Synthesis and thermal properties of poly(n‐butyl acrylate)/n‐hexadecane microcapsules using different cross‐linkers and their application to textile fabrics

This study focused on the preparation, characterization, and determination of thermal properties of microencapsulated n‐hexadecane with poly(butyl acrylate) (PBA) to be used in textiles with heat storage property. Microcapsules were synthesized by emulsion polymerization method, and the particle size, particle size distribution, shape, and thermal storage/release properties of the synthesized microcapsules were analyzed using Fourier‐transform infrared spectroscopy, scanning electron microscopy, and differential scanning calorimetry techniques. Allyl methacrylate, ethylene glycol dimethacrylate, and glycidyl methacrylate were used as cross‐linkers to produce unimodal particle size distribution. MicroPBA microcapsules produced using allyl methacrylate cross‐linker were applied to 100% cotton and 50/50% cotton/polyester blend fabrics by pad‐cure method. The mean particle size of microcapsules ranges from 0.47 to 4.25 μm. Differential scanning calorimetry analysis indicated that hexadecane in the microcapsules melts at nearly 17°C and crystallizes at around 15°C. The contents of n‐hexadecane of different PBA microcapsules were in the range of 27.7–50.7%, and the melting enthalpies for these ratios were between 65.67 and 120.16 J/g, respectively. The particle size and thermal properties of microcapsules changed depending on the cross‐linker type. The cotton and 50/50% cotton/polyester blend fabrics stored 6.56 and 28.59 J/g thermal energy, respectively. The results indicated that PBA microcapsules have the potential to be used as a solid‐state thermal energy storage material in fabrics. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation of poly(tert‐butyl acrylate)‐poly(acrylic acid) amphiphilic copolymers via radiation‐induced reversible addition–fragmentation chain transfer mediated polymerization of tert‐butyl acrylate

Poly(tert‐butyl acrylate) (PtBA) is a versatile hydrophobic macromolecule usually preferred in the development of new materials for a host of applications. PtBA homopolymers with well‐defined structure and controlled molecular weight in a wide range were successfully synthesized via radiation‐induced reversible addition–fragmentation chain transfer (RAFT) polymerization in the presence of a trithiocarbonate type RAFT agent. The polymerization of tBA was performed under ⁶⁰Co γ‐irradiation in the presence of 2‐(dodecylthiocarbonothioylthio)‐2‐methylpropionic acid (DDMAT) as the RAFT agent in toluene at room temperature with three [tBA]/[DDMAT] ratios (400, 600 and 1000) and different irradiation times. Radiation‐induced polymerization of tBA displayed controlled free radical polymerization characteristics: a narrow molecular weight distribution (M_w/M_n ~ 1.1), pseudo first order kinetics and controlled molecular weights. The system followed the RAFT polymerization mechanism even at very low amounts of RAFT agent ([tBA]/[DDMAT] = 1000), and molecular weights up to 113 900 with narrow dispersity (Ð =1.06) were obtained. PtBA was further hydrolysed into different amphiphilic PtBA‐co‐poly(acrylic acid) (PAA) copolymers by low (27.5%) and high (77.3%) degrees of hydrolysis. The pH sensitivity of the two copolymers was investigated by dynamic light scattering at pH 2 and pH 9 (above and below the pK_a value of PAA) and their hydrodynamic diameters and zeta potential values were determined. © 2020 Society of Chemical Industry     

Ultrasonically initiated emulsion polymerization of n‐butyl acrylate

Ultrasonically initiated emulsion polymerization of n‐butyl acrylate (BA) without added initiator has been studied. The experimental results show that high conversion of BA can be reached in a short time by employing an ultrasonic irradiation technique with a high purge rate of N₂. The viscosity average molecular weight of poly(n‐butyl acrylate) (PBA) obtained reaches 5.24 × 10⁶ g mol^?1. The ultrasonically initiated emulsion polymerization is dynamic and complicated, with polymerization of monomer and degradation of polymer occurring simultaneously. An increase in ultrasound intensity leads to an increase in polymerization rate in the range of cavitation threshold and cavitation peak values. Lower monomer concentration favours enhancement of the polymerization rate. ¹H NMR, ¹³C NMR and FTIR spectroscopies reveal that there are some branches and slight crosslinking, and also carboxyl groups in PBA. Ultrasonically initiated emulsion polymerization offers a new route for the preparation of nanosized latex particles; the particle size of PBA prepared is around 50–200 nm as measured by transmission electron microscopy. © 2001 Society of Chemical Industry     

Molecular weight development in emulsion copolymerization of n‐butyl acrylate and styrene

The seeded emulsion copolymerization of n‐butyl acrylate and styrene in a weight ratio of 50/50 was investigated. The effect of the type of process (batch vs. semicontinuous) and the amounts of initiator and emulsifier charged into the reactor on the time evolution of the fractional conversion, number of polymer particles, and weight‐average molecular weight (M_w) was analyzed. It was found that the M_w depends to a slight extent on the type of process and the emulsifier concentration and to a larger extent on the initiator concentration. The molecular weight distributions (MWDs) and the gel content of the final latexes were also analyzed. In the absence of chain transfer agents (CTAs), the fraction of gel was higher in the semicontinuous processes. It was also found that the gel content increased with increasing initiator concentration in the recipe. The addition of 1 wt % CTA avoided gel formation and led to an important reduction of the M_w. Nevertheless, the MWDs presented a shoulder or even a second peak at high molecular weights that was due to reactions of chain transfer to the polymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1918–1926, 2003     

Damping of vinyl acetate–n‐butyl acrylate copolymers

A photopolymerization process at room temperature was devised to copolymerize vinyl acetate (VAc) and n‐butyl acrylate (BA) mainly to prepare rubber‐like damping sheet bearing pressure‐sensitive adhesive property in this study. The investigations using both the differential scanning calorimeter and rheometric dynamic analysis show the existence of two glass transition temperatures for each copolymer. The scanning electron microscopic pictures reveal that the degree of microphase separation increases with increasing annealing time at 70°C. It was suggested that the rubbery domain (formed by the PBA blocks) disperses in the glassy domain (constituted by the PVAc blocks), making an effective damping entity. Excellent damping was observed for the copolymer samples, with the tanδ peak values as high as 1.76–1.80 at a certain temperature range and with tanδ> 0.3 at quite wide temperature ranges. In addition, the copolymers containing more VAc tend to have the higher damping. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1396–1403, 2004     

Effect of crosslinker,buffer, and blending on damping properties of poly(styrene‐acrylonitrile)/poly(ethyl acrylate‐ n‐butyl acrylate) latex interpenetrating polymer networks

A series of poly(styrene‐acrylonitrile)/poly(ethyl acrylate‐n‐butyl acrylate) latex interpenetrating polymer networks (LIPNs) are synthesized by changing the kind of crosslinker and introducing a buffer. The results show that the crosslinker has an important effect on the damping properties of the LIPNs; divinylbenzene is the best crosslinker in the study. Moreover, introducing a buffer into LIPNs leads to an increase of the damping values over the temperature range where the damping value surpasses 0.5. The LIPN blend prepared by mixing LIPNs results in broadening of the damping peak, therefore improving the damping properties. Tests of the damping properties show that the LIPNs have good practical value. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2347–2351, 2002     

Experimental study of the spontaneous thermal homopolymerization of methyl and n‐butyl acrylate

This article presents an experimental study of the spontaneous thermal homopolymerization of methyl acrylate (MA) and n‐butyl acrylate (nBA) in the absence of any known added initiators at 120 and 140°C in a batch reactor. The effects of the solvent type, oxygen level, and reaction temperature on the monomer conversion and polymer average molecular weights were investigated. Three solvents, dimethyl sulfoxide (DMSO; polar, aprotic), cyclohexanone (polar, aprotic), and xylene (nonpolar) were used. The spontaneous thermal polymerization of MA and nBA in DMSO resulted in a lower conversion and higher average molecular weights in comparison to polymerization in cyclohexanone and xylene under the same conditions. The highest final conversion of both monomers was obtained in cyclohexanone. The high polymerization rate in cyclohexanone was most likely due to an additional initiation mechanism where cyclohexanone complexed with the monomer to generate free radicals. Bubbling air through the mixture led to a higher monomer conversion during the early stage of the polymerization and a lower polymer average molecular weight in xylene and cyclohexanone; this indicated the existence of a distinct behavior between the air‐ and nitrogen‐purged systems. Matrix‐assisted laser desorption/ionization time‐of‐flight analysis of the polymer samples taken from nitrogen‐bubbled batches did not reveal fragments from initiating impurities. On the basis of the identified families of peaks, monomer self‐initiation is suggested as the principal mode of initiation in the spontaneous thermal polymerization of MA and nBA at temperatures above 100°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Poly(butyl acrylate) polymer enhanced phase segregation and morphology of organic semiconductor for solution-processed thin film transistors

The phase segregation as a result of mixing organic semiconductors with polymeric additives has been reported as an intriguing avenue to optimize semiconductor crystal microstructure, active layer composition and charge carrier transport. In this work, we report the mixing of organic semiconductor 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) with poly(butylacrylate) as a polymer additive to control the semiconductor crystal growth and morphology. The incorporation of poly(butylacrylate) induces a vertical phase segregation but a more predominant lateral phase segregation with TIPS pentacene. Along with a solvent vapor annealing technique, poly(butylacrylate) evenly distributes the semiconductor nuclei on the polymer matrix, and results in organic crystal with enlarged grain width. In addition, the randomized crystal growth of TIPS pentacene has been significantly reduced, giving rise to a 25-fold decrease in misorientation angle. The bottom-gate, top-contact thin film transistors with the poly(butylacrylate)/TIPS pentacene mixture as the active layer demonstrated an improved hole mobility of 0.11 cm²/Vs. We believe the phase segregation induced by the poly(butylacrylate) polymer as well as the solvent vapor annealing method as reported in this work can be facilely replicated on other organic semiconductors to realize high performance organic electronic device applications.     

Influence of shear stress treatment on stress‐strain properties of methyl methacrylate‐crosslinked butyl acrylate core‐shell polymers

The incorporation of multilayer toughness modifiers to glassy polymers proceeds frequently by kneading the polymers in a molten state. This process influences the primary structure of the modifier and the properties of the blend in dependence on a shear stress intensity. In this article, we compare the properties of polymer materials prepared from a multilayer poly(methyl methacrylate) core, butyl acrylate copolymer interlayer, and methyl methacrylate copolymer shell particles {P[MMA‐(BAC‐co)‐(MMA‐co)]} by press‐molding from powder and from polymer obtained by stirring a melt of this powder in the chamber of a Brabender mixer (200°C, 60 rpm, 10 min). The powder is obtained from a latex by coagulation after polymer synthesis in emulsion. Tensile testing shows different responses of the particle polymers when crosslinked in the middle layer by diallylphthalate (DAP) or by triallylcyanurate (TAC). Although many of the properties of the samples with DAP are improved by kneading, the presence of TAC in polymer particles led mostly to less desirable properties. The maximum percent strain in the polymer with 4.2 wt % of DAP upon shearing increases from 27% to 50%. In the samples with 4.5% TAC the maximum percent strain falls from 39% to 7%. Comparison of Young's modulus E for identical samples shows an analogous effect: a shift from 429 MPa to 638 MPa and from 624 MPa to 548 MPa. The design of the polymer particles used in this work leads to the conclusion that stress during kneading induces a partial desintegration of the crosslinked cage around the particle core. Thus, the varied behaviors of polymers used in this study are connected with the BAC‐co network structure and its transformations during the shear stress treatment of the initial polymer material. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 493–501, 1999     

Novel microporous poly(vinylidene fluoride)‐graft‐poly(tert‐butyl acrylate) electrolytes for secondary lithium batteries

BACKGROUND: Much interest has recently been shown in improving the performance of lithium‐ion polymer batteries with gel polymer electrolytes (GPEs) due to a rapid expansion in industrial demand. Novel GPEs based on poly(vinylidene fluoride)‐graft‐poly(tert‐butyl acrylate) (PVDF‐g‐tBA) microporous mats are suggested in this study. RESULTS: Microfibrous polymer electrolytes were prepared using electrospinning and characterized for extent of grafting, morphology, crystallinity, electrochemical stability, ionic conductivity, interfacial resistance and cell cycleability. The degree of crystallinity was lower for tBA‐grafted PVDF mats than that of neat PVDF. The PVDF‐g‐tBA showed an improvement in the ionic conductivity, electrochemical stability, interfacial resistance and cyclic performance. CONCLUSION: The tBA‐grafted PVDF microporous electrolytes are promising candidates for enhancing the performance of lithium‐ion polymer batteries. Copyright © 2008 Society of Chemical Industry     

Compatibility studies with blends based on poly(n‐butyl methacrylate) and polyacrylonitrile

In this study, poly(n‐butyl methacrylate) (PBMA) was prepared by a suspension polymerization process, and blending with polyacrylonitrile (PAN) in N,N‐dimethyl acetamide to prepare PAN/PBMA blends in various proportions. Hansen's three dimensional solubility parameters of PAN and PBMA were calculated approximately through the contributions of the structural groups. The compatibility in these blend systems was studied with theoretical calculations as well as experimental measurements. Viscometric methods, Fourier transform infrared spectroscopy, dynamic mechanical analysis, scanning electron microscopy, and thermogravimetric analysis were used for this investigation. All the results showed that a partial compatibility existed in PAN/PBMA blend system, which may be due to the intermolecular interactions between the two polymers. And, the adsorption experiment results showed that the addition of PBMA contributed to the enhancing adsorptive properties of blend fibers, which lays the foundation for further studying PAN/PBMA blend fibers with adsorptive function. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Influence of temperature and penetration depth on photopolymerization of n‐butyl acrylate using a narrow channel reactor

The influence of temperature and reactor size on photopolymerization kinetics of n‐butyl acrylate (n‐BA) using narrow channel reactors has been investigated. Experimental results have shown that increase in temperature and decrease in size of the reactor increases the monomer conversion. The effect of temperature was studied by immersing the reactor in a water bath maintained at different temperatures. A narrow channel glass reactor, 900 mm long, with diameters 1.5 mm, 1.0 mm, and 0.5 mm respectively were used to study the effect of light penetration depth on the rate of polymerization and molecular weights of the polymer produced. The degree of branching in the polymer produced was also estimated and compared with published data. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Two‐dimensional NMR studies of styrene/n‐butyl acrylate copolymers synthesized by atom transfer radical polymerization

Copolymers of styrene and n‐butyl acrylate were prepared by atom transfer radical polymerization (ATRP) using CuBr/N,N,N′,N′,N″‐pentamethyl‐diethylenetriamine as catalyst and Methyl 2‐bromopropionate as initiator. The polydispersity of the copolymers is quite low (1.1–1.3). ¹³C {¹H} NMR spectra of these copolymers show that the methylene and methine signals of the main chain are compositional sensitive and highly overlapped. Even the distortionless enhancement by polarization transfer (DEPT) was not able to assign the complex and overlapping signals. Assignments of the various resonance signals were done with the help of heteronuclear single quantum coherence (HSQC), total correlation spectroscopy (TOCSY), and heteronuclear multiple bond correlation (HMBC) experiments. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Initiator‐free photopolymerization of common acrylate monomers with 254 nm light

Using an available light source at a wavelength of 254 nm, common acrylate monomers were polymerized without any photoinitiators, which was confirmed using Fourier transform IR (FTIR) spectroscopy, ¹H NMR, gel permeation chromatography and fast atom bombardment mass spectrometric measurements. It was found that phenyl acrylate shows higher conversion than n‐ and t‐butyl acrylates. A trifunctional acrylate was also used for UV curing. The cured films were fabricated successfully on different kinds of substrates by using a batch‐ or conveyor‐type irradiation apparatus. It is indicated from FTIR spectral measurements that ca 40%–50% of acryloyl groups are consumed by the photopolymerization. Oxygen concentration in the sample chamber influences the photopolymerization, indicating that the polymerization proceeds via a radical process. © 2018 Society of Chemical Industry     

丙烯酸丁酯与N-羟甲基丙烯酰胺共聚物增韧PLA

将丙烯酸丁酯(BA)与N-羟甲基丙烯酰胺(NA)共聚合制备柔性共聚物P(BA-NA),再用P(BA-NA)增韧聚乳酸(PLA),研究了增韧体系的力学性能、微观形态与共聚单体配比、共聚物含量之间的关系。当n(BA)/n(NA)为30∶1,w[P(BA-NA)]为8%时,PLA/P(BA-NA)复合材料的拉伸断裂应变提高了约97倍,悬臂梁缺口冲击强度提高了1.5倍,拉伸强度为39 MPa。采用扫描电子显微镜观察发现,P(BA-NA)能够均匀分散在PLA基体中,两者相容良好。     

Prediction and experiment of core–shell particle morphology of vinyl acetate and butyl acrylate

In this article, the particle morphology in emulsion polymerization of the poly(vinyl acetate) (PVAc)/poly(butyl acrylate) (PBA) system is investigated. With the use of the basic data in literature, the relevant interface tensions and viscosity are estimated with the equation proposed in literature. The time achieved to equilibrium morphology is predicted with cluster dynamics proposed by Gonzalez. The experiment result is consistent with that of prediction. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2930–2937, 2002; DOI 10.1002/app.10297     

Grafting of styrene onto poly(butyl acrylate) in emulsion

The effect of time, temperature, the concentration of initiator and emulsifier, and the ratio of starting polymer to monomer on the degree of conversion (MC) of styrene and the grafting efficiency (GE) of polystyrene has been investigated. The reaction was initiated with potassium persulphate. It has been found that the degree of conversion of styrene and the grafting efficiency change in opposite directions when plotted as functions of the reaction parameters studied. The graft copolymerization is assisted by short reaction times and weight ratios of poly(butyl acrylate) to styrene greater than unity. The results obtained suggest that higher grafting efficiencies are obtained when the concentration of emulsifier is below its c.m.c. (critical micellar concentration) value. When using two different anionic emulsifiers it has been observed that the effect of initiator concentration on the degree of conversion of styrene and the grafting efficiency is complicated. Both the quantities studied (MC and GE) exhibit extrema in the range of initiator concentration studied (3.7?33.3 × 10^?5 mol dm^?3 of H₂O). No meaningful effect of temperature in the range 60°–90°C or that of dodecyl mercaptan (molecular weight regulator) used in an amount 0–0.4% in relation to poly(butyl acrylate) and styrene has been observed on the MC and GE values.     

Poly(ethylene glycol)-block-poly(butyl acrylate). I. Synthesis

Prepolymers of poly(ethylene oxide) (Pre-PEO) were synthesized by reacting azoisobutyronitrile (AIBN) with poly(ethylene glycol) (PEG), and their structures were characterized by IR and UV. The molecular weight of pre-PEO was related to the feed ratio and reaction time. These prepolymers can be used to prepare block copolymers—poly(ethylene oxide)-block-poly(butyl acrylate) (PEO-b-PBA) by radical polymerization in the presence of butyl acrylate (BA). Solution polymerization was a suitable technique for this step. The yield and the molecular weight of the product were related to the ratio of the prepolymer to BA, the reaction time, and temperature. GPC showed that the molecular weight increased with a higher ratio of BA to pre-PEO. The intrinsic viscosity of the copolymers was only slightly dependent on reaction time, but decreased at higher reaction temperatures, as did the amount of PBA homopolymer. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1667–1674, 1997     

反相浓乳液方法制备多孔聚丙烯酸丁酯弹性体材料

以丙烯酸丁酯为单体,二乙烯基苯为交联剂,偶氮二异丁腈为引发剂,山梨糖醇酐单油酸酯为乳化剂,水为分散相,用反相浓乳液法制备了泡孔型结构的聚丙烯酸丁酯(PBA)弹性体材料,考察了聚合反应温度、乳化剂用量、分散相体积分数对PBA弹性体材料泡孔结构的影响,并通过扫描电镜对泡孔结构进行了表征。结果表明,聚合反应温度宜控制为50~60℃;随着乳化剂质量分数从10%增加到30%,PBA弹性体的孔径逐渐减小,并且泡孔间的通道数量增多;随着分散相体积分数的增加,PBA弹性体材料的泡孔直径和通道直径逐渐增大,孔隙率增加,密度降低。