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A Vanillin-Derived,DOPO-Contained Bisphenol as a Reactive Flame Retardant for High-Performance Epoxy Thermosets 被引量:2
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作者 Li Wang Rongbai Tong +4 位作者 Juanli Wang Jintao Wan Yuhu Li Pujun Jin Daodao Hu 《Journal of Renewable Materials》 SCIE EI 2022年第5期1349-1364,共16页
Quest for bio-based halogen-free green flame retardant has attracted many concerns in recent years.Herein a reactive functional flame retardant containing phosphorus VDP is synthesized from vanillin,9,10-dihydro-9-oxa... Quest for bio-based halogen-free green flame retardant has attracted many concerns in recent years.Herein a reactive functional flame retardant containing phosphorus VDP is synthesized from vanillin,9,10-dihydro-9-oxa-10-phosphophene-10-oxide(DOPO)and phenol via a facile way.VDP is characterized with^(1)H NMR,^(31)P NMR,FTIR and Time of Flight Mass Spectrometry,and used as a new reactive flame retardant for bisphenol epoxy thermosets.Thermogravimetry analysis shows that when the VDP loading is only 0.5P%(based on phosphorus content),the residue increases from 14.2%to 21.1%at 750℃ in N_(2)compare with neat DGEBA.Correspondingly,the limit oxygen index increased to 29.6%,and flame retardancy reaches UL-94 V0 grade.Micro combustion calorimetry(MCC)and cone calorimetry analyses demonstrate that VDP can significantly lower flammability of the epoxy thermoset.With only 0.5P%of VDP,the heat release rate,total heat release rate and smoke production are reduced markedly.At the same time,the mechanical properties of the modified epoxy thermosets are also improved.The impact strength increases by 34%and the flexural strength increased by 23%,with 1.5P%of VDP.In short,VDP not only improves the flame retardancy,but also improves the mechanical properties of the epoxy thermosets. 展开更多
关键词 Epoxy resin bio-based flame retardant VANILLIN properties of thermosets
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A New DOPO-Eugenol Adduct as an Effective Flame Retardant for Epoxy Thermosets with Improved Mechanical Properties 被引量:1
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作者 Daqin Zhang Chufeng Yang +5 位作者 Huayang Ran Juanli Wang Jintao Wan Yuhu Li Pujun Jin Daodao Hu 《Journal of Renewable Materials》 SCIE EI 2022年第7期1797-1811,共15页
The development of efficient green flame retardants is an important way to realize more sustainable epoxy thermosets and downstream materials.In this work,a monoepoxide is synthesized through O-glycidylation of eugeno... The development of efficient green flame retardants is an important way to realize more sustainable epoxy thermosets and downstream materials.In this work,a monoepoxide is synthesized through O-glycidylation of eugenol,and then reacted with DOPO(9,10-dihydro-9-oxa-10-phosphophenanthrene-10-oxide)to obtain a new bio-based flame retardant,DOPO-GE.DOPO-GE is blended with a bisphenol A epoxy prepolymer exhibiting good compatibility and DDS(4,4′-diaminodiphenylsulfone)is used as the curing agent to afford epoxy thermosets.Although DOPO-GE leads to the reduced glass transition temperature of the thermosets,the storage modulus increases considerably.The DOPO-GE-modified thermosets exhibit the high thermal stability with the onset thermal decomposition temperature in nitrogen and air exceeding 300℃.When the phosphorus content in the thermoset is 1.0%,the residual yield of the thermosets at 750℃ in nitrogen increases from 13.9%to 30.6%,due to the increased charring ability.More interestingly,when the phosphorus content is only 0.5%,the limiting oxygen index is as high as 30.3%with UL94 V0 achieved.Cone calorimeter results reveals the significantly decreased heat release rate,total heat release,mass loss and total smoke production.Furthermore,DOPO-GE can notably improve the flexural strength,flexural modulus and fracture toughness,whereas the shear and impact strength are reduced to varied extents.In short,DOPO-GE can be obtained via a facile way,and shows the good flame-retardant effect on the epoxy thermosets with an application potential. 展开更多
关键词 Flame retardant epoxy thermosets bio-based additives PERFORMANCES
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Chemical and Morphological Surface Modification of Epoxy Based Thermosets
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作者 Marcela E. Penoff Patricia A. Oyanguren +1 位作者 Wido Schreiner Pablo E. Montemartini 《Materials Sciences and Applications》 2013年第7期1-9,共9页
Recently developed low fluorine containing polymers are advanced materials which confer advantageous properties to surfaces at a lower cost than conventional fluoropolymers (like PTFE), and are also more easily proces... Recently developed low fluorine containing polymers are advanced materials which confer advantageous properties to surfaces at a lower cost than conventional fluoropolymers (like PTFE), and are also more easily processable. Fluoropolymer surfaces are characterized by a low surface energy, high oleo and hydrophobicity, low coefficients of friction, among many other properties. This makes them desired materials in microelectronics, antifogging, antifouling and medical applications, to name a few. Fluorinated compounds are not easily coupled with macromolecules or common organic systems, and great efforts are made to compatibilize fluorinated species with hydrocarbon polymers. In this work, two chemical routes were explored in order to incorporate perfluorinated alkyl chains in an epoxy-amine based thermoset. On one side, a perfluoroalkyl thiolated molecule was used as a stabilizing ligand for silver nanoparticles, which were incorporated in the matrix polymer. On the other hand, fluorinated chains containing epoxy functionalities, were used as the matrix modifier. In the first case, fluorinated chains covering the nanoparticles, were mixed with the matrix, while in the second case, the fluoroalkyl chains were chemically linked to the network. Fluorine migration to the air—polymer interface was confirmed by X-Ray photoelectron spectroscopy (XPS). The materials hydrophobicity was then studied in terms of their contact angle with water (CA), as a function of the surface composition and the topography. Scanning electron microscopy (SEM) and atomic force microscopy (AFM), operated in moderate and light tapping modes, were used to morphologically describe the surfaces. An exhaustive surface analysis was made in order to explain the different hydrophobicity grades found. 展开更多
关键词 FLUOROPOLYMER Nanoparticles THERMOSET Surface HYDROPHOBIC
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Synthesis of CO_(2)-Based Re-processable Slight Cross-Linked Polyurea Thermosets
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作者 Huang Wenhan Jiang Shan +2 位作者 Li Hui Zhao Fengyu Cheng Haiyang 《有机化学》 SCIE CAS CSCD 北大核心 2024年第10期3178-3184,共7页
The use of CO_(2) as monomer to synthesize polymer materials is an important and potential applications topic from the viewpoint of green and sustainable chemistry.A new kind of CO_(2)-based polyurea(PUa)was synthesiz... The use of CO_(2) as monomer to synthesize polymer materials is an important and potential applications topic from the viewpoint of green and sustainable chemistry.A new kind of CO_(2)-based polyurea(PUa)was synthesized by polycondensation of CO_(2) with 4,7,10-trioxa-1,13-tridecanediamine and tris(2-aminoethyl)amine(TAEA).TAEA was used as cross-link reagent.The mechanical properties of PUa were significantly improved by inserted the crosslink agent of TAEA.The formed slight cross-linked PUa exhibited excellent mechanical properties with tensile strength of 26.8 MPa,elongation at break of 34%and Young’s modulus of 351 MPa.Moreover,it could be remolded for 3 times without obvious change in the mechanical properties,which are ascribed to the hydrogen bonding interaction among the main chains and the slight cross-linked structure.In addition,the synthesized CO_(2)-based PUa is of outstanding thermal performance with an initial decomposition temperature above 300℃,besides it is tolerance for a variety of organic solvents. 展开更多
关键词 CO_(2) POLYUREA non-isocyanate re-processable THERMOSET slight cross-linking
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Synthesis of multifunctional monomers from rosin for the properties enhancement of soybean-oil based thermosets 被引量:3
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作者 LIU Yuan LI Chao +3 位作者 DAI JinYue JIANG YanHua LIU XiaoQing ZHU Jin 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2017年第9期1332-1338,共7页
Two kinds of rosin derivatives, (2-hydroxy-3-(methacryloyloxy)propyl 7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,4b,5,6,10,10a- decahydrophenanthrene-1-carboxylate) (HMPIDDC) and (((7-isopropyl-1,4a-dimethyl-1,2,3,4... Two kinds of rosin derivatives, (2-hydroxy-3-(methacryloyloxy)propyl 7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,4b,5,6,10,10a- decahydrophenanthrene-1-carboxylate) (HMPIDDC) and (((7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octahydrophenan- thren-1-yl)methyl)azanediyl)bis(2-hydroxypropane-3,1-diyl)bis(2-methylacrylate) (IDOMAHM) were synthesized under mild and easy to implement conditions. The two derivatives were employed as the rigid monomers to copolymerize with acrylated epoxidized soybean oil (AESO), as so to improve the performance of the cured resins. The chemical structures of HMPIDDC and IDOMAHM were confirmed by nuclear magnetic resonance (NMR) and Fourier Transform Infrared (FT-IR) before copolymerization. The curing behaviors of pristine AESO, AESO/HMPIDDC blend, and AESO/IDOMAHM blend were monitored by differential scanning calorimetry (DSC). Moreover, the thermal and mechanical properties of the cured resins were evaluated by universal mechanical testing, dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). The results demonstrated that after the introduction of HMPIDDC and IDOMAHM, the glass transition temperature and mechanical properties of the copolymerized resin were significantly increased. In one word, HMPIDDC and IDOMAHM showed dramatic potential to be used as bio-based compounds to improve the properties of soybean-oil based thermosets. 展开更多
关键词 rosin derivatives bio-based compound rigid monomer thermosets
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Tailoring the Properties of Diels-Alder Reaction Crosslinked High-performance Thermosets by Different Bismaleimides 被引量:2
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作者 Kai-Ju Luo Li-Bo Huang +3 位作者 Yan Wang Jun-Rong Yu Jing Zhu Zu-Ming Hu 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2020年第3期268-277,I0007,共11页
A series of Diels-Alder reaction cross-linked thermosets with recyclability and healability were prepared from furan-containing aromatic polyamide and bismaleimides with different chemical structures.The structures of... A series of Diels-Alder reaction cross-linked thermosets with recyclability and healability were prepared from furan-containing aromatic polyamide and bismaleimides with different chemical structures.The structures of synthesized bismaleimides were confirmed by 1 H nuclear magnetic resonance(1 H-NMR)spectroscopy;their reversible cross-linking with the furanic polyamide was further detected by 1 H-NMR technique and sol-gel transition behavior.The dynamic mechanical analysis and tensile test revealed the variable thermal and mechanical properties of thermosets cross-linked by different bismaleimides and with different molar ratios of maleimide group to furan group(Ima/fur).The tensile test also demonstrated that the better recyclability and solvent-assisted healability of thermosets cross-linked could be achieved by more flexible bismaleimides.This work is expected to provide valuable information for design of recyclable and healable high-performance thermosets with desired properties. 展开更多
关键词 RECYCLABILITY Reparability thermosets Diels-Alder reaction
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Synthesis of renewable isosorbide-based monomer and preparation of the corresponding thermosets 被引量:1
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作者 Bing-Tao Wang Fu-De Lu +2 位作者 Feng Xu Yu-Zhan Li Michael R.Kessler 《Chinese Chemical Letters》 SCIE CAS CSCD 2016年第6期875-878,共4页
Two kinds of difunctionalized isosorbide derivatives containing norbornene groups were designed and synthesized by a facile one-step reaction under mild conditions.~1H NMR spectroscopy confirmed the chemical compositi... Two kinds of difunctionalized isosorbide derivatives containing norbornene groups were designed and synthesized by a facile one-step reaction under mild conditions.~1H NMR spectroscopy confirmed the chemical composition and differential scanning calorimetry(DSC) revealed the distinct curing behaviors between conventional petroleum-based dicyclopentadiene(DCPD) and synthesized renewable isosorbided-based monomer(ISN). In contrast to DCPD, ISN was low viscous liquid at room temperature and had even higher reactivity to perform ring-opening metathesis polymerization(ROMP) in the presence of Grubbs' catalyst. Due to the presence of flexible and elastic Si–C long chains, the cured poly(ISN) thermosets not only had good mechanical properties but also exhibited much higher storage modulus at the rubbery state in comparison with traditional poly(DCPD). 展开更多
关键词 ISOSORBIDE Norbornenyl functionality ROMP thermosets
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Intrinsically Anti-Flammable Apigenin-derived Epoxy Thermosets with High Glass Transition Temperature and Mechanical Strength 被引量:1
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作者 Hafezeh Nabipour Xin Wang +1 位作者 Lei Song Yuan Hu 《Chinese Journal of Polymer Science》 SCIE EI CAS CSCD 2022年第10期1259-1268,I0011,共11页
In this work,apigenin was chosen as a raw material to synthesize a novel epoxy monomer(DGEA),while the bio-based epoxy resin was further obtained after curing with 4,4’-diaminodiphenylmethane(DDM).The control samples... In this work,apigenin was chosen as a raw material to synthesize a novel epoxy monomer(DGEA),while the bio-based epoxy resin was further obtained after curing with 4,4’-diaminodiphenylmethane(DDM).The control samples were prepared by curing diglycidyl ether of bisphenol A(DGEBA)with DDM.The non-isothermal differential scanning calorimeter(DSC)method was utilized to further investigate the curing behavior and curing kinetics of the DGEA/DDM system.Despite no flame retardant active elements,the DGEA/DDM thermoset still exhibited exceptional anti-flammability.Specifically,the DGEA/DDM thermoset reached a V-0 rating in the UL-94 test and owned a high limiting oxygen index(LOI)value of 37.0%,while DGEBA/DDM resins were consumed completely in the vertical combustion test with a low LOI of 23.0%.Furthermore,the microscale combustion calorimetry(MCC)results manifested that compared with DGEBA/DDM resins,both PHRR and THR values of the DGEA/DDM resins were dropped by 84.0%and 57.6%,respectively.Additionally,the DGEA/DDM resin also presented higher storage modulus and tensile strength compared with DGEBA/DDM one.Particularly,in contrast with that of the cured DGEBA/DDM one(156℃),the DGEA/DDM thermoset displayed an extremely high glass transition temperature(232℃).This study breaks new ground on how to produce biobased monomers with aromatic structures and achieve high-performance thermosetting polymers. 展开更多
关键词 Bio-based epoxy thermosets APIGENIN Intrinsic anti-flammability
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Recyclable Technology of Thermosetting Resins for High Thermal Conductivity Materials Based on Physical Crushing
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作者 An Zhong Congzhen Xie +8 位作者 Bin Gou Jiangang Zhou Huasong Xu Song Yu Daoming Zhang Chunhui Bi Hangchuan Cai Licheng Li Rui Wang 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第6期378-387,共10页
Epoxy resin,characterized by prominent mechanical and electric-insulation properties,is the preferred material for packaging power electronic devices.Unfortunately,the efficient recycling and reuse of epoxy materials ... Epoxy resin,characterized by prominent mechanical and electric-insulation properties,is the preferred material for packaging power electronic devices.Unfortunately,the efficient recycling and reuse of epoxy materials with thermally cross-linked molecular structures has become a daunting challenge.Here,we propose an economical and operable recycling strategy to regenerate waste epoxy resin into a high-performance material.Different particle size of waste epoxy micro-spheres(100–600μm)with core-shell structure is obtained through simple mechanical crushing and boron nitride surface treatment.By using smattering epoxy monomer as an adhesive,an eco-friendly composite material with a“brick-wall structure”can be formed.The continuous boron nitride pathway with efficient thermal conductivity endows eco-friendly composite materials with a preeminent thermal conductivity of 3.71 W m^(−1)K^(−1) at a low content of 8.5 vol%h-BN,superior to pure epoxy resin(0.21 W m^(−1)K^(−1)).The composite,after secondary recycling and reuse,still maintains a thermal conductivity of 2.12 W m^(−1)K^(−1) and has mechanical and insulation properties comparable to the new epoxy resin(energy storage modulus of 2326.3 MPa and breakdown strength of 40.18 kV mm^(−1)).This strategy expands the sustainable application prospects of thermosetting polymers,offering extremely high economic and environmental value. 展开更多
关键词 brick-wall structure epoxy thermosetting physical recycling thermal management
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EXPERIMENTAL STUDY ON PEK -C MODIFIED EPOXIES AND THE CARBON FIBER COMPOSITES FOR AEROSPACE APPLICATION 被引量:7
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作者 李暘暘 益小苏 唐邦明 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2000年第4期242-249,共8页
The morphological structure of various epoxies toughened with a special amorphous thermoplastic PEK-C and their carbon fiber composites were studied by using SEM. For both cases, phase separation and inversion took pl... The morphological structure of various epoxies toughened with a special amorphous thermoplastic PEK-C and their carbon fiber composites were studied by using SEM. For both cases, phase separation and inversion took place to form fine epoxy-rich globules dispersing in the PEK-C matrix, in which the epoxy-rich phase had the absolutely higher volume fraction. The phase structure and the interfacial properties were also studied by means of FTIR, DSC, and DMTA as well. An accompanying mechanical determination revealed that an improved toughness was achieved both in the blend casts and in the carbon fiber composites. A composite structural model was hence suggested. 展开更多
关键词 PEK-C thermoset/thermoplastic binary system phase behavior interface TOUGHNESS carbon fiber composites
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Thermally Reversible,Self-Healing Polyurethane Based on Propyl Gallate and Polyurethane Prepolymers with Varied Isocyanate Content 被引量:2
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作者 Haiyang Ding Xiaohua Yang +3 位作者 Lina Xu Shouhai Li Jianling Xia Mei Li 《Journal of Renewable Materials》 SCIE EI 2020年第1期1-11,共11页
Thermosetting polyurethanes are widely used in various fields owing to their excellent elasticity,strength and solvent resistance.Three environmental friendly propyl gallate-based self-healing polyurethanes were prepa... Thermosetting polyurethanes are widely used in various fields owing to their excellent elasticity,strength and solvent resistance.Three environmental friendly propyl gallate-based self-healing polyurethanes were prepared from polyurethane prepolymers with varying isocyanate content.The thermal stabilities of the polyurethanes were tested using thermogravimetric analysis.Their self-healing and mechanical properties were analyzed using a universal testing machine and dynamic thermomechanical analysis.The polyurethanes were found with high self-healing ability and excellent mechanical properties due to the absence of phenolic carbamate.These qualities improved with increased isocyanate content and the prolonged selfhealing time.We found,therefore,that the propyl gallate-based polyurethane has potential for use in industrial applications as self-healing materials. 展开更多
关键词 Propyl gallate thermosetting polyurethane self-healing ability mechanical property
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Mechanical Properties of Carbon Epoxy Prepreg Insert Phenolic Resin Injection Moldings 被引量:2
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作者 PINPATHOMRAT Badin KEIGO Nishitani +3 位作者 THUMSORN Supaphom Narongchai O-Charoen Yuqiu YANG HAMADA Hiroyuki 《纤维复合材料》 CAS 2019年第2期3-7,共5页
This study focuses on the insert-injection molding process. The thermoset composite inserts in this study were carbon fiber/epoxy (CF/Epoxy) prepreg sheets. The injected molded part was glass fiber contained phenolic ... This study focuses on the insert-injection molding process. The thermoset composite inserts in this study were carbon fiber/epoxy (CF/Epoxy) prepreg sheets. The injected molded part was glass fiber contained phenolic resin (GF/PF). The CF/Epoxy was placed in the mold cavity prior to injecting GF/PF onto the inserted injection molded CF/Epoxy specimens. The role of adhesion between the inserted part and injected resin on the mechanical properties was evaluated by 3 point bending and impact tests. In addition, the effect of prepreg orientation on the mechanical properties of the prepreg inserted-injection molding system was investigated. It was found that the prepreg with unidirectional orientation significantly improved flexural and impact strength of the inserted injection molding composites, providing better support and resistance to bending and impact loading. The main failure modes of the specimens were structural and adhesive failure. 展开更多
关键词 INSERT injection MOLDING UNIDIRECTIONAL prepregs woven fabric PREPREG THERMOSETTING composite
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Recent research progress on quasi-solid-state electrolytes for dye-sensitized solar cells 被引量:1
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作者 Asif Mahmood 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2015年第6期686-692,共7页
Dye-sensitized solar cells (DSSCs) are the most promising, low cost and most extensively investigated solar cells. They are famous for their clean and efficient solar energy conversion. Nevertheless this, long-time ... Dye-sensitized solar cells (DSSCs) are the most promising, low cost and most extensively investigated solar cells. They are famous for their clean and efficient solar energy conversion. Nevertheless this, long-time sta- bility is still to be acquired. In recent years research on solid and quasi-solid state electrolytes is extensively in- creased. Various quasi-solid electrolytes, including composites polymer electrolytes, ionic liquid electrolytes, thermoplastic polymer electrolytes and thermosetting polymer electrolytes have been used. Performance and stability of a quasi-solid state electrolyte are between liquid and solid electrolytes. High photovoltaic performances of QS-DSSCs along better long-term stability can be obtained by designing and optimizing quasi-solid electrolytes. It is a prospective candidate for highly efficient and stable DSSCs. 展开更多
关键词 Dye-sensitized solar cells Quasi-solid electrolytes Composites polymer electrolytes Ionic liquid electrolytes Thermoplastic polymer electrolytes and thermosetting polymer electrolytes
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Kinetic Laws of Heating Initiated Reactions for Materials in Aerospace Applications 被引量:3
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作者 QIAO Haitao WANG Zhiyong SONG Jiangpeng 《Aerospace China》 2021年第3期54-61,共8页
Cure and decomposition reaction kinetics of typical organic materials in aerospace applications are introduced.From the data of dynamic differential scanning calorimetry(DSC)experiments,and based on changes of the pea... Cure and decomposition reaction kinetics of typical organic materials in aerospace applications are introduced.From the data of dynamic differential scanning calorimetry(DSC)experiments,and based on changes of the peak temperatures(T_(p))with different heating rates(β),a linear equation,T_(p)=T_(1)+△Tlnβ,has been obtained more reasonably.The above equation can be used to explain some laws of higher or lower of apparent activation energies(E_(a)),by which the apparent activation energy(E_(a))is nearly equal to RT^(2)_(1)/△T.A number of kinetic investigations of typical thermosetting resins and energetic materials in aerospace applications were chosen to validate the above equations. 展开更多
关键词 thermosetting resin energetic material CURE thermal decomposition reaction kinetics aerospace application
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Challenging multiphase complex fluids for applications
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作者 许元泽 《Journal of Central South University》 SCIE EI CAS 2008年第S1期130-134,共5页
Modern processing technology is calling the scientific understanding of dynamic processes,where the science of complex fluids plays a central role.We summarize our recent efforts using the generic approaches of multi-... Modern processing technology is calling the scientific understanding of dynamic processes,where the science of complex fluids plays a central role.We summarize our recent efforts using the generic approaches of multi-scale physics of complex fluids on apparently irrelevant processes,i.e.the mixing of polymer blends,the processing of thermoplastic(TP) toughened thermosetting(TS) composites using phase separation of TP in TS,as well as the enhanced oil recovery using polymer soft gel.It is emphasized that the thorough physical understanding in multi-scales of time and space through the joint efforts of experiment and theory in each scale is the key issue for the modeling of various processes. 展开更多
关键词 complex fluid MULTI-SCALE physics polymer BLEND phase separation THERMOSETTING composite soft GEL EOR
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PREPARATION AND PROPERTIES OF THERMOSETTING ACRYLIC COATINGS USING TITANIUM-OXO-CLUSTER AS A CURING AGENT
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作者 周树学 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2009年第3期351-358,共8页
Thermosetting acrylic coatings were prepared by using carboxyl acid group-containing acrylic oligomer and curing with titanium-oxo-clusters which were first pre-hydrolyzed from titanium n-butoxide.The curing ability o... Thermosetting acrylic coatings were prepared by using carboxyl acid group-containing acrylic oligomer and curing with titanium-oxo-clusters which were first pre-hydrolyzed from titanium n-butoxide.The curing ability of the titanium-oxo-cluster was examined using a microdielectric analytical(DEA)curing monitor,Fourier transformed infrared spectroscopy(FTIR),and Soxhlet extraction experiments,and the properties of the resulted coatings were investigated with pendulum hardness tester,dynamic mechanical analysis(DMA),thermogravimetric analysis(TGA)and ultraviolet-visible spectrometer.The effect of titania-oxo-cluster in leading acrylic oligomers to form thermosetting acrylic coatings was confirmed.An increasing pendulum hardness and modulus of acrylic coatings with increasing titania content was observed, which resulted from the increment of crosslinking degree rather than of the titania content.The thermosetting acrylic/titania coatings also showed better thermal stability and higher UV-blocking properties than those coatings using organic curing agent. 展开更多
关键词 Acrylic resin TITANIA Thermosetting coating Curing agent
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Spreading and Curing Behaviors of a Thermosetting Droplet-Silicone on a Heated Surface
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作者 Xingjian Yu Run Hu +2 位作者 Liliang Zhou Han Wu Xiaobing Luo 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2019年第4期1-8,共8页
Thermosetting materials are widely used as encapsulation in the electrical packaging to protect the core electronic components from external force, moisture, dust, and other factors. However, the spreading and curing ... Thermosetting materials are widely used as encapsulation in the electrical packaging to protect the core electronic components from external force, moisture, dust, and other factors. However, the spreading and curing behaviors of such kind of fluid on a heated surface have been rarely explored. In this study, we experimentally and numerically investigated the spreading and curing behaviors of the silicone(OE6550 A/B, which is widely used in the light-emitting diode packaging) droplet with diameter of ~2.2 mm on a heated surface with temperature ranging from 25 ℃ to 250 ℃. For the experiments, we established a setup with high-speed camera and heating unit to capture the fast spreading process of the silicone droplet on the heated surface. For the numerical simulation, we built a viscosity model of the silicone by using the Kiuna’s model and combined the viscosity model with the Volume of Fluid(VOF) model by the User Defined Function(UDF) method. The results show that the surface temperature significantly affected the spreading behaviors of the silicone droplet since it determines the temperature and viscosity distribution inside the droplet. For surface temperature varied from 25 ℃ to 250 ℃, the final contact radius changed from ~2.95 mm to ~1.78 mm and the total spreading time changed from ~511 s to ~0.15 s. By further analyzing the viscosity evolution of the droplet, we found that the decreasing of the total spreading time was caused by the decrease of the viscosity under high surface temperature at initial spreading stage, while the reduction of the final contact radius was caused by the curing of the precursor film. This study supplies a strategy to tuning the spreading and curing behavior of silicone by imposing high surface temperature, which is of great importance to the electronic packaging. 展开更多
关键词 THERMOSETTING material SILICONE SURFACE temperature SPREADING and CURING
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Thermal Polymerization of Cyanate Ester-Benzoxazine:Study of a Functional Model Compound
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作者 WANG Fan ZHOU Hui +3 位作者 WAN Li DONG Bin LI Shengchao QI Huimin 《上海航天(中英文)》 CSCD 2022年第1期122-128,161,共8页
A novel benzoxazine(BOZ)monomer is synthesized by a pot method with solvent-free to blend with cyanate ester(CE).A soluble intermediate is obtained after being cured for 20 h at 80℃.The two model compound and the ble... A novel benzoxazine(BOZ)monomer is synthesized by a pot method with solvent-free to blend with cyanate ester(CE).A soluble intermediate is obtained after being cured for 20 h at 80℃.The two model compound and the blends are analyzed with the infrared radiation(IR),nuclear magnetic resonance(NMR)spectroscopy,and differential scanning calorimetry(DSC).The results show that an intermediate of the iminocarbonate and BOZ structures is formed by the ring-open BOZ reacting with the cyanate groups and ring-unopened BOZ.Moreover,rearrangement and ring-opening occur in the postcure of the intermediate to form the alkyl isocyanurate structure with polybenzoxazine. 展开更多
关键词 thermosetting resin benzoxazine(BOZ) cyanate ester(CE)resin polymerization mechanism
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The Effect of Epoxy Concentration and Fibre Loading on the Mechanical Properties of ABS/Epoxy-Coated Kenaf Fibre Composites
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作者 Hafsat R. Saliu U. S. Ishiaku +4 位作者 M. K. Yakubu E. G. Kolawole S. S. Adefila M. B. Abu Bakar Z. A. Moh’d Ishak 《Open Journal of Composite Materials》 2015年第2期41-48,共8页
In this work, thermosetting resin, epoxy and fibre loading were used in optimizing the strength at which ABS/epoxy coated kenaf fibre (EKF) composites would perform apparently during mechanical stress. Kenaf bast fibr... In this work, thermosetting resin, epoxy and fibre loading were used in optimizing the strength at which ABS/epoxy coated kenaf fibre (EKF) composites would perform apparently during mechanical stress. Kenaf bast fibres were resin coated before incorporated into engineering thermoplastic ABS at its processing temperature (230&degC), cured in-situ at internal mixer and later compression moulded at 210&degC under 65 kg/cm2pressure. The results showed the optimum level of tensile strength with thermoset and fibre loading as well as increase in strong interfacial bonding while the hardness values increased with increasing thermosetting and fibre contents. Both the tensile and flexural modulus apparently increased as the fibre contents increased. 展开更多
关键词 THERMOSETTING Resin KENAF FIBRE Engineering THERMOPLASTIC ABS
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Respiratory Symptoms and Spirometry Profile of Plastic Factory Workers in Ogun State, Southwest Nigeria
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作者 John Omotola Ogunkoya Olumide Abiodun +6 位作者 Kolawole John Sodeinde Emmanuel Fikayo Bamidele John Sotunsa Akindele Emmanuel Ladele Omosivwe Oku George Ezinwa Emeruwa Olawale Kehinde Ogunyemi 《Occupational Diseases and Environmental Medicine》 2022年第2期60-70,共11页
Background: Exposure to plastic fumes can lead to severe occupational hazards due to inhalation, ingestion or direct contact wide variety of potentially harmful by-products during the manufacturing and burning of plas... Background: Exposure to plastic fumes can lead to severe occupational hazards due to inhalation, ingestion or direct contact wide variety of potentially harmful by-products during the manufacturing and burning of plastics. Objectives: To determine the prevalence of respiratory symptoms in plastic factory workers, evaluate the respiratory function of plastic factory workers and the association between respiratory symptoms and the duration of employment. Methods: This was a cross-sectional study done among plastic factory workers. Using a random sampling technique, 190 individuals (95 subjects and 95 control) above 18 years of age were recruited. Data were obtained with a validated questionnaire and Spirometry was done. Result: The mean age of the study group and control were 30.27 ± 7.38 and 25.92 ± 4.63 respectively (t = 4.877;p Conclusion: Workplace exposure to plastic fumes can lead to development of respiratory symptoms and impaired pulmonary function. 展开更多
关键词 Plasticos THERMOSET THERMOPLASTIC STYRENE 1 3-Butadiene Microplastics
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