Effects of diacrylate monomers on the mechanical properties of polymer concrete made with wet aggregates

Because normal polymer concrete does not work well with wet aggregates, diacrylate (DA) monomers were evaluated for improving the mechanical properties of polymer concrete made with wet aggregates. Zinc diacrylate (ZDA) and calcium diacrylate (CDA) were each used as an additive to resins (two epoxies). The variables were the amount of diacrylate monomers and the aggregate conditions (wet or dry). Compressive strength, flexural strength, workability, working time, and curing time were measured. ZDA was found to improve the workability and the working time, and CDA was found to improve the compressive and the flexural strength. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1077–1085, 2004     

Moisture sensitivity of polyester and acrylic polymer concretes with metallic monomer powders

To evaluate the moisture sensitivity of polyester and acrylic polymer concretes with commercial metallic monomer powders, polymer concretes containing different levels of these powders were investigated with respect to the properties of hardened polymer concrete. The mix design was made and optimized for workability, strength, and economy, which depended on the resin viscosity, the intended use, and the additional quantities of the polymeric materials. The investigated properties included the compressive and flexural strengths of hardened polymer concrete. These polymeric materials offer the possibility of using wet aggregates in polyester and acrylic polymer concrete construction. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and properties of poly(acrylates-co-urethane) adhesives for low surface energy materials

The series of poly(acrylates-co-urethane) were synthesized based on the copolymerization between 2-hydroxyethyl acrylate terminated polyether (or polyester) urethane and acrylate monomers initiated by tri-n-butylborane (TBB). The effects of the soft segment of polyether (or polyester) urethane diacrylate on the copolymer properties were mainly discussed. Polyether (or polyester) urethane was relatively well dispersed in polyacrylate continuous phase, and was intended to aggregate with the increase of soft segment polarity and content. The adhesion to low surface energy materials and loss factor (tan δ) of copolymers were almost not influenced by the soft segment content, but decreased with the increase of soft segment polarity within the scope of the study. On the other hand, the working life of copolymers as adhesives was shortened with the increase of soft segment polarity, but prolonged with the increase of soft segment content. The copolymers with different structures of polyether (or polyester) urethane diacrylate were also shown to be good candidates as adhesives at room temperature.     

Stress–strain properties and thermal resistance of polyurethane–polyepoxide interpenetrating polymer networks

Two-component interpenetrating polymer networks (IPN) of the SIN type (simultaneous interpenetrating networks) were prepared from three different polyurethanes and two epoxies. The linear prepolymers were combined in solution, together with crosslinking agents and catalysts, films cast, and subsequently chain extended and crosslinked in situ. Two of the IPN's showed significant improvement in thermal resistance, as measured by thermogravimetric analysis (TGA). All of the IPN's showed maxima in tensile strength significantly higher than the tensile strengths of the component networks at 25% polyurethane and minima at 75% polyurethane. The minima were explained by an initial dilution of the strong polyurethane hydrogen bonds by the epoxies, and the maxima, by an increase in crosslink density due to interpenetration.     

两亲性苯甲酰甲酸酯类光引发剂及其引发性能

以苯甲酰甲酸和三乙二醇为原料合成了一种水油两亲性光引发剂苯甲酰甲酸三乙二醇单酯（TGBF），并利用紫外-可见分光光度计、电子自旋共振仪及实时红外光谱仪等手段探究了TGBF的光吸收性能、光降解机理、水中溶解性以及引发光聚合的能力。研究结果表明，TGBF在300 nm以上波长的摩尔消光系数较低，但在405 nm LED光源照射下，能够发生分子内或者分子间的夺氢反应，并产生烷基自由基引发单体聚合。TGBF具有良好的水溶性，可高效地引发油性单体三丙二醇二丙烯酸酯（TPGDA）与水性单体聚乙二醇400二丙烯酸酯（PEG（400）DA）的聚合，最终双键转化率可达到80%以上。更重要的是，TGBF具有优异的引发油性单体TPGDA与水性单体深度聚合的能力，聚合深度分别达到5.6cm和6.5 cm以上,在深层LED光聚合领域表现出极大的应用潜力。     

乳聚丁苯互穿网络型热塑性弹性体的制备

以丁苯胶乳为种子乳液,苯乙烯、甲基丙烯酸甲酯、丙烯腈或它们的混合物的硬单体,用氧化还原引发体系,经种子乳液聚合法同备出复合乳液,絮凝干燥后所得互穿聚合物网络可热塑性反复加工。考察了硬单体的种类和用量、交联剂的种类及用量、反复加工次数对聚合物力学性能的影响。用透射电子显微镜观察了乳胶粒微观形态,结果表明：用混合单体,聚合物力学性能较优,以３５份Ｓｔ＾＋ＭＭＡ为第二单体制备的聚合物的攫断伸长率为４００％,拉伸强度为９．３ＭＰａ,３００％定伸应力为７．６ＭＰ,撕裂强度为７３．９ｋＮ．Ｍ＾－１,邵尔Ａ型硬度为８４。     

Radiation vulcanization of natural rubber with polyfunctional monomers

This study presents the effect of the polyfunctional monomers (PFMs) triallylcyanurate (TAC), triallylisocyanurate (TAIC), trimethylolpropane trimethacrylate (TMPT), ethylene glycol dimethacrylate (EDMA) and zinc diacrylate (ZDA) on the mechanical properties of natural rubber (NR) crosslinked by electron beam (EB) processing. Dependence of mechanical properties and crosslink density on irradiation dose was determined from a dose range of 50 to 200 kGy. The control blends, obtained with benzoyl peroxide as curing agent, were prepared by blending on a laboratory roller and the control sample curing was accomplished on hydraulic press at 160 °C. The results showed an increase in mechanical properties and crosslink density due to the introduction of PFMs. Also, based on the comparison between EB irradiation and dibenzoyl peroxide vulcanization efficiency, the experimental results show that EB irradiation gave the best results.     

Modification of some mechanical properties of spruce by radiation induced copolymerization of acrylonitrile and methyl methacrylate with allyl glycidyl ether

In this study, spruce samples were impregnated with acrylonitrile (AN), methyl methacrylate (MMA), allyl glycidyl ether (AGE), AGE/AN or AGE/MMA monomers and monomer mixtures. In situ polymerization (copolymerization) was achieved by gamma irradiation. The relationship between the mechanical properties of the wood‐polymer(copolymer) composites and the kind and quantity of polymers and copolymers, irradiation dose and artificial aging treatment of the wood was investigated. The fine structure of wood‐polymer(copolymer) composites was determined by Scanning Electron Microscopy. The presence of homopolymer and copolymers increased the mechanical properties of the wood. The compressive strength and Brinell Hardness Numbers, determined for untreated and treated wood samples, indicated that the mechanical strength of wood‐polymer (copolyrner) was significantly increased in the presence of P(AGE/MMA). At maximum percent conversion, the percentage increase in the compressive strength with regard to the applied force perpendicular to the fibers in spruce was 218%. After aging for 28 days, it was found that there were no significant changes in mechanical stability.     

Improvement of the mechanical stability of oak by radiation-induced in-situ copolymerization of allyl glycidyl ether with acrylonitrile and methyl methacrylate

This study deals with the improvement of the mechanical stability of oak, which belongs to the hardwoods, by radiation-induced in-situ copolymerization of certain monomers. Acrylonitrile (AN), methyl methacrylate (MMA), allyl glycidyl ether/acrylonitrile (AGE/AN), and allyl glycidyl ether/methyl methacrylate (AGE/MMA) monomers and monomer mixtures were employed to conserve and consolidate the wood. After impregnating oak with these monomer mixtures, polymerization was accomplished by γ-irradiation. The relationships between the mechanical properties of the wood/(co)polymer composites and the anatomic structure of the wood, the types and the quantity of the polymer and copolymer, the irradiation dose and the aging process were explored. The fine structure of the wood/(co)polymer composites and the compatibility of wood with polymer and copolymer were investigated by scanning electron microscopy. The existence of polymer and copolymer in the wood enhanced the mechanical durability of the wood. The results of the hardness and the compressive strength tests applied in the parallel and perpendicular directions to the fibers of the wood/(co)polymer composites show that P(AGE/MMA), P(AGE/AN) copolymers are effective in raising the mechanical durability. In the case of P(AGE/MMA), the increase in the compressive strength perpendicular to the fibers in the oak wood is 179% at highest conversion. Similar results were also acquired from hardness tests. The decrease in the mechanical durability after aging for 28 d was very little.     

Study of macrophotoinitiator containing in-chain thioxanthone and coinitiator amines

Three kinds of macrophotoinitiator, PTXB, PTXE and PTXP, were synthesized by step-polymerization of thioxanthone and different amino monomers. The UV-vis spectra of PTXP, PTXE and PTXB are similar with slightly-shifted maximum absorption, and the fluorescence emission varies. The photopolymerization of three monomers with different functionality, methyl methacrylate (MMA), poly(propylene glycol) diacrylate (PPGDA) and trimethylolpropane triacrylate (TMPTA), initiated by these three types of macrophotoinitiators was studied through dilatometer and photo-DSC. The results show different photoinitiators behaviors towards monomers efficiently: PTXP is the most efficient for MMA, PTXE is the most efficient for PPGDA and PTXB is the most efficient for TMPTA. The efficiency of the photopolymerization is mainly effected by structure of amine in macrophotoinitiator.     

聚氨酯／聚烯烃互穿网络粘合剂的研究

制备了聚酯聚氨酯／聚丙烯酸酯及其它乙基单体聚合物热塑性互穿网络弹性体，将其溶解于溶剂中形成聚氨酯／聚烯烃粘合剂。考察了乙烯基单体的种类、用量、聚酯分子量、热活化时间等对粘合剂粘合性能的影响，同时测定了互穿网络弹性体的形态结构。     

Synthesis and characterizations of calcium di(meth)acrylate divinyl monomers and melt surface graft functionalization with linear low density poly(ethylene)

Calcium diacrylate (CDA) and calcium dimethacrylate (CDM) divinyl monomers were synthesized by a solvo thermal method. The FTIR spectra showed a peak at 1650 cm^?1 due to the presence of a C?C for both CDA and CDM. Proton NMR and carbon NMR confirmed the structure of CDA and CDM synthesized by a solvo thermal method. DSC determined the melting temperatures of CDA and CDM. XRD indicated the presence of a d₁₁₀ plane peak for CDA and CDM. The % weight residue that remained above 700°C in TGA method confirmed the higher thermal stability of CDA. Thus, synthesized CDA and CDM were surface grafted on linear low density poly(ethylene) (LLDPE) at 160°C under inert atmosphere by thermolysis method. FTIR confirmed the presence of C?O stretching due to CDA and CDM in LLDPE backbone after thermolysis reaction. ¹H‐NMR confirmed the chemical grafting of CDM onto LLDPE. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Reaction and miscibility of two diepoxides with poly(ethylene terephthalate)

Poly(ethylene terephthalate) (PET) was melt‐blended at 270°C with two epoxy monomers, diglycidyl ether of bisphenol A (DGEBA) and 3,4‐epoxycyclohexyl‐methyl‐3,4‐epoxycyclohexyl carboxylate (ECY). Intermediate proportions of the epoxy in the range of 20–0.5 wt % were used. If the epoxy monomers were added in a high proportion (10–20%), a large fraction did not react with PET. Calorimetric experiments showed that the unreacted fractions of both epoxies were miscible with the amorphous phase of the polyester. Only one glass‐transition temperature was detected. It was depressed as the epoxy content was increased. The transition was broad when the PET component was crystalline, and it was narrow when the PET component was made amorphous by quenching of the blend. These features were confirmed by dynamic thermal mechanical analysis. As is often the case for crystalline blends, the crystallization and melting temperatures decreased when the proportion of the epoxy was increased. Concerning the reactivity of the epoxy with PET, the behavior differed according to the nature of the epoxy. The DGEBA monomer showed a low reactivity. It was not effective for the chain extension of PET, and no increase in the intrinsic viscosity was observed under the experimental conditions. However, some functionalization of the chain ends may be possible at a high concentration of the epoxy. ECY was more reactive, and the molecular weight of the processed PET increased, although the value of the commercial untreated polyester was not attained. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1995–2003, 2003     

Preparation of pressure-sensitive adhesives from tung oil via Diels-Alder reaction

In this study, tung oil was polymerized with a dimaleimide (4,4’-methylene-bis(N-phenylmaleimide) (MPMI) and two diacrylates (poly(propylene glycol) diacrylate (PPGDA) and bisphenol A glycerolate diacrylate (BPAGDA) via Diels-Alder reaction (DA reaction) to prepare pressure-sensitive adhesives (PSAs). On the one hand, the polymer of tung oil and MPMI was readily prepared however it was too rigid to serve as a PSA. On the other hand, the polymerization of tung oil with PPGDA or BPAGDA resulted in PSAs with peel strengths ranging from 0.1 to 0.2 N cm⁻¹ and loop tacks ranging from 0.4 to 0.5 N. Nevertheless, tung oil reacted readily with acrylic acid to form adducts (TOAA) with lower content of conjugated diene groups than those of tung oil. The use of TOAAs instead of tung oil to polymerize PPGDA failed to increase the peel strength of the resulting PSAs. However, polymerizations of TOAAs with BPAGDA resulted in PSAs with much higher peel strengths and much higher loop tacks than the polymerization of tung oil with BPAGDA. In addition, the introduction of a small amount of MPMI in the polymerization of TOAA and PPGDA significantly shortened the curing time.     

Studies on castor oil–based polyurethane/polyacrylonitrile interpenetrating polymer network for toughening of unsaturated polyester resin

Tricomponent interpenetrating polymer network (IPN) systems involving castor oil, toluenediisocyanate (TDI), acrylonitrile (AN), ethylene glycol diacrylate (EGDA), and general‐purpose unsaturated polyester resin (GPR) were prepared with various compositions. The structures of the IPNs at various stages were confirmed using FTIR. The thermal stability of the IPNs was studied using TGA, which indicated that the polyurethane/polyacrylonitrile/GPR (PU/PAN/GPR) IPN underwent single‐stage decomposition, showing perfect compatibility at the IPN composition of 10 : 90 (PU/PAN : GPR). The mechanical properties such as tensile, flexural, impact, and hardness for the IPNs with various compositions were determined. It was found that the tensile strength of the GPR matrix was decreased and flexural and impact strengths were increased upon incorporating PU/PAN networks. The swelling properties in water and toluene were also studied. The morphology of the IPNs was studied using SEM. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 817–829, 2004     

Ionically conductive polymer gel electrolytes prepared from vinyl acetate and methyl methacrylate for electric double layer capacitor

In order to obtain highly conductive polymer electrolytes for an electric double layer capacitor, three kinds of polymer gel electrolytes were prepared. Vinyl acetate (VAc) and methyl methacrylate (MMA) were copolymerized with divinyl adipate (DA) and ethylene glycol dimethacrylate (EGDMA), respectively, in propylene carbonate (PC) containing tetraethylammonium tetrafluoroborate (TEATFB) to form network polymer gel electrolytes. MMA was also copolymerized with butylene glycol DMA for comparison. The polymer gel electrolytes obtained were characterized by means of thermogravimetry, complex impedance analysis, and cyclic voltammetry for use in the electric double layer capacitor. The ionic conductivities of the polymer gel electrolytes were dependent on the TEATFB concentration, temperature, and crosslinking degree. The polymer gel electrolytes in the VAc‐DA system exhibited higher room temperature conductivities (10⁻² S/cm) than those in the MMA‐EGDMA system. Further, the polymer gel electrolytes in the VAc‐DA system showed good electrochemical stability windows ranging from −4.0 to 4.0 V versus Ag. Thermal analysis revealed that the polymer gel electrolytes in both systems were stable up to 150°C. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 12–18, 2000     

Novel chemical-bonded polymerizable sulfur-containing photoinitiators comprising the structure of planar N-phenylmaleimide and benzophenone for photopolymerization

As a continuation of the research on chemical-bonded photoinitiators comprising the structure of planar N-phenylmaleimide (NPMI) and benzophenone (BP), three novel polymerizable sulfur-containing photoinitiator MTPBP, CMTPBP and BMTPBP were synthesized by introducing NPMI group into benzophenone (BP). BP was selected as the reference to evaluate their photoefficiency. These novel photoinitiators possess greatly red-shifted UV maximal absorption, and their fluorescence emission varies. Three representative types of different functionality monomers, methyl methacrylate (MMA), 1,6-hexanediol diacrylate (HDDA) and trimethylolpropane triacrylate (TMPTA), initiated by the three novel photoinitiators were studied through dilatometer and photo-DSC using unsaturated tertiary amine N,N-dimethylaminoethyl methacrylate (DMAEMA) as the coinitiator. The results show surprising high efficiency of these chemical-bonded photoinitiators towards different monomers in contrast to BP, and they can initiate photopolymerization without the coinitiator because of the photolysis at C-S bond. The results also verify that the higher viscosity of monomers and the larger molecular size of the photoinitiators may restrict the bimolecular H-abstraction reaction.     

SBR/P(St-MMA-AN)互穿网络聚合物的加工和力学性能

以丁苯胶乳为种子乳液，苯乙烯、甲基丙烯酸甲酯、丙烯腈的混合物为硬单体，二乙烯基苯为交联剂，在氧化还原引发体系下，以种子乳液聚合法得复合乳液，絮凝干燥后得到共聚物。研究了硬单体用量、硬单体配比、加工次数对聚合物力学性能的影响规律。结果表明，聚合物可反复进行热塑性加工，聚合物微观相畴随加工次数增多而变小。     

Effect of the polymer matrices on the immobilisation of microbial cells by radiation polymerisation

Streptomyces phaeochromogenes cells were immobilised by radiation polymerisation, at low temperature, using various acrylate and diacrylate monomers. The form and enzymatic activity of the immobilised cell composites were affected by the molecular structure of the monomers. The activities of the composites from acylate and diacrylate monomers increased with increased numbers of methylene or ethylene glycol units in the monomers. The water content of the immobilised cell composites was also affected by the molecular structure of the monomers. The pH and heat stabilities of the immobilised cell composites were increased when the polymer matrix had a porous sponge structure.     

Grafting mechanisms in hybrid miniemulsion polymerization

The ultimate objective of hybrid miniemulsion polymerization is to produce a water‐based crosslinkable coating through in situ grafting of a free radical growing acrylic polymer with an unsaturated resin. Certain authors have reported low grafting while others have reported higher. This article explores the factors that influence the grafting tendencies of these systems. Methacrylates such as methyl methacrylate (MMA) have a sterically hindered radical center that lowers its reactivity toward unsaturated resin. This steric hindrance from the methyl group forces grafting of this type of monomer to occur by abstraction of a hydrogen allylic to a resinous double bond. This chain transfer produces a relatively inactive radical on the resin that reduces the grafting efficiency. The transfer process also inherently produces some degree of terminated PMMA polymer within the particle. Grafting occurs in this type of system through termination of living PMMA chains with that radical produced on the resin. For relatively water‐soluble monomers such as MMA, grafting efficiency is further lessened by homogeneous nucleation resulting from the monomer hydrophilicity. These newly created particles cannot contain alkyd due to its hydrophobicity and thus inability to transport across the aqueous phase, and hence cannot produce grafted polymer. Nonetheless, degree of grafting of nearly 50% was observed in these systems. For hybrid systems involving an acrylate monomer such as butyl acrylate (BA), virtually complete grafting with alkyd was observed. This is due to the uninhibited BA radical center allowing the molecule to add directly through a resin double bond. This process offers the possibility for complete grafting. Homogeneous nucleation is not involved in this system due to the insolubility of BA in the aqueous phase. Resin double bond content and degree of conjugation also play an integral role in the grafting process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1825–1836, 2003