聚合物成炭阻燃新进展

根据协效阻燃、硅氧烷阻燃、聚合物纳米阻燃和本质阻燃的方法和机理综述了聚合物阻燃在成炭方面的研究新进展。提高与聚合物基体的相容性、降低聚合物材料的性能损失、提高聚合物的成炭阻燃效率、兼顾对环境友好已成为聚合物阻燃的研究重点。综合使用多种阻燃方法正成为聚合物阻燃的研究方向。     

Synthesis,Properties and Applications of Biodegradable Polymers Derived from Diols and Dicarboxylic Acids: From Polyesters to Poly(ester amide)s

Poly(alkylene dicarboxylate)s constitute a family of biodegradable polymers with increasing interest for both commodity and speciality applications. Most of these polymers can be prepared from biobased diols and dicarboxylic acids such as 1,4-butanediol, succinic acid and carbohydrates. This review provides a current status report concerning synthesis, biodegradation and applications of a series of polymers that cover a wide range of properties, namely, materials from elastomeric to rigid characteristics that are suitable for applications such as hydrogels, soft tissue engineering, drug delivery systems and liquid crystals. Finally, the incorporation of aromatic units and α-amino acids is considered since stiffness of molecular chains and intermolecular interactions can be drastically changed. In fact, poly(ester amide)s derived from naturally occurring amino acids offer great possibilities as biodegradable materials for biomedical applications which are also extensively discussed.     

Development of value-added polyethylene grades with extended service lifetime: Weathering resistant flame retarded materials for outdoor applications

The current article deals with the development of different novel, tailor-made polyolefin formulations exhibiting both low flammability and high weathering resistance, so as to provide value-added polyethylene grades with extended service lifetime. Two low-density (LDPE) and one linear low-density (LLDPE) polyethylene grades were modified via melt compounding with an additive system comprising: (a) a nitrogen-phosphorous intumescent system for flame retardance and (b) a hindered amine light stabilizer and a benzophenone-type UV absorber for UV/heat stabilization, at a total loading of 30–35 wt%. The target was to reach V0 classification in UL94V flammability tests, while to a large extent maintaining the mechanical properties, such as, tensile and impact strength of the investigated polymers, thus ensuring that the additives do not interfere significantly with the material quality. Subsequently, the compounds were subjected to separate artificial UV and heat aging at 100°C for 1500 h; the formulations showed good flame retardance, even after prolonged artificial weathering, but there was an observable, although acceptable, decrease in the mechanical properties. Nevertheless, all the results show that the developed polyethylene compounds are very promising for outdoor applications, such as, irrigation piping and profiles, where long-term weathering stability is important, and where flame retardance is important for safety during storage.     

Biocatalyic synthesis of unusually photoluminescent oligomers and electrically conducting polymers of 4‐(3‐pyrrolyl)butyric acid

Unusually photoluminescent undoped oligomers and doped electrically conducting polymers of 4‐(3‐Pyrrolyl)butyric acid have been enzymatically synthesized using the oxidoreductase soybean peroxidase as a catalyst. This biocatalytic approach provides a direct route to a fluorescent‐undoped oligomer of pyrrole that requires no protection/deprotection chemistry. The synthesis is carried out in aqueous media that requires only monomer, enzyme, and hydrogen peroxide. The undoped oligomer exhibits stable emission properties and is highly sensitive to the presence of environmentally important metal ions, such as Co(II), Hg(II), and Cu(II) in solution. Electrically conducting polymers can also be obtained by adding a dopant to a buffered reaction solution prior to initiating the polymerization. Polymers doped with camphor‐10‐sulfonic acid exhibit conductivity values as high as 10^?2 S/cm. Additionally, polymers synthesized in the presence of a biobased cationic template, N,N,N‐trimethylchitosan chloride, exhibit conductivity values that are an order of magnitude greater than polymers synthesized with the anionic polymeric template, poly(styrene sulfonic acid)‐sodium salt. The biobased synthetic strategy described here is the first report of directly obtaining an undoped, fluorescent conjugated oligomer of a pyrrole in aqueous solution. Unlike conventional chemical catalysts, the enzyme does not dope the oligomer and therefore provides the opportunity to directly obtain fluorescent conjugated species. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41035.     

Enhancing flame retardancy and optical functionality in multifunctional devices through advanced design of phosphorus-containing copoly(imide-oxadiazole)s

The combination of flame retardance and optical functionality in phosphorus-containing copoly(imide-oxadiazole)s offers a remarkable opportunity for the development of advanced and multifunctional devices, including organic light-emitting diodes, sensors, and photovoltaics. In this context, a series of phosphorus-containing copoly(imide-oxadiazole)s were synthesized through a polycondensation reaction. This involved an aromatic commercial dianhydride, 4,4′-(4,4′-isopropylidenediphenoxy)bis(phthalic anhydride), a diamine with phosphorus in the main and side chains, and various aromatic diamines with 1,3,4-oxadiazole rings. To achieve this, a solution imidization method was employed, which effectively converted the poly(amic acid) intermediates into the corresponding polyimides with high efficiency. The chemical structure and thermal properties of the resulting polymers were investigated. All polymers exhibited high thermal stability. Moreover, the absorption bands observed in dichloromethane, N,N-dimethylformamide, methanol, and N-methyl-2-pyrrolidone exhibited weak intensities, appearing as shoulders, with maximum values around 270, 303, and 310 nm. In most solvents, the photoluminescence spectra of the polymers showed a single emission band. However, one of the polymers exhibited two emission bands due to pendant groups that disrupted the molecular structure. The fluorescence of these derivatives was influenced by the polarity and proticity of the solvents. Furthermore, they exhibited large Stokes shifts, indicating extended conjugation and the potential to maximize luminescence efficiency. Protonation and deprotonation of polyimides alter their optical properties. These findings provide insights for the design of materials with improved optical performance.     

Preparation and properties of nadic‐end‐capped cyclotriphosphazene‐containing polyimide/carbon fiber composites

New novel fire‐resistant and heat‐resistant cyclotriphosphazene‐containing polyimide resins were prepared in situ by the polymerization of (p‐aminophenoxy)(phenoxy)cyclotriphosphazenes with 3,3′,4,4′‐benzophenonetetracarboxylic acid or 3,3′,4,4′‐diphenylsulfonetetracarboxylic acid and a crosslink agent, 5‐norbornene‐2,3‐dicarboxylic acid and were used as polymer matrix compositing with a woven carbon fiber to prepare nadic‐end‐capped cyclotriphosphazene‐containing polyimide/carbon fiber composites. The thermal stability, flame retardance, morphology of the surface fracture, and some physical properties of the composites were investigated by thermogravimetric analysis, scanning electron microscopy, and a material testing system, respectively. The composites had good thermal stability, flame retardance, and mechanical properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 810–818, 2003     

有机硅/聚合物阻燃改性应用与研究进展

介绍了有机硅/聚合物阻燃改性的应用和研究进展。通过有机硅对聚合物进行物理(共混)和化学改性(共聚、交联和接枝),聚合物的阻燃性能、加工性能、热稳定性和力学性能均得到改善。有机硅还和一些阻燃剂存在协效作用,能在阻燃材料中起到阻燃协效剂、加工助剂和分散剂的作用。     

Smoke suppressants for plasticized poly(vinyl chloride)

Addition of plasticizers to poly(vinyl chloride) generally increases its flammability and frequently increases smoke production during its burning. Flame retardants added to plasticized PVC can reduce flammability, but increase smoke production. This study shows that proper choice of combined use of other polymers, phosphate plasticizers, fillers and other flame retardants, produces measured synergistic improvements in flame retardance and smoke suppression which could benefit applications such as PVC wire and cable insulation.     

石墨烯阻燃聚合物的研究进展

综述了聚合物/石墨烯、聚合物/改性石墨烯和聚合物/石墨烯/阻燃剂的最新研究进展,介绍了石墨烯的阻燃机理,简介了石墨烯对聚合物力学性能的影响,并对石墨烯在阻燃性能上的发展前景进行了展望。     

Preparation and characterization of double-layered microencapsulated red phosphorus and its flame retardance in poly(lactic acid)

A novel double-layered microencapsulated red phosphorus (DMRP) has been prepared through chemical precipitation of aluminum trihydrate (ATH) and in situ polymerization of melamine formaldehyde (MF) resin on the red phosphorus (RP) powder surface, and its structure was characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The influence of DMRP on flame retardance and thermal stability of poly(lactic acid) (PLA) was thoroughly investigated by means of X-ray diffractometry (XRD), limiting oxygen index (LOI), vertical burning test, and thermogravimetric analysis (TGA). With an optimum mass ratio of RP/ATH/MF = 72.25%/12.75%/15%, it has been found that PLA with the addition of DMRP at 25 wt % loading level shows good flame retardance compared to plain RP as well as the conventional microencapsulated red phosphorus (CMRP), and can achieve UL94 V-0 rating along with an LOI increase from 20.5 to 29.3. The TGA and XRD studies indicate that the interaction occurs among all three components: RP, ATH, and MF resin. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

改性PP三元共混体阻燃性能的研究

研究了含卤阻燃剂，十溴联苯醚（ＤＢＤＰＯ）；氯化聚乙烯（ＣＰＥ）和三氧化二锑（Ｓｂ２Ｏ３）及氢氧化铝对改性聚丙烯（ＰＰ）－聚丙烯／高密度聚乙烯／乙丙橡胶（ＰＰ／ＨＤＰＥ／ＥＰＲ）三元共混体阻燃性能的影响，分析了阻燃剂间的协同作用，讨论了阻燃机理，结果表明：（１）Ｓｂ２Ｏ３与ＤＢＤＰＯ、ＣＰＥ并用能改性ＰＰ三元共混体的阻燃性能提高，当含卤阻燃剂用量是Ｓｂ２Ｏ３的四倍左右时阻燃效果最好，阻燃性能提高一     

以三氧化二锑为协效剂的复合阻燃剂对MVQ硫化胶阻燃性能的影响

分别研究硼酸锌／三氧化二锑、氢氧化铝／三氧化二锑和三氧化钼／三氧化二锑并用体系对甲基乙烯基硅橡胶(MVQ)硫化胶阻燃性能和物理性能的影响。结果表明，硼酸锌／三氧化二锑并用体系可有效提高MVQ硫化胶的阻燃性能，并能保持较好的物理性能；氢氧化铝／三氧化二锑并用体系的阻燃效果十分显著，但MVQ硫化胶的发烟量稍大；三氧化钼／三氧化二锑并用体系虽可减小MVQ硫化胶的发烟量，但阻燃效果不明显，且硫化胶的物理性能受损严重。     

阻燃剂N,N’-乙撑双四溴邻苯二甲酰亚胺的合成及应用研究

以邻苯二甲酸酐和乙二胺为原料,水作介质,先制得中间体N,N’-乙撑双邻苯二甲酰亚胺,然后经溴代合成出白色阻燃剂N,N’-乙撑双四溴邻苯二甲酰亚胺,并通过聚丙烯测定了产物的阻燃性能。结果表明,较佳工艺条件为:中间体5 g,溴14 g,浓度20%的发烟硫酸80 mL,150℃反应8 h,产率90%,产物的溴含量66.4%接近理论值,外观呈白色,总产率87%。当添加量为15%时,阻燃聚丙烯的LOI值达到28%,阻燃等级达到UL94-V0级别。     

Interpenetrating polymer network of blocked polyurethane and phenolic resin. II. Kinetic formation,swelling ratio,thermal properties,and flame retardance

Blocked polyurethane (BPU)/phenolic (PF) interpenetrating polymer network (IPN) were prepared from BPU prepolymer with m‐xylylenediamine (MXDA) as a chain extender and PF prepolymer using p‐toluene sulfonic acid (PTSA) as a catalyst. The kinetic aspects of the formation of a second network in the presence of the first have been studied in BPU/PF IPN. The effect on kinetics of parameters such as the BPU content and the reaction temperature has been examined. The studies of swelling ratio, thermal properties, and flame retardance of IPN are based on BPU content and filler content. Results showed that the swelling ratio of IPN increased with the increasing of BPU content, and decreased with the increasing of filler (kaolin) content. The IPN possesses good thermal properties of weight loss and thermal degraded temperature by thermogravimetric analysis (TGA) test when the IPN decreased the BPU content and increased the filler (kaolin) content. The IPN showed the excellent flame retardance when the IPN decreased the BPU content. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

聚乳酸阻燃改性研究进展

综述了近年来国内外聚乳酸( PLA)阻燃改性的研究进展,对磷系、氮系、硅系、膨胀型阻燃体系,无机及纳米粉体等各种环保型阻燃体系在PLA中的应用情况进行探讨,并对未来的发展趋势进行了展望.     

Acidic buffer mechanism of cyclotriphosphazene and melamine cyanurate synergism system flame retardant epoxy resin

In this research, a new synergistic mechanism based on an acid‐buffer action for cyclotriphosphazene (CPZ)/melamine cyanurate (MCA) flame retardant epoxy resin (EP) was proposed. This mechanism broke through the conventional well‐recognized phosphorus–nitrogen interaction one. It revealed that CPZ had not only acid‐catalytic charring but also acid‐catalytic degrading effect on EP. The former that occurs in higher temperature range to improve the flame resistance in the condensed phase is a mechanism generally accepted for the phosphorus flame retardant, but the later that occurs in lower temperature range to deteriorate the flame retardance is usually ignored by the people. For CPZ/MCA flame retardant EP, the produced organic base from decomposed MCA can neutralize the acids from CPZ. Decline of the acidity effectively weakened the acid‐catalytic effect, and reduced the volatiles release rate of the degraded resin in the initial stage, thus slowing down the combustion in the gaseous phase. With increasing temperature, the neutralized products were converted to the phosphorus‐containing acids again to promote the formation of the chars. A series of characterizations such as vertical burning test, X‐ray photoelectron spectra, micro‐scale combustion calorimetry, thermogravimetric, and differential thermogravimetric analysis of the flame retardant materials and the pH value detection of the corresponding carbonation products were performed to investigate the acid‐buffer mechanism. The experimental results including no N? P forms in the condensed phase obviously improved flame retardance and increased degradation temperature of CPZ/MCA/EP compared with CPZ/EP, as well as the enhanced pH value of the former carbonation residue confirmed the above mechanism. POLYM. ENG. SCI., 55:1046–1051, 2015. © 2014 Society of Plastics Engineers     

Effect of sulfur in different valence on flame retardance of epoxy resin for light emitting diode

A novel phosphorus/nitrogen-containing flame retardant (DOPO-AM) was synthesized by 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and acrylamide (AM) and its chemical structure was characterized. DOPO-AM was added into diglycidyl ether of bisphenol-A (DGEBA) with curing agent m-xylylenediamine (MXDA)to prepare flame retarded epoxy resin to reduce the possibility of fire. The compounds with different valences sulfur respectively replace partial DGEBA resin to study the effects of sulfur valences on the flame retardance of epoxy resins. The results indicated that DOPO-AM had excellent flame retardance for epoxy resin. When phosphorus content was only 0.75%, DGEBS resin containing DOPO-AM achieved the limiting oxygen index value of 34.55% and vertical burning test (UL-94) V-0 rating. Although sulfur element is help for refractive index of epoxy resin, sulfur element in three kinds of valences all weaken the flame retardant of epoxy resin. Improving phosphorus content is help for the synergistic effect of P N and P N S. Moreover, the flame retardance is not proportional to sulfur valence, sulfide with +2 valence had the best flame retardance. However, +6 valence sulfonic with strong oxidation effect worsen the flame retardant. Simultaneous thermal analysis of thermogravimetric analyzer and differential scanning calorimeter and scanning electronic microscopy photographs verified the above conclusion.     

Preparation of novel dendritic flame‐retardant polymer and its application in EPDM composites

Flame‐retardant polymer, dendritic tetramethylolphosphonium chloride (FR‐DTHPC), was prepared by condensation polymerization between THPC, the monomer we prepared, and boric acid. It was then characterized by Fourier transform infrared spectroscopy, intrinsic viscosity, and matrix assisted laser desorption ionization time of flight mass spectrometer. This FR‐DTHPC was used in the preparation of flame‐retardant ethylene propylene diene monomer (EPDM) composites. Different types of EPDM/FR‐DTHPC composites were prepared with different amounts of FR‐DTHPC. Then, the cure characteristic, tensile properties, flame‐retardance, and thermal stability were researched and compared. Results showed that the addition of this novel additive can improve some mechanical and flame‐retardant properties of EPDM composites. Mechanisms of reinforcing and flame‐retardance were proposed. The dendritic polymer may reduce the amount and size of voids in EPDM composites, and thus may increase their tensile properties. Meanwhile, the degradation products from nitrogen, phosphorus, and boric acid in FR‐DTHPC can increase the amount of carbonaceous layers, and thus can inhibit the pyrolysis degree of EPDM composites during burning and improve their flame‐retardant performance. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40855.     

Synthesis and properties of novel flame‐retardant poly(amide‐imide)s containing phosphine oxide moieties in main chain by microwave irradiation

Eight new flame‐retardant poly(amide‐imide)s with high inherent viscosities containing phosphine oxide moieties in main chain were synthesized from the polycondensation reaction of N,N′‐(3,3′‐diphenylphenylphosphine oxide) bistrimellitimide diacid chloride 7, with eight ;aromatic diamine 8a–h by two different methods such as solution and microwave‐assisted polycondensation. Results showed that the microwave‐assisted polycondensation by using a domestic microwave oven proceeded rapidly, compared with solution polycondensation and were completed within about 10–12 min. The resulting poly(amide‐imide)s 9a–h showed high thermal stability and flame‐retardant properties. All of the obtained polymers were fully characterized by means of elemental analysis, viscosity measurements, solubility test, and FTIR spectroscopy. Thermal properties of the PAIs 9a–h were investigated by using thermal gravimetric analysis (TGA), derivative thermogravimetric analysis (DTG), and differential scanning calorimetry (DSC). Char yield measurements at 600°C demonstrated that incorporating phosphine oxide moieties in polymer backbone markedly improves their flame retardancy. All of the earlier polymers were soluble at room temperature in various organic solvents such as NMP, DMF, DMSO, DMAc, and concentrated sulfuric acid. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4263–4269, 2006     

Synthesis and characterization of new flame‐retardant poly(amide‐imide)s containing phosphine oxide and hydantoin moieties in the main chain

Six new flame‐retardant poly(amide‐imide)s (PAIs) 9a–f with high inherent viscosities containing phosphine oxide and hydantoin moieties in main chain were synthesized from the polycondensation reaction of N,N′‐(3,3′‐diphenylphenylphosphine oxide) bistrimellitimide diacid chloride 7 with six hydantoin derivatives 8a–f by two different methods such as solution and microwave assisted polycondensation. Results showed that the microwave assisted polycondensation, by using a domestic microwave oven, proceeded rapidly, compared with solution polycondensation, and was completed in about 7–9 min. All of the obtained polymers were fully characterized by means of elemental analysis, viscosity measurements, solubility test, and FTIR spectroscopy. Thermal properties and flame retardant behavior of the PAIs 9a–f were investigated using thermal gravimetric analysis (TGA and DTG) and limited Oxygen index (LOI). Data obtained by thermal analysis (TGA and DTG) revealed that these polymers showed good thermal stability. Furthermore, high char yields in TGA and good LOI values indicated that these polymers are capable of exhibiting good flame retardant properties. These polymers can be potentially utilized in flame retardant thermoplastic materials. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5062–5071, 2006