Block copolymers of unsaturated polyesters and functional elastomers

Block copolymers of unsaturated polyester were prepared by condensation polymerization of hydroxyl or carboxyl terminated liquid rubbers with maleic anhydride, phthalic anhydride, and propylene glycol. The condensate obtained was mixed with styrene monomer to get an unsaturated polyester resin formulation. In this study, copolymers of unsaturated polyesters with hydroxy terminated polybutadiene, carboxy terminated nitrile rubber, and hydroxy terminated natural rubber were prepared. Mechanical properties such as tensile strength, tensile modulus, elongation at break, toughness, impact strength, surface hardness, abrasion resistance, and water absorption were evaluated after the resin was cured in appropriate molds for comparison with the control resin. The fracture toughness and impact resistance of CTBN‐modified unsaturated polyester show substantial improvement by this copolymerization without seriously affecting any other property. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1956–1964, 2004     

SYNTHESIS OF UNSATURATED POLYESTER RESIN—EFFECT OF CHOICE OF REACTANTS AND THEIR RELATIVE PROPORTIONS

Unsaturated polyesters are synthesized in the laboratory by the condensation of saturated and unsaturated anhydrides with glycols. The condensate obtained is mixed with styrene monomer to get an unsaturated polyester resin formulation. The properties of the polyester resin synthesized are affected by the synthesis parameters. In this study, the parameters investigated are the effect of choice of reactants and their relative proportions. Properties such as tensile strength, tensile modulus, elongation-at-break, toughness, impact strength, surface hardness, abrasion resistance, and water absorption were tested after curing the resin. Various combinations of (a) maleic anhydride and phthalic anhydride, (b) propylene glycol and ethylene glycol, and (c) propylene glycol and diethylene glycol were used to investigate the effect on the properties of the synthesized resin. The combinations of the anhydrides and glycols that give optimum properties are identified. The results show that most of the properties are maximum at 60% maleic anhydride composition in a mixture of maleic anhydride and phthalic anhydride. Similarly, a better balance of properties is obtained when propylene glycol is mixed with 30% ethylene glycol or 20% diethylene glycol.     

基于二聚脂肪酸改性苯乙烯聚酯树脂的合成及性能

以C₃₆二聚脂肪酸、邻苯二甲酸酐、顺丁烯二酸酐和1,2-丙二醇为原料合成不饱和聚酯树脂（UPR）。以苯乙烯为交联剂、过氧化苯甲酰为引发剂,固化后得到C₃₆二聚脂肪酸（DFA）改性苯乙烯聚酯树脂。采用FT-IR和SEM表征树脂结构及拉伸断面形貌,研究发现DFA引入树脂主链且发生反应,树脂断裂方式由脆性断裂转变为韧性断裂。通过TG、DSC、拉伸、弯曲、硬度和耐溶剂实验研究了DFA用量对树脂热稳定性、力学性能和耐溶剂性能的影响。当DFA含量为6%（摩尔分数）时,改性UPR材料的综合性能最佳,初始热分解温度由147℃增加到201℃,玻璃化转变温度由146.6℃降低到120.7℃,拉伸强度、断裂伸长率、弹性模量、邵氏硬度、弯曲强度分别是未改性树脂的7.23、2.90、7.84、1.63、5.12倍,而且耐溶剂损失率均降低70%以上。DFA可以改善苯乙烯聚酯树脂的柔韧性,是一种有效的增韧改性剂。     

Synthesis of Unsaturated Polyester Resin—Effect of Sequence of Addition of Reactants

Abstract

Unsaturated polyesters were synthesized in the laboratory by the condensation of maleic anhydride and phthalic anhydride with propylene glycol. The condensate obtained was mixed with styrene monomer to get an unsaturated polyester resin formulation. The properties of the polyester resin synthesized were found to be affected by the synthesis parameters. In this study, the effect of sequence of addition of reactants on the properties of resin was investigated. Properties such as tensile strength, tensile modulus, elongation at break, toughness, impact strength, surface hardness, abrasion resistance, and water absorption were evaluated after curing the resin. Propylene glycol necessary for esterification of both the anhydride fractions was initially reacted with phthalic anhydride. Later, the esterification was completed by reaction with maleic anhydride. This sequence of addition of reactants was found to give the best mechanical properties among all possible methods of reactant addition. Moreover, it was found that this sequence of addition of reactants gives the shortest reaction time.     

Modification of unsaturated polyester resin by polyurethane prepolymers

Unsaturated polyester resins (UPRs) are extensively used by the fiber‐reinforced plastic (FRPs) industry. These resins have the disadvantages of brittleness and poor resistance to crack propagation. In this study, UPRs were chemically modified by reactive blending with polyurethane prepolymers having terminal isocyanate groups. Hybrid networks were formed by copolymerisation of unsaturated polyesters with styrene and simultaneous reaction between terminal hydroxyl groups of unsaturated polyester and isocyanate groups of polyurethane prepolymer. The prepolymers were based on toluene diisocyanate (TDI) and each of hydroxy‐terminated natural rubber (HTNR), hydroxy‐terminated polybutadiene (HTPB), polyethylene glycol (PEG), and castor oil. Properties like tensile strength, toughness, impact resistance, and elongation‐at‐break of the modified UPRs show considerable improvement by this modification. The thermal stability of the copolymer is also marginally better. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 449–456, 2006     

Effect of the modified silica Nanofiller on the Mechanical Properties of Unsaturated Polyester Resins Based on Recycled Polyethylene Terephthalate

Unsaturated polyester resin (UPe)‐based nanocomposites and fumed silica Aerosil R812S, R805 and R816, and R200 modified with phenyl terminal group, R200NPh, were prepared. UPe resins were synthesized from maleic anhydride and products of glycolysis, obtained by polyethylene terephthalate depolymerization with dipropylene glycol in the presence of tetrabutyl titanate catalyst. The obtained unsaturated polyesters were characterized by acid, hydroxyl, and iodine values and by FTIR and NMR analysis. The microstructural analysis of the prepared nanocomposites, performed by using transmission electron microscopy, confirmed that silica nanoparticles formed chain‐like aggregates in the polymer matrix. The presence of modified silica nanoparticles had no influence on the glass transition temperature and thermal stability of polyester matrix. The tensile modulus, stress at break, and hardness of cured products increased with increasing silica content. The impact strength of cured samples was not influenced by the silica content. POLYM. COMPOS., 38:538–554, 2017. © 2015 Society of Plastics Engineers     

MFE乙烯基酯树脂的增韧研究

采用有机改性膨润土和聚乙二醇与乙烯基酯树脂复合成功制得纳米复合材料,在保持树脂拉伸、弯曲强度的同时,树脂的断裂伸长率和耐冲击性能得到了大幅度的改善。有机膨润土和聚乙二醇含质量分数为4%和15%,冲击强度为7．58 MPa,断裂伸长率为8．99%。     

高强度高伸长率聚氨酯改性不饱和聚酯

利用聚氨酯改性的方法合成了一种新型不饱和聚酯，该树脂可以室温固化，固化后拉伸强度达20MPa、断裂伸长率高达100％以上，可用于制作柔韧性要求较高的制品，亦可以加入其它树脂中，提高材料的冲击性能和断裂伸长率。     

Unsaturated polyester based on poly(ethylene glycol)

Unsaturated polyesters were prepared by one-stage melt condensation of maleic anhydride, phthalic anhydride, propylene glycol, and poly(ethylene glycol)s with different molecular weight, and the properties of their castings from styrenated resins were investigated. Tensile and flexural properties decrease with the increase of molecular weight of poly(ethylene glycol), but impact strength, elongation, and water absorption have an inverse effect. This study improves the understanding of the effect of chain length of poly(ethylene glycol) in unsaturated polyester on the properties of its castings.     

Unsaturated polyesters based on bis(2-hydroxyethyl)terephthalate

A series of unsaturated polyesters based on bis(2-hydroxyethyl)terephthalate, ethylene glycol, propylene glycol, diethylene glycol, maleic anhydride and styrene were prepared. Properties of these castings were investigated and compared with those analogues based on dimethyl terephthalate or polyester oligomers formed by depolymerization of poly(ethylene terephthalate). It is found that properties of castings based on bis(2-hydroxyethyl)terephthalate are superior to those based on polyester oligomer. When compared with those based on dimethyl phthalate, the castings have higher hardness and heat distortion temperature, but lower tensile strength and elongation; other properties are very similar.     

具有高伸长率的二异氰酸酯改性不饱和聚酯

介绍了1种新型二异氰酸酯改性不饱和聚酯,该树脂可以室温固化,固化后树脂的拉伸强度和断裂伸长率分别可达20 MPa和106%。该树脂可用于制作高柔韧性制品,亦可以加入到其他不饱和聚酯中,提高其冲击性能和断裂伸长率。     

Study on Mixed Glycols-based Semi-flexible Unsaturated Polyester Resins for Inhibition of Rocket Propellants

Seven semiflexible unsaturated polyester resins based on isophthalic acid, maleic anhydride and polyethylene glycol-200 and propylene glycol (in different proportions) have been synthesised and characterised for gel time, exotherm peak temperature, tensile strength, percentage elongation, bond strength, nitroglycerine absorption, water absorption, flame resistance and voltile losses. The effect of glycol variation on these properties has also been discussed. Based on the data for various characteristics, resin 4 has been selected for inhibition and static evaluation of propellant. The propellant sustainers containing 2 NDPA have been inhibited with resin 4 without the application of any barrier coats and statically fired at ambient, cold and hot temperatures. The results of the static firings prove the worthiness of the new direct bonding inhibition system.     

腰果酚接枝黄麻纤维不饱和聚酯复合材料的力学性能及界面调控

用甲苯二异氰酸酯与腰果酚(CNSL)合成大分子偶联剂接枝黄麻纤维。以接枝的黄麻纤维为增强体,通用的不饱和聚酯树脂为基体,采用热压方式制备复合材料。比较了纯饱和聚酯树脂、5 %CNSL增韧的不饱和聚酯树脂、25 %碱处理的黄麻纤维不饱和聚酯树脂复合材料和25 %的CNSL接枝黄麻纤维不饱和聚酯树脂复合材料的拉伸强度和冲击强度。结果表明,CNSL接枝于黄麻纤维上;CNSL的加入能提高材料的韧性,黄麻纤维能提高材料的拉伸强度而不能提高材料韧性;25 %CNSL接枝的黄麻纤维不饱和聚酯树脂能提高材料的拉伸强度和韧性,25 %CNSL接枝的黄麻纤维增强含5 %CNSL的不饱和聚酯复合材料,其冲击强度为12.10 kJ/m^2。     

多元醇与环氧树脂共混改性的研究

采用自制的聚酯多元醇对环氧树脂进行共混改性,对改性环氧树脂固化物的拉伸强度、断裂伸长率、冲击强度、剪切强度等进行了考察,同时探讨了多元醇分子量变化及加入量不同对性能的影响。结果表明,改性后的体系韧性得到了明显的提高,如冲击强度从13.2kJ/m2提高到26.3kJ/m2。室温剪切强度从24.2MPa提高到43.75MPa。     

丙烯酸酯改性不饱和聚酯的研究

普通不饱和聚酯树脂脆性大,故有必要对其进行增韧改性。本文合理选用丙烯酸酯对不饱和聚酯树脂进行增韧及其他性能改性,制备改性不饱和聚酯树脂。研究表明,随着丙烯酸丁酯（BA）的用量增加,不饱和聚酯的断裂伸长率、冲击强度增加;但不饱和树脂的弹性模量减小、拉伸强度急剧降低,当BA的用量为10%时,弹性模量减少至1.0 GPa左右;耐水分析表明树脂的耐水性能优良;DSC差热分析表明,改性树脂的Tg值在61℃左右,满足基本的使用要求。     

Toughened polyester matrices for advanced composites

An intercrosslinked network of hybrid bismaleimide (BMI) modified vinyl ester oligomer–unsaturated polyester matrix systems have been developed. Vinyl ester oligomer (VEO) was used as a toughening agent for unsaturated polyester resin and was added in 2, 4, and 6% (by wt). Benzoyl peroxide was used as curing agent. The VEO‐toughened unsaturated polyester matrix systems were further modified with 5, 10, and 15% (by wt) of bismaleimide. Bismaleimides modified vinyl ester–unsaturated polyester matrices were characterized by mechanical (tensile strength, flexural strength, tensile modulus, flexural modulus, and impact strength), thermal [differential scanning calorimetry (DSC), thermogravimetic analysis (TGA), heat deflection temperature analysis (HDT)] and morphological studies [scanning electron microscope (SEM)] and water absorption. Data obtained from mechanical studies indicated that the introduction of VEO into unsaturated polyester resin improves the fracture toughness. The introduction of BMI into VEO incorporated unsaturated polyester resin enhanced both thermal and mechanical behavior. The scanning electron micrographs of fractured surfaces of VEO‐modified unsaturated polyester systems and BMI modified vinyl ester–unsaturated polyester matrices illustrate the presence of homogeneous morphology. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 167–177, 2007     

端环氧基硅油改性环氧树脂性能研究

采用端环氧基硅油及其预反应物来改性双酚A型环氧树脂。采用热分析、扫描电镜和力学性能等测试方法系统探讨了改性方法、有机硅含量对环氧树脂性能的影响。采用端环氧基硅油直接物理共混改性的EP,其耐热性几乎不变,但力学性能下降较大。采用5份端环氧基硅油预反应物改性的EP,其玻璃化转变温度由未改性的163.23 ℃提高到165.90 ℃,拉伸强度几乎保持不变,断裂伸长率由7.6 %提高到16.7 %,冲击强度由20.23 kJ/m2提高到27.19 kJ/m2。拉伸断面的SEM照片表明,环氧树脂固化物显示出明显的增韧效果。     

Semi-interpenetrating polymer networds produced with polyethylene terephthalate oligomer and unsaturated polyester resin

A series of semi-interpenetrating polymer networks (semi-IPN's) based on different compositions of an acyclic polyethylene terephthalate oligomer and unsaturated polyester resin (UP) were prepared. The oligomer was dissolved in the resin containing styrene crosslinker. Later this mixture was crosslinked at room temperature using methyl ethyl ketone peroxide catalyst and cobalt naphtanate as promoter. The tensile strength of the IPN's decreases as the concentration of oligomer increases, whereas, elongation to break increases. A characterization of the oligomer used is also presented.     

桐油改性双环戊二烯不饱和树脂的合成研究

利用缩聚反应后期桐油与双环戊二烯不饱和聚酯(DCPD-UPR)主链上不饱和双键的Diels-Alder(D-A)反应合成了桐油改性DCPD-UPR,研究了各种原料用量对桐油改性DCPD-UPR其浇注体力学性能的影响。结果表明:当顺酐与苯酐的物质的量比为2∶1～3∶1,双环戊二烯与顺酐物质的量比为0.6～0.8∶1,1,2-丙二醇与二甘醇物质的量比2∶1,缩聚反应后期加入10%(质量分数)桐油,苯乙烯质量分数为35%～40%时,获得的桐油改性DCPD-UPR粘度适中,浇注体的断裂伸长率提高了78.2%,冲击强度提高了82.0%。     

Unsaturated Polyester Resins Obtained from Glycolysis Products of Waste PET

Abstract

Waste polyethylene terephthalate (PET) flakes were depolymerized by using ethylene glycol (EG), propylene glycol (PG), diethylene glycol (DEG), and triethylene glycol (TEG) in the presence of zinc acetate as catalyst. All glycolysis products were reacted with maleic anhydride and mixed with styrene monomer to get unsaturated polyester (UP) resins. Molecular weights of all synthesized UP resins were determined by end-group analysis. The curing characteristics such as gel time and maximum curing temperatures, and mechanical properties such as hardness, tensile strength, and elastic module of these resins were investigated. The waste PET resins were compared with the reference resins prepared with the same glycols and the properties of the resins were found to be compatible with the properties of the reference resins.