Synthesis and properties of novel phosphorus‐containing hardener for epoxy resins

A novel phosphorus‐containing curing agent, 2‐(6‐oxid‐6H‐dibenz〈c,e〉〈1,2〉oxa‐phosphorin‐6‐yl) phenol formaldehyde novolac [OD‐PN], was prepared from phenol formaldehyde novolac resin (PN) and a reactive 2‐(6‐oxid‐6H‐dibenz〈c,e〉〈1,2〉oxa‐phosphorin‐6‐yl)chloride (ODC) while ODC was synthesized through reaction between o‐phenylphenol and phosphoryl trichloride. The compound (OD‐PN) was used as a reactive flame‐retardant in o‐cresol formaldehyde novolac epoxy resin (CNE) for electronic application. Owing to the rigid structure of ODC and pendant P group, the resulted phosphorus containing epoxy resin exhibited better flame retardancy, higher glass transition temperature, and thermal stability than the noncyclic P‐containing curing agent or the bromine containing flame‐retardant epoxy resin. UL 94‐VO rating could be achieved with a phosphorus content of as low as 1.21% (comparable to bromine content of 6%) in the cured resin, and no fumes and toxic gas emission were observed. The relationship between the structure and flammability for both phosphorus containing curing agents OD‐PN and TP‐PN (triphenyl phosphate‐phenol formaldehyde novolac reaction product) are also examined. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1636–1644, 2000     

Synthesis and characterization of copolyesters containing the phosphorus linking pendent groups

Poly(ethylene terephthalate)‐co‐poly(ethylene DDP)s [PET‐co‐poly(ethylene DDP)s], were synthesized by charging 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOP), itaconic acid, terephthalic acid, and ethylene glycol in one reactor to conduct the microaddition reaction (using H₂PtCl₆ as catalyst), esterification reaction, and polycondensation reaction. H₂PtCl₆ has demonstrated to be a highly efficient microaddition catalyst to improve the DDP conversion. The microaddition reaction of the phosphorus compound (DOP) with the itaconic acid can be proceeded at a significantly lower temperature (110°C) and results in higher conversion (> 98%). The use of the H₂PtCl₆ catalyst makes it possible to charge all the reactants in one reactor to produce high molecular weight phosphorus‐containing copolyesters without requiring the presynthesis of the DDP. These resulting copolyesters are identified by Fourier transform infrared spectroscopy, ¹H‐NMR, and differential scanning calorimetric analysis. Thermal characteristics, thermal stability, intrinsic viscosity, acid value, and rheological and mechanical properties of these copolyesters were also characterized. The presence of the bulky pendent phosphorus side groups in the copolyester tends to decrease the structural regularity and retards its crystallization. The formation of a protected char layer for the phosphorus‐containing copolyester raises the decomposition temperature of the copolyester under an oxygen atmosphere higher than that of PET. The limiting oxygen index values of all phosphorus‐containing copolyesters are all higher than 33. Higher phosphorus content results in decreasing crystallinity, lower melting temperature, lower decomposition temperature, as well as lower tensile strength, but increasing residual char after thermal degradation and higher limiting oxygen index value. The rheological behaviors of copolyesters remain similar to that of PET. The glass temperatures of copolyesters are all ∼ 77°C (76.8°–77.2°C). Incorporation of phosphorus moieties into its molecular chain has a significant effect on thermal and flame retardancy behavior. However, the crystal lattice of all copolyesters do not change with incorporation of the pendent phosphorus side group in the backbone of the copolyester. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 109–122, 1999     

Characterizations for blends of phosphorus-containing copolyester with poly(ethylene terephthalate)

High molecular weight phosphorus-containing copolyesters, poly(ethylene terephthalate)-co-poly(ethylene DDP) (PET-co-PEDDP)s, were prepared and characterized with the objective of producing a non-halogen flame retardant system for practical applications. The phosphorus-containing copolyester with 30 wt% phosphorus (P30 copolyester) was blended with PET to evaluate their characteristics and flame retardancy. Higher phosphorus content results in lower crystallinity and higher char formation after thermal degradation. The rheological behavior remains similar to that of PET. The P30/PET blend possesses higher crystallization rate than the corresponding phosphorus-containing copolyester containing equal phosphorus content. Thermal and rheological behaviors of P30/PET blends are similar to PET or the phosphorus-containing copolyesters. The P30/PET blends are miscible or compatible base on single T_gs detected by DSC or DMA. The SEM/EDX phosphorus mapping image of the P30/PET blend shows uniform distribution of the phosphorus moieties within the P30/PET matrix, another indication of a compatible or miscible blend between the phosphorus-containing copolyester P30 and PET. Flame retardancy of the P30/PET blend is identical to that of the phosphorus-containing copolyester with identical phosphorus content. Blending of high phosphorus content copolyester with virgin PET provides a feasible method to obtain a flame resistant PET with LOI greater than 28.     

PET纤维及其织物的阻燃技术进展

概述了聚对苯二甲酸乙二醇酯(PET)纤维及其织物的阻燃技术,包括共缩聚阻燃PET纺丝、PET与阻燃剂共混纺丝及PET织物阻燃后处理等。其中,阻燃剂主要有磷系及磷-氮系阻燃剂,如:9,10-二氢-9-氧杂-10-磷杂蒽-10-氧化物(DOPO)衍生物、次膦酸(酯)及其聚合物、氧化膦聚合物、膦酸酯及螺环磷酸酯等。今后应积极开发生态和环境兼容的阻燃PET纤维新技术。     

Phosphorus‐containing epoxy resin for an electronic application

A phosphorus‐containing epoxy resin, 6‐H‐dibenz[c,e][1,2] oxaphosphorin‐6‐[2,5‐bis(oxiranylmethoxy)phenyl]‐6‐oxide (DOPO epoxy resin), was synthesized and cured with phenolic novolac (Ph Nov), 4,4′‐diaminodiphenylsulfone (DDS), or dicyandiamide (DICY). The reactivity of these three curing agents toward DOPO epoxy resin was found in the order of DICY > DDS > Ph Nov. Thermal stability and the weight loss behavior of the cured polymers were studied by TGA. The phosphorus‐containing epoxy resin showed lower weight loss temperature and higher char yield than that of bisphenol‐A based epoxy resin. The high char yields and limiting oxygen index (LOI) values as well as excellent UL‐94 vertical burn test results of DOPO epoxy resin indicated the flame‐retardant effectiveness of phosphorus‐containing epoxy resins. The DOPO epoxy resin was investigated as a reactive flame‐retardant additive in an electronic encapsulation application. Owing to the rigid structure of DOPO and the pendant P group, the resulting phosphorus‐containing encapsulant exhibited better flame retardancy, higher glass transition temperature, and thermal stability than the regular encapsulant containing a brominated epoxy resin. High LOI value and UL‐94 V‐0 rating could be achieved with a phosphorus content of as low as 1.03% (comparable to bromine content of 7.24%) in the cured epoxy, and no fume and toxic gas emission were observed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 353–361, 1999     

Flame retardant performance of a carbon source containing DOPO derivative in PET and epoxy

The combination of gas‐phase and condensed‐phase action will contribute to high quality flame retardant. A novel 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO)‐based flame retardant (DOPO‐DOPC), which contains carbon source was synthesized in favor of conducting the effect of gas‐phase as well as promoting the char formation in condensed‐phase. The chemical structure of DOPO‐DOPC was characterized by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). DOPO–DOPC was used as an additive in poly(ethylene terephthalate) (PET) and epoxy resin (EP). The flame retardancy of PET/DOPO‐DOPC and EP/DOPO‐DOPC composites were studied by limiting oxygen index (LOI) and UL‐94 test. The results showed that the incorporation of DOPO–DOPC into PET or EP could obviously improve their flame retardancy. The LOI values of modified PET or EP, which contained 10 wt % DOPO‐DOPC reached 42.8 and 31.7%, respectively. The thermogravimetric analysis (TGA) results revealed that DOPO–DOPC enhanced the formation of char residues. The Laser Raman spectroscopy (LRS) was used to investigate the carbon structure of thermal oxidation residues. Because of the combination of the gas phase flame retardant effect of DOPO moiety and the promoting formation of char residues in condensed phase, the PET and EP composites exhibited significant improvement toward flame retardancy. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44639.     

Synthesis and characterization of main-chain liquid crystalline copolyesters containing phosphaphenanthrene side-groups

A series of thermotropic main-chain liquid crystalline copolyesters P1-P5 containing 2-(6-oxide-6H-dibenz〈c,e〉〈1,2〉oxaphosphorin-6-yl)-1,4-dihydroxyphenylene (ODOPB) as non-mesogenic unit and 4,4′-dihydroxybiphenyl (DB) as mesogenic unit were prepared by polycondensation with sebacoyl chloride. The thermal and mesogenic properties were characterized by differential scanning calorimetry (DSC), polarizing optical micrography (POM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). It was found that introducing of ODOPB into polyester decreased the melting temperature (Tm) and the isotropic temperature (Ti). The copolyesters P1-P5 exhibited mesomorphic properties even when the molar ratio of the non-mesogenic monomer ODOPB to mesogenic monomer DB reached 6:4 in feed. For explaining the effect of DOPO group on the mesomorphic properties, the X-ray diffraction analysis of a low molecular weight modal compound containing ODOPB was carried out and the results show that the DOPO side-group is parallel with the most-adjacent benzene ring in the main-chain, which reveals the small effect of ODOPB on the mesogenic structure of polyesters. The thermal analysis showed that the incorporation of phosphorus-containing moieties increase the residual char of the formed liquid crystalline polymers. The thermal stability, however, decreases because the OP-O bond is less stable than the common C-C bond.     

Synthesis and thermal properties of poly(ethylene 2,6‐naphthalate) copolyesters containing modified diacid monomer

A series of poly(ethylene 2,6‐naphthalate) (PEN) copolyesters was synthesized using three monomers (newly prepared 1,4‐bis[(methoxycarbonylethoxy)methyl]benzene, dimethyl 2,6‐naphthalenedicarboxylate, and ethylene glycol) with various molar ratios to investigate the effects of these compositions on thermal properties of the copolyesters. Copolyesters having weight average molecular weights of 11,000–22,000 were obtained by melt polycondensation in the presence of metallic catalysts. The structures and thermal properties of the resulting random PEN copolyesters were characterized by nuclear magnetic resonance, differential scanning calorimetry, thermal‐mechanical analyzer, and X‐ray diffraction analysis. The results of thermal measurements revealed that thermal properties depended on the corresponding new diacid comonomer content of the PEN copolyesters. Nonetheless, the crystal structures of PEN copolyesters and PEN homopolymer are identical. POLYM. ENG. SCI., 54:2641–2644, 2014. © 2013 Society of Plastics Engineers     

Tailoring block‐copolyesters by reactive blending of polyethylene terephthalate and polyethylene naphthalate using statistical design of experiments

Block‐copolyesters of polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) were synthesized via reactive extrusion. The influence of processing parameters on the material properties on a molecular scale like degree of trans‐esterification, block length, and degree of randomness were investigated. The varied process factors were extrusion temperature and rotational speed. The effects of process parameter variation were investigated by ¹H‐NMR‐spectroscopy. The experimental results show a clear dependence of the molecular properties on the processing conditions. By using statistical experimental design (DoE), it was possible to prepare defined copolyesters from PET and PEN without addition of further chemicals. With a degree of randomness between 0.05 and 0.5, the presence of an actual copolyester was confirmed when appropriate extrusion conditions were applied. The reactive extrusion process was confirmed to be suitable to produce defined block‐copolyesters in a predictable and reproducible way. It was possible to produce designed sequence lengths, which could be adjusted within a range of 11–136 repeating units in the case of PET and, in the case of PEN, of 2.5–26. The produced materials can be used as barrier materials or barrier coatings to protect substrates against molecular oxygen and water vapour, e.g., in organic photovoltaic applications or food packaging. The described method is a one‐pot alternative method to the previously described chemical recycling pathway. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41997.     

Improving thermal and flame‐retardant properties of epoxy resins by a novel reactive phosphorous‐containing curing agent

In an attempt to improve thermal and flame‐retardant properties of epoxy resins efficiently, a new reactive phosphorus‐containing curing agent called 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐yl‐(phenylimino)‐(4‐hydroxyphenyl)me‐thane (DOPO‐PHM) was synthesized and was combined with 4,4′‐diaminodiphenyl methane (DDM) to co‐cure epoxy resins (E51), which covalently incorporated halogen‐free DOPO organ groups into the epoxy networks. The chemical structure of this curing agent was confirmed by FTIR, 1D, and 2D NMR spectra. A reaction mechanism during the preparation was proposed, and the electron effect on the stabilization of the carbocation was discussed. Various DDM/DOPO‐PHM molar ratios were used to get the materials with different phosphorus contents. Their dynamic mechanical, thermal, and flame‐retardant properties were evaluated by dynamic mechanical thermal analysis, thermogravimetric analysis, and limiting oxygen index (LOI) respectively. All samples had a single T_g, showing that these epoxy resins were homogeneous phase for long‐term use in spite of adding DOPO‐PHM. Both char yields (under nitrogen and air atmospheres) increased with the increasing of phosphorus content and the LOI values increased from 24.5 for standard resin to 33.5 for phosphorus‐containing resins, indicating the significant enhancement of thermal stability and flame retardancy. POLYM. ENG. SCI., 54:1192–1200, 2014. © 2013 Society of Plastics Engineers     

An effective flame retardant for poly(ethylene terephthalate) synthesized by phosphaphenanthrene and cyclotriphosphazene

A novel flame retardant [9,10‐Dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxideÔtriphosphazene (DOPO–TPN)] based on phosphaphenanthrene and cyclotriphosphazene was synthesized and used to improve the flame retardancy of poly(ethylene terephthalate) (PET). The structure of DOPO–TPN was characterized by nuclear magnetic resonance, Fourier transform infrared spectroscope (FTIR), and elemental analysis. PET/DOPO–TPN composites with different amount of DOPO–TPN were prepared and the flame retardancy was determined by limiting oxygen index (LOI) and vertical burning test (UL‐94). With the incorporation of 5 wt % DOPO–TPN, the composite achieved a LOI value of 34% and UL‐94 V‐0 rating. The thermal properties of the PET/DOPO–TPN composites were investigated by thermogravimetric analysis. The flame retardant mechanism was investigated by pyrolysis‐gas chromatography/mass spectrometry (Py‐GC/MS), FTIR, and scanning electron microscopy (SEM). The Py‐GC/MS results showed that DOPO based fragments would exist in the gas phase during the pyrolysis of PET/DOPO–TPN composites which demonstrated that DOPO–TPN could act through gas‐phase action to exert flame retardant effect. The results of FTIR and SEM demonstrated that DOPO–TPN could promote the formation of compact and intact char residues to inhibit the heat and combustible gas transmission in condensed phase. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45246.     

Flame‐retardant behavior of a phosphorus/silicon compound on polycarbonate

A phosphorus/silicon flame retardant, MVC‐DOPO, was synthesized from 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) and 2,4,6,8‐tetra‐methyl‐2,4,6,8‐tetra‐vinyl‐cyclo‐tetrasiloxane (MVC) via addition reaction. Its flame‐retardant effect on polycarbonate (PC) was investigated. The phosphorus/silicon flame retardant increased the limited oxygen index and UL‐94 rating and reduced the heat release rate and total heat release of DOPO‐MVC/PC composites during combustion, indicating the excellent flame‐retardant effect of MVC‐DOPO on PC. MVC‐DOPO inhibited the burning intensity of PC material in the gaseous phase and promoted the formation of a more viscous residue in the condensed phase. Through releasing phosphorus‐containing pieces and phenoxy radicals from the phosphaphenanthrene group, MVC‐DOPO quenched the combustion chain reaction in the gaseous phase; through promoting formation of a more viscous residue and a dense char layer from the main actions of the cyclotetrasiloxane group, MVC‐DOPO reduced fuel release and generated a barrier effect in the condensed phase. Hence, MVC‐DOPO effectively exerted a flame‐retardant effect on PC material in both the gaseous and condensed phases during combustion. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45815.     

Phosphorus‐containing terephthaldialdehyde adducts—Structure determination and their application as flame retardants in epoxy resins

Two novel phosphorus‐rich prepolymers based on epoxy novolac and terephthaldialdehyde and potential flame retardants, 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) and 2,8‐dimethyl‐phenoxaphosphin‐10‐oxide (DPPO) were synthesised. The resultant flame‐retardant epoxy resins were cured with 4,4′‐diaminodiphenylmethane (DDM) and 4,4′‐diamino‐dicyclohexylmethane (PACM). Their flammability and burning behavior were characterised by UL 94 and LOI and compared with analogue prepolymers based on diethylphosphite (DEPP). The glass transition temperatures were determined by DSC measurements. Furthermore, the structures of two exemplary molecules based on p‐tolylaldehyde adducts were examined by XRD and NMR analysis to determine the possibilities of linking the two novel DOPO and DPPO derivatives to the backbone of the epoxy resin. Additionally, the char yields were determined by TG analysis and thermal desorption mass spectroscopy of the thermosets used and compared with each other to obtain more information about the possible mode of flame‐retardant action of the different phosphorus compounds. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis,thermal and mechanical behavior of a silicon/phosphorus containing epoxy resin

A liquid silicon/phosphorus containing flame retardant (DOPO–TVS) was synthesized with 9,10‐dihydro‐9‐oxa‐10‐phosphapheanthrene‐10‐oxid (DOPO) and triethoxyvinylsilane (TVS). Meanwhile, a modified epoxy resin (IPTS–EP) was prepared by grafting isocyanate propyl triethoxysilane (IPTS) to the side chain of bisphenol A epoxy resin (EP) through radical polymerization. Finally, the flame retardant (DOPO–TVS) was incorporated into the modified epoxy resin (IPTS–EP) through sol–gel reaction between the ethyoxyl of the two intermediates to obtain the silicon/phosphorus containing epoxy resin. The molecular structures of DOPO–TVS, IPTS–EP and the final modified epoxy resin were confirmed by FTIR spectra and ¹H‐NMR, ³¹P‐NMR. Thermogravimetric analysis (TGA), differential scanning calorimetry, and limiting oxygen index were conducted to explore the thermal properties and flame retardancy of the synthesized epoxy resin. The thermal behavior and flame retardancy were improved. After heating to 600°C in a tube furnace, the char residue of the modified resin containing 10 wt % DOPO–TVS displayed more stable feature compared to that of pure EP, which was observed both by visual inspection and scanning electron microscope (SEM). Moreover, the mechanical performance testing results exhibited the modified epoxy resins possessed elevated tensile properties and fracture toughness which is supported by SEM observation of the tensile fracture section. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42788.     

Flame retardancy effects of phosphorus‐containing compounds and cationic photoinitiators on photopolymerized cycloaliphatic epoxy resins

This study presents a promising ultraviolet (UV)‐curable epoxy resin formulation with improved flame‐retardant properties. The formulation is based on the cycloaliphatic epoxide 3,4‐epoxycyclohexylmethyl‐3,4‐epoxycyclohexane carboxylate (ERL4221) and a novel silicon, phosphorous containing flame‐retardant additive. The additive, 1,3,5,7‐tetramethyl‐1,3,5,7‐tetra 2‐(6‐oxido‐6‐H‐dibenzo(c,e) (1,2)oxaphosphorin‐6‐yl) ethylcyclotetrasiloxane (DOPO‐SiD), was synthesized by the addition reaction of 1,3,5,7‐tetramethyl‐1,3,5,7‐tetravinylcyclotetrasiloxane (D₄Vi) with 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO). Formulations containing the cycloaliphatic epoxy resin ERL4221 and the flame‐retardant DOPO‐SiD additive were prepared in various concentrations and crosslinked by UV irradiation. The effects of DOPO‐SiD and photoinitiators, such as the cyclopentadienyl iron complex of carbazole (In‐Fe) and diphenyl‐(4‐(phenylthiol) phenyl) sulfonium hexafluorophosphate (In‐S), on the flame‐retardant properties and thermal stabilities of UV‐cured ERL4221/DOPO‐SiD composites were investigated with limiting oxygen index, UL‐94 vertical test, and thermogravimetric analysis, respectively. The results showed that DOPO‐SiD can increase the thermal stabilities of the ERL4221/DOPO‐SiD. The char yield was improved when DOPO‐SiD and In‐Fe were simultaneously used. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40011.     

Studies on the formation of novel copolyesters containing naphthalene and aralkyloxy structures

Copolyesters containing naphthalene structure were synthesized from bis(hydroxyethyl)naphthalate (BHEN) and various aralkyloxy diols. The starting bis(4-(2-hydroxyethoxy)aryl) compounds were derived from a nucleophilic substitution of various bisphenols with ethylene carbonate in the presence of potassium iodide (KI). Copolyesters having intrinsic viscosities of 0.50 to 0.60 dL/g were obtained by melt polycondensation in the presence of metallic catalysts. The effects of reaction temperature and time on the formation of copolyesters were investigated in order to obtain an optimum condition for copolyester manufacturing. The optimal reaction temperature and time were found to be 290 to 310°C and 90 to 120 min, respectively. Most of these copolyesters have better solubilities than polyethylene naphthalate (PEN) in aprotic solvents such as N-methyl-2-pyrrolidone or m-cresol. The thermal properties of the copolyesters were investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Glass transition temperatures of these copolyesters were in the range of 90 to 141°C, and 10% weight loss values in nitrogen were all above 460°C. © 1995 John Wiley & Sons, Inc.     

Chemical modification of alkyd resin by a DOPO derivative and its flame retardancy

9,10‐Dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) and its derivatives have been widely used as effective flame retardants. In this study, 6‐((bis(2‐hydroxyethyl) amino) methyl)‐6H‐dibe‐nzo[c,e][1,2]oxaphosphinine‐6‐oxide (DHDOPO) was synthesized from DOPO, paraformaldehyde, and diethanolamine, and subsequently used as a reactant for synthesis of flame retarded alkyd resin (FR‐ALK). Thermogravimetric analysis (TGA) showed that DHDOPO had relatively high thermal stability and would not decompose at synthesis temperature of ALK. The thermal stability and flame retardancy of ALKs were improved by introduction of DHDOPO. As the mass fraction of phosphorus in FR‐ALK increased the decomposition temperature, the char yield in TGA experiments, the fire residue, and time to ignition in cone calorimeter tests increased, and peak heat release rate (PHRR) and total heat release (THR) decreased. Compared with the non‐flame retarded ALK the PHRR and THR values of FR‐ALK containing 2.5 wt % phosphorus decreased, respectively, by 43.1% and 58.5%. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45643.     

磷系阻燃改性共聚酯的热性能研究

选用主链含磷的阻燃剂2-羧乙基苯基次膦酸和侧链含磷的阻燃剂9,10-二氢-9-氧杂-10-[2,3-二(2-羟基乙氧基)羰基丙基]-10-磷杂菲-10-氧化物,在3 L聚合反应釜上分别合成了磷质量分数为0.6%的阻燃改性共聚酯。利用TGA、DSC对其热性能进行了分析,并对其切片干燥和熔融后的黏度降进行了测试。结果表明,随着反应型阻燃剂的添加,阻燃共聚酯的tg,tm下降,而Δt热和Δt冷则呈上升趋势,结晶能力下降;共聚酯的初始热分解温度有所下降,经切片干燥和熔融后的黏度降增大。     

Compatibilizers based on polypropylene grafted with itaconic acid derivatives. Effect on polypropylene/polyethylene terephthalate blends

New types of compatibilizers based on functionalized polypropylene (PP) were synthesized by radical melt grafting either with monomethyl itaconate or dimethyl itaconate. The effect of these new modified PP compounds were tested as compatibilizers in PP/polyethylene terephthalate (PET) blends. Blends with compositions 15/85 and 30/70 by weight of PP and PET were prepared in a single‐screw extruder. Morphology of the compatibilized blends revealed a very fine and uniform dispersion of the PP phase as compared with that of noncompatibilized blends of the same composition, leading to improved adhesion between the two phases. Whereas dimethyl itaconate derived agent showed less activity, the monomethyl itaconate parent compound showed an increase of the impact resistance of PET in PP/PET blend. This was attributed to the hydrophilic nature of the monomethyl itaconate part of this compatibilizer. The tensile strength of PET in noncompatibilized blends gradually decreases as the PP content increases, while blends containing functionalized PP exhibited higher values.     

Synthesis of a heat‐resistant DOPO derivative and its application as flame‐retardant in engineering plastics

A star‐shaped DOPO derivative (GL‐3DOPO, P content 10.8 wt %) was synthesized through a two‐step reaction involving glycerol, acryloyl chloride, and DOPO. The derivative demonstrated a great improvement of thermal decomposition temperature increased to 360 °C from 194 °C (under N₂ atmosphere), promoting its application in thermoplastics of high processing temperature. When blended with engineering plastics including PET, PBT, PC, PA6, and PA66 at a GL‐3DOPO loading of 25 wt %, all the compounds reached the UL94 V‐0 level and increased limit oxygen index (LOI). In PET system, LOI raised from 22.8% to 35.4% with P 2.5 wt % and passed the V‐0 test with only 0.8 P wt %. Compact char layers were found in the PET system after LOI test, suggesting that GL‐3DOPO acted both in gas and condensed‐phase mode. All results indicated that GL‐3DOPO could be a potential flame‐retardant for engineering plastics. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44892.