizer, N,N′‐diphenyl‐p‐phenylene‐diamine, as well as the reaction time. The reactions were followed by measuring the inherent viscosities of the reaction mixture. The molecular structures of the synthesized poly(ester–siloxane)s were verified by ¹H NMR spectroscopy, while their thermal properties were investigated using differential scanning calorimetry. © 2001 Society of Chemical Industry     

二甲基苯基硅氧基封端聚(二甲基-甲基苯基)硅氧烷共聚物的热分解性能及动力学研究

以1,1,3,3-四甲基二苯基二硅氧烷为封端剂,八甲基环四硅氧烷与甲基苯基环硅氧烷混合物为共聚单体,在阴离子催化剂作用下合成了二甲基苯基硅氧基封端的聚(二甲基-甲基苯基)硅氧烷共聚物。采用非等温TG技术,在惰性气氛和5.0、10.0、15.0和40.0 K min 1线性升温速率条件下,考察了共聚物非等温热降解机理及反应动力学,采用Friedman-Reich-Levi、Flynn-Wall-Ozawa和Kissinger等方法对非等温动力学数据进行分析,所得平均表观活化能分别为113.64、115.69和145.80 kJ mol 1。采用等转化率法确定出共聚物热分解反应符合Avrami-Erofeev方程,反应机理为随机成核和随后生长。采用Crane和Doyle方法研究了不同升温速率对反应级数、活化能和指前因子的影响,结果表明降解反应为一级反应,反应活化能介于152.46~183.13 kJ mol 1之间,指前因子介于4.25×109~4.02×109s 1。同时采用等温TG技术得到失重5%和10%条件下的寿命方程,对共聚物的寿命进行了预测。     

New Poly(azomethine‐urethane)s including melamine derivatives in the main chain: Synthesis and thermal characterization

Up to date, only a few kinds of poly (azomethine‐urethane)s (PAMUs) derived from aromatic hydroxy compounds were obtained and studied with thermal degradation steps. Novel PAMUs were prepared using the hydroxy‐functionalized Schiff bases derived from melamine and toluene‐2,4‐diisocyanate. Schiff base prepolymers were synthesized by the condensation reaction of melamine with 4‐hydroxybenzaldehyde and 2‐hydroxy‐1‐naphtaldehyde. Characterization was made by UV–Vis, FTIR, NMR, and SEC techniques. Thermal characterizations of the novel PAMUs were carried out by TG‐DTA and DSC techniques. Thermal decomposition steps at various temperatures were also clarified and the physical changes of the synthesized PAMUs with exposing to the thermal degradation steps were displayed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of silphenylenesiloxane units on the thermal stability of poly[methyl(trifluoropropyl)siloxane]

A series of poly[methyl(trifluoropropyl)siloxane-co-silphenylenesiloxane] (PMTFPS-co-SPS) was synthesized by condensation polymerization of methyltrifluoro-propylsiloxanediol and 1,4-bis(dimethylsilyl)benzene. Their chemical structures were investigated using gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and dynamic thermomechanical analysis (DMA). The effect of silphenylenesiloxane (SPS) units on the thermal stability of poly[methyl(trifluoropropyl)siloxane] (PMTFPS) was studied by thermogravimetric analysis (TGA), isothermal degradation tests, quantum chemical calculation, and pyrolysis-gas chromatography–mass spectrometry (Py-GCMS). The results showed that the thermal stability of PMTFPS improved with the introduction of SPS units into the backbone. The temperature for 5% mass loss in PMTFPS increased by 63°C under a nitrogen atmosphere. Additionally, the mechanism by which the SPS units improve the thermal stability of PMTFPS was also investigated.     

Fabrication and characterization of TiO2/poly(dimethyl siloxane) composite fibers with thermal and mechanical stability

The mechanical stability of titania (TiO₂) nanofibers was improved by fabricating TiO₂/poly(dimethyl siloxane) (PDMS) composite fibers using a combination of hybrid electrospinning and sol‐gel methods, followed by heat treatment at 250°C for 3 h. The compositions (90/10, 80/20, and 70/30, w/w) of the TiO₂/PDMS composite fibers were varied by adjusting the flow rate of the PDMS sol with the flow rate of TiO₂ sol fixed. There was no significant change in morphology and average diameter of the as‐spun TiO₂/PDMS fibers after heat treatment. Both the tensile strength and modulus of the TiO₂/PDMS composite fibers increased gradually with increasing PDMS content up to 30 wt %. In addition, from the photo‐degradation reaction of methylene blue, the photocatalytic activity of TiO₂/PDMS composite fibers was strongly dependent on the TiO₂ content (%) in the composite fibers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of poly(ester ether siloxane)s

A series of novel thermoplastic elastomers based on ABA‐type triblock prepolymers, poly[(propylene oxide)–(dimethylsiloxane)–(propylene oxide)] (PPO‐PDMS‐PPO), as the soft segments, and poly(butylene terephthalate) (PBT), as the hard segments, was synthesized by catalyzed two‐step melt transesterification of dimethyl terephthalate (DMT) with 1,4‐butanediol (BD) and α,ω‐dihydroxy‐(PPO‐PDMS‐PPO) (M?_n = 2930 g mol^?1). Several copolymers with a content of hard PBT segments between 40 and 60 mass% and a constant length of the soft PPO‐PDMS‐PPO segments were prepared. The siloxane‐containing triblock prepolymer with hydrophilic terminal PPO blocks was used to improve the compatibility between the polar comonomers, i.e. DMT and BD, and the non‐polar PDMS segments. The structure and composition of the copolymers were examined using ¹H NMR spectroscopy, while the effectiveness of the incorporation of α,ω‐dihydroxy‐(PPO‐PDMS‐PPO) prepolymer into the copolyester chains was controlled by chloroform extraction. The effect of the structure and composition of the copolymers on the transition temperatures (T_m and T_g) and the thermal and thermo‐oxidative degradation stability, as well as on the degree of crystallinity, and some rheological properties, were studied. Copyright © 2006 Society of Chemical Industry     

Synthesis and properties of poly(imide siloxane) block copolymers with different block lengths

Several poly(imide siloxane) block copolymers with the same bis(γ‐aminopropyl)polydimethylsiloxane (APPS) content were prepared. The polyimide hard block was composed of 4,4′‐oxydianiline and 3,3′,4,4′‐diphenylthioether dianhydride (TDPA), and the polysiloxane soft block was composed of APPS and TDPA. The length of polysiloxane soft block increased simultaneously with increasing the length of polyimide hard block. For better understanding the structure–property relations, the corresponding randomly segmented poly(imide siloxane) copolymer was also prepared. These copolymers were characterized by FT‐IR, ¹H‐NMR, dynamic mechanical thermal analysis, thermogravimetric analysis, polarized optical microscope, rheology and tensile test. Two glass transition temperatures (T_g) were found in the randomly segmented copolymer, while three T_gs were found in the block copolymers. In addition, the T_gs, storage modulus, tensile modulus, solubility, elastic recovery, surface morphology and complex viscosity of the copolymers varied regularly with increasing the lengths of both blocks. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effects of the solubility parameter of polyimides and the segment length of siloxane block on the morphology and properties of poly(imide siloxane)

The dependence of morphology of the poly(imide siloxane)s (PISs) on the solubility parameter of unmodified polyimides and the molecular weight and content of α,ω‐bis(3‐aminopropyl) polydimethylsiloxane (APPS) has been studied. The effect of the morphology on the mechanical properties is also under investigation. The domain formation in the PISs with the APPS molecular weight M_n = 507 g/mol is not found until the mol ratio of APPS/PIS ≥ 0.5% in the pyromellitic dianhydride/p‐phenylene diamine (PMDA/p‐PDA)‐based PISs, and at a mol ratio ≥ 2.7% in the 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride/2,2′‐bis[4‐(3‐aminophenoxy) phenyl] sulfone (BTDA/m‐BAPS)‐based PISs. As the APPS M_n = 715 g/mol, the critical APPS concentrations of the domain formation in both types of PISs are equal to 0.1 and 1.1%, respectively. The critical concentration is equal to 0.6% in the BTDA/m‐BAPS‐based PIS film with the APPS M_n = 996 g/mol. The isolated siloxane‐rich phase in the BTDA/m‐BAPS‐based PISs becomes a continuous phase as the mol ratio of APPS/PIS ≥ 7.7, 10.0, and 16.6% as the APPS M_n = 996, 715, and 507 g/mol, respectively. Dynamic Mechanical Analysis (DMA) shows two T_gs in the PIS films having phase separation: one at −118 ∼ –115°C, being the siloxane‐rich phase, the other at 181–244°C, being the aromatic imide‐rich phase. The SEM micrographs show a significant deformation on the fractured surfaces of the BTDA/m‐BAPS‐based PIS films with a continuous siloxane‐rich phase. This phenomenon of plastic deformation is also observed in the tensile tests at −118°C and at room temperature. The highest elongation in the PIS films is found at the critical siloxane content of the continuous siloxane‐rich phase formation. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2832–2847, 1999     

Factors influencing thermal,mechanical, optical,and adhesive properties of segmented poly(imide siloxane) copolymers films

Poly(imide siloxane), block and blend copolymer, were synthesized using different methods to explore the influence of siloxane chains. The flexible siloxane chains enrichment on surface of copolymer, enhance hydrophobic and adhesive with copper foil. It also improves light transmittance of polyimide film in the visible light region. The effect of different preparation methods on the aggregation in polymers and on polymer properties, especially adhesion and water absorptivity, are also discussed. The imidization temperature and synthesis method (blend and block) during the reaction has a significant effect on the properties of the product, especially thermal properties (T _g values are 207 °C for block and 180 °C for blend) and mechanical properties (elongation of 130% for block and 50% for blend). The bonding strength of polymer films used as hot melt adhesive was also tested. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48148.     

Poly(amides) and poly(imides) containing silicon and germanium in the main chain: Synthesis,characterization and thermal studies

Poly(amides) and poly(imides) containing the heteroatoms Si or Ge in the main chain and bonded to four carbon atoms were synthesized and characterized by IR and ¹H, ¹³C and ²⁹Si NMR. The acid dichlorides bis(4‐chloroformylphenyl)‐dimethylgermane, bis(4‐chloroformylphenyl)‐diphenylgermane, bis(4‐chloroformylphenyl)‐dimethylsilane, and bis(4‐chloroformylphenyl)‐diphenylsilane were synthesized from the ditolyl derivatives, which were oxidized to the respective diacids. The dianhydrides bis(3,4‐dicarboxyphenyl)‐dimethylgermane dianhydride, bis(3,4‐dicarboxyphenyl)‐diphenylgermane dianhydride, bis(3,4‐dicarboxyphenyl)‐dimethylsilane dianhydride, and bis(3,4‐dicarboxyphenyl)‐diphenylsilane dianhydride were synthesized from the dixylyl derivatives, which were oxidized to the tetraacids. Fully aromatic diamines also containing Si or Ge were synthesized from 4‐bromo‐N,N‐bis(trimethylsilyl)‐aniline and diphenyl‐dichlorosilane or germane. The ditolyl and dixylyl derivatives were synthesized from 4‐bromo‐toluene or 4‐bromo‐xylene and dimethyl‐ or diphenyl‐dichlorogermane, dimethyl‐ or diphenyl‐dichlorosilane. The glass transition temperatures and the thermal stability were determined showing in general that the polymers with Si atom in the main chain presented higher values of both parameters due to the higher ionic character of the C? Si bond compared with the C? Ge one, and due to the lower size of the Si atom that presents lower rotational barriers. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 2768–2776, 2006     

Synthesis and physical properties of poly(l‐lactic acid)‐poly(dimethyl siloxane) multiblock copolymers prepared by direct polycondensation

Multiblock copolymers consisting of poly(l ‐lactic acid) and poly(dimethyl siloxane) were prepared by the polycondensation of oligo(l ‐lactic acid) (OLLA) with dihydroxyl‐terminated oligo(dimethyl siloxane) and dicarboxyl‐terminated oligo(dimethyl siloxane). Copolymers with number‐average molecular weights of 18,000?33,000 Da and various content ratios of oligo(dimethyl siloxane) (ODMS) unit were obtained by changing the feed ratio of these oligomers. A film prepared from the copolymer with an ODMS content ratio of 0.37 exhibited two independent peaks at ?107°C and 37°C in the mechanical loss tangent for temperature dependence, suggesting the formation of microphase separation between the OLLA and ODMS segments. The film had a tensile strength of 3.2 MPa and a high elongation of 132%. The film also exhibited a high strain recovery even after repeated straining. The incorporation of dimethyl siloxane units as multiblock segments was confirmed to improve the flexibility of poly(l ‐lactic acid). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40211.     

Processability,rheology, and thermal,mechanical, and morphological properties of postconsumer poly(vinyl chloride) bottles and cables

The processability, rheology, and thermal, mechanical, and morphological properties of three different commercial poly(vinyl chloride) (PVC) compounds blended with postconsumer PVC bottles and PVC cables were examined with respect to the recycled PVC content. The addition of PVC bottle recyclates [recycled bottles (RBs)] into virgin PVC bottle (VB) and virgin PVC pipe (VP) compounds caused a progressive reduction in the average torque. No thermal degradation or color change in the RB‐blended PVC compounds used was detected through carbonyl and polyene indices from IR analysis. The rheological properties for VP compounds were more sensitive to RB addition than those of VB compounds. The extrudate swell ratio did not change with the RB content. The decomposition temperature for the VB and VP compounds increased at 60–80% RB, whereas the glass‐transition temperature was unaffected by the RB loading. The 20 and 80 wt % RB loadings were recommended for the VB and VP compounds, respectively, for the optimum impact strength, the blends showing ductile fracture with a continuous phase. At the optimum impact and tensile properties, introducing RB recyclates into the VB compounds gave better results than the VP compounds. The hardness and density of the VB and VP compounds did not change with the RB content. The RB property change was comparatively faster than that of recycled PVC pipes. Adding the PVC cable recyclate [recycled cable (RC)] to virgin PVC cable (VC) had no obvious effect on the torque value of the RC/VC blends. The decomposition temperatures of the RC/VC blends stabilized at 20–60% RC and tended to decrease at 80% RC. The ultimate tensile stress was improved by the addition of the RC compounds, whereas the hardness and density of the VC compounds were unaffected by the RC content. It was concluded that the optimum concentrations of PVC recyclates to be added to virgin PVC compounds were different from one property to another and also depended on the type of virgin PVC grade used. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2738–2748, 2003     

Poly(aryl ether ketone)s containing dibenzoylbiphenyl groups: dynamic mechanical and physical ageing behaviour

The dynamic mechanical and physical ageing behaviour of a series of isomeric poly(aryl ether ketone)s containing 2,2′- and 3,3′-dibenzoylbiphenyl groups has been determined. A secondary γ-process, which was detected in all polymers by dynamic mechanical analysis, was both broader and located at higher temperatures in the 3,3′ polymers; this was attributed to greater intermolecular cooperativity and a higher effective relaxation time, arising from the more densely packed chains. The enthalpy relaxation of a pair of isomers was analysed using a common multi-parameter model for structural relaxation. The equilibrium enthalpy lost by the aged glass showed good agreement with the value extrapolated from the liquid state. Although the enthalpy lost by the equilibrium glass was identical for each isomer, the 3,3′ substituted polymer required a longer time to reach equilibrium and showed a greater dependence of physical ageing on structure. The higher density of the 3,3 isomer resulted in a slowing of both the physical ageing and the mechanical relaxation process. © 1999 Society of Chemical Industry     

Fusion,electrical conductivity,thermal, and mechanical properties of rigid poly(vinyl chloride) (PVC)/carbon black (CB) composites

Rigid and conductive poly(vinyl chloride) (PVC)/carbon black (CB) composites were prepared in a Haake torque rheometer. The results illustrate that the fusion torque of the PVC/CB composite is increased as the amount of CB is increased. Both the fusion percolation threshold and the fusion time of PVC/CB composites are decreased when the amount of CB is increased. Two major weight loss stages are observed in the TGA curve of PVC/CB composite. The first thermal degradation onset temperature (T_onset1) of PVC/CB composite is decreased as the amount of CB is increased. Both the first and second weight loss stages (ΔY₁ and ΔY₂) of PVC/CB composites are decreased as the amount of CB is increased. The surface resistivity of PVC/CB composite remains almost constant up to 6 parts per hundred unit weight of resin (phr) CB. When the amount of CB in PVC/CB composite is increased from 6 to 15 phr, the surface resistivity of PVC/CB composite is dramatically decreased from 10¹⁰ Ω/sq to 10⁴ Ω/sq. Because of the addition of CB, the rigidity of PVC/CB composite is increased and thus the mechanical properties, such as yield strength, tensile strength, and the Young's modulus, are improved. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

The effect of the mass ratio of hard and soft segments on some properties of thermoplastic poly(ester‐siloxane)s

A series of thermoplastic elastomers based on soft polydimethylsiloxane (PDMS) and hard poly(butylene terephthalate) (PBT) segments was synthesized using a two‐step transesterification reaction in the melt. The molar mass of the soft PDMS component was constant (M?_nPDMS = 1056 g mol^?1) while the starting reaction mixture compositions were varied to obtained copolymers with a mass ratio of hard to soft segments in the range from 70/30 to 40/60. The structure and composition of the copolymers was verified by ¹H NMR spectroscopy. It appeared that there was a pronounced molar mass maximum when the PBT content of the copolymers was approximately 60 mass%, whereas all samples were considerably inhomogeneous with respect to the distribution of the lengths of the hard segments. Differential scanning calorimetry (DSC) thermograms showed that the melting and crystallization temperature increased with increasing PBT content, as did the total degree of crystallinity, which was confirmed by wide‐angle X‐ray scattering (WAXS) analysis. Thermogravimetric analysis (TGA) performed in nitrogen gave subtle differences for samples of different composition, including that of the PBT homopolymer, whereas in oxygen these differences were more pronounced in the way the thermo‐oxidative stability of the obtained copolymers decreased with decreasing PBT content. Finally, it was shown that the hardness depended directly on the PBT content, ie the higher the PBT content, the greater the hardness of the corresponding copolymer. Copyright © 2004 Society of Chemical Industry