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1.
A series of exo-methylene 6-membered ring conjugated dienes, which are directly or indirectly obtained from terpenoids, such as β-phellandrene, carvone, piperitone, and verbenone, were radically polymerized. Although their radical homopolymerizations were very slow, radical copolymerizations proceeded well with various common vinyl monomers, such as methyl acrylate (MA), acrylonitrile (AN), methyl methacrylate (MMA), and styrene (St), resulting in copolymers with comparable incorporation ratios of bio-based cyclic conjugated monomer units ranging from 40 to 60 mol% at a 1:1 feed ratio. The monomer reactivity ratios when using AN as a comonomer were close to 0, whereas those with St were approximately 0.5 to 1, indicating that these diene monomers can be considered electron-rich monomers. Reversible addition fragmentation chain-transfer (RAFT) copolymerizations with MA, AN, MMA, and St were all successful when using S-cumyl-S’-butyl trithiocarbonate (CBTC) as the RAFT agent resulting in copolymers with controlled molecular weights. The copolymers obtained with AN, MMA, or St showed glass transition temperatures (Tg) similar to those of common vinyl polymers (Tg ~ 100 °C), indicating that biobased cyclic structures were successfully incorporated into commodity polymers without losing good thermal properties. 相似文献
2.
Preparation of composite polyacrylate latex particles with in situ‐formed methylsilsesquioxane cores
Composite polyacrylate latex particles were prepared through a simple method by dissolving organosilicon monomer methyltrimethoxysilane in a monomer mixture of acrylic monomers methyl methacrylate (MMA), n‐butyl acrylate (n‐BA), and acrylic acid (AA). With the addition of water needed for hydrolysis, methyltrimethoxylsilane hydrolyzed under catalysis by AA and further condensed to form polymeric methylsilsesquioxane (MSQ). The monomer mixture containing in situ‐formed MSQ was then subjected to emulsification and emulsion polymerization. Transmission electron microscopy (TEM) images showed that the obtained latex particles had a core–shell structure. Differences between the X‐ray photoelectron spectroscopy (XPS) results of the contents of silicon atoms on surfaces of films formed at temperatures above and below glass transition temperatures (Tgs) of polyacrylate evidenced that the cores were made up of MSQ and the shells were made up of polyacrylate. The static water contact angle measurements indicated that the incorporation of MSQ can result in composite latex with higher hydrophobicity. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
3.
Soap‐free poly(methyl methacrylate‐ethyl acrylate‐acrylic acid or methacrylic acid) [P(MMA‐EA‐AA or MAA)] particles with narrow size distribution were synthesized by seeded emulsion polymerization of methyl methacrylate (MMA), ethyl acrylate (EA) and acrylic acid (AA) or methacrylic acid (MAA), and the influences of the mass ratio of core/shell monomers used in the two stages of polymerization ([C/S]w) and initiator amount on polymerization, particle size and its distribution were investigated by using different monomer addition modes. Results showed that when the batch swelling method was used, the monomer conversion was more than 96.0% and particle size distribution was narrow, and the particle size increased first and then remained almost unchanged at around 600 nm with the [C/S]w decreased. When the drop‐wise addition method was used, the monomer conversion decreased slightly with [C/S]w decreased, and large particles more than 750 nm in diameter can be obtained; with the initiator amount increased, the particle size decreased and the monomer conversion had a trend to increase; the particle size distribution was broader and the number of new particles was more in the AA system than in the MAA system; but the AA system was more stable than the MAA system at both low and high initiator amount. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
4.
Ting-Chung Pan Jen-Feng Kuo Chuh-Yung Chen 《Journal of polymer science. Part A, Polymer chemistry》1991,29(5):709-718
The soapless emulsion polymerization of methyl methacrylate (MMA) and n-butyl acrylate (BA) containing various concentrations of sodium methacrylate (NaMA) or methacrylic acid (MMA) is studied. The hydrosoluble yields in final latexes are not larger than 1.3–5%, depending on the concentration of NaMA used. Below 25% conversion, the change of conversion with reaction time follows the square rule and the particle size is proportional to the 2/3 power of time. Above 25% conversion, serious gel effect occurs, and the conversion follows the seventh power on time and the growth of particle diameter obeys the 2.5 power on time. The multiple glass transition (Tg) occur below 20% conversion, where monomer droplets exist. NaMA added induces more Tgs. The effect of molecular weight of the copolymers obtained on Tg (even the molecular weight distributions were shown to be shouldertype bimodal) is estimated to be insignificant. Thus, the heterogeneity of copolymer compositions for multiple Tgs is ascribed to be caused from neither the molecular weight heterogeneity nor the shifts in compositions due to the difference of the monomer reactivity ratios. Referring to the results mentioned, we assume the sublayer surrounding the particle, rich with SO4? and COO? groups, and the concentration gradients of monomers in particles to illustrate particle morphology. In addition, the relatively hydrophilic sublayer is proposed to be closely relative with the occurrence of the composition heterogeneity in particles. 相似文献
5.
Jaroslav Mosná?ek Monica Bertoldo Chiara Cappelli Ivan Luká? 《Polymer Degradation and Stability》2007,92(5):849-858
Various diazo-compounds, 1,2,2,6,6-pentamethylpiperidin-4-yl diazoacetate (PMPDA), 2,2,6,6-tetramethylpiperidin-4-yl diazoacetate (TMPDA), methyl diazoacetate (MDA), 1,2,2,6,6-pentamethylpiperidin-4-yl 2-diazo-3-methyloxycarbonylpropionate (PMPMDS), 1,2,2,6,6-pentamethylpiperidin-4-yl 2-diazo-4-methyloxycarbonylbutanoate (PMPMDP), and one azide, methyl azidocarboxylate (MAC), were successfully prepared and grafted on polyethylene films by UV light (λ > 210 nm) activation. The treated films were characterised by FT-IR spectroscopy and contact angle measurements. Ab-initio quantum mechanical calculations allowed simulating the IR absorption spectra of the polymer grafted species. These last and the related grafting yields are discussed with reference to the diazo-compound structure and concentration. Up to 8.6 mol% of bonded groups (grafted groups/ethylene monomeric unit) were found without affecting the polymer molecular weight distribution, as shown by GPC analysis. All modified films bearing HAS groups showed very high photo-stability. 相似文献
6.
The seeded semicontinuous emulsion multi-copolymerization of butyl acrylate (BA),2-ethylhexyl acrylate (2EHA), methyl methacrylate (MMA), 2-hydroxyl propyl acrylate(HOPA) and acrylic acid (AA) was used to prepare the acrylic latexes with high-solidcontent. The effects of monomer emulsion feed rates (R_a) and (R/E)_E values, the ratio ofemulsifier amount between the initial charge (R) and the addition monomer emulsion (E),on the polymerization reaction features, the viscosities, surface tensions,particle sizes andparticle sizes distributions of latexes,T_g and the insoluble fractions of films, the 180° peelstrength, tack and holding power of pressure-sensitive adhesive (PSA) tapes, preparedfrom the latexes, were studied. Experimental study shows that the grafting and cross-linking fraction in the PSA tapes must be controlled within a suitable range to keep thebalance of the 180° peel strength, tack and holding power. 相似文献
7.
The distribution of 137Cs, 152Eu, 238U, and 85Sr in a solid/aqueous system (poly(methyl acrylate)/phosphate/composite in contact with groundwater, was investigated using
γ-Spectrometry and flourometry. The results were compared with earlier results with mineral phosphate in the solid phase.
The effect of contact time, pH and the concentration of concurrent element were studied. The ability of the prepared polymer
composites to keep the studied radioisotopes in the solid phase is much higher than mineral phosphate. The used polymer composites
have been prepared consisting of natural phosphate powder and the monomer methyl acrylate using gamma irradiation. The yield
of polymerization was followed up with respect to the irradiation dose using thermogravimetric analyzer (TGA). A thermomechanical
analyzer (TMA) was used to locate the area of the glass transition temperatures (T
g
) using the mode with alternative variable force; the mode with constant force was used to determine the T
g
of the pure polymer and the polymer composite prepared at the same irradiation dose. The T
g
of the pure poly(methyl acrylate) is 13 ± 3 °C, and the T
g
of poly(methyl acrylate)/phosphate/composites is 8 ± 3 °C. The T
g
were also determined using the DSC technique, and similar values were found. 相似文献
8.
Yuanyuan Gao Na Zhang Lianlian Zhu Zhaosheng Hou 《Russian Journal of Applied Chemistry》2017,90(10):1634-1639
Thermoplastic expandable microspheres (TEMs) having a core/shell structure were prepared via suspension polymerization with acrylonitrile (AN) and methyl methacrylate (MMA) as monomers and i-butane as blowing agent. The relationship between monomer compositions and expansion properties of the TEMs was explored. When the weight ratio of AN and MMA is 1: 1, suspension polymerization could yield TEMs having good expansion properties and heat stability at 120–130°C. The maximum expansion volume is 22.5 times of the original volume. The temperatures at the maximum expansion volume (Tm.e.), at the onsets of expansion (To.e.) and the onset of shrinkage (To.s.) are 80, 120–130, and 145°C, respectively. The micromorphologies were observed by polarizing optical microscope (POM), the results show that the TEMs have a core/shell structure. The blowing agent content in TEMs is–20 wt %, which was determined by thermogravimetric analysis (TGA). Dynamic light-scattering (DLS) measurements show that the TEMs have an average particle size of–20 μm and a wide particle size distribution. The presence of low-molecular alcohol in water phase could help to reduce the particle size distribution. 相似文献
9.
Huseyin Tas Lon J. Mathias 《Journal of polymer science. Part A, Polymer chemistry》2010,48(11):2302-2310
New ether dimer (ED‐Eh) and diester (EHDE) derivatives of α‐(hydroxymethyl)acrylate, each having two 2‐ethylhexyl side chains, and an amine‐linked di(2‐ethylhexyl)acrylate (AL‐Eh), having three 2‐ethylhexyl side chains, were synthesized and (co)polymerized to evaluate the effects of differences in the structures of the monomers on final (co)polymer properties, particularly glass transition temperature, Tg. The free radical polymerizations of these monomers yielded high‐molecular–weight polymers. Cyclopolymer formation of ED‐Eh and AL‐Eh was confirmed by 13C NMR analysis and the cyclization efficiencies were found to be very high (~100%). Copolymers of ED‐Eh, EHDE, and AL‐Eh with methyl methacrylate (MMA) showed significant Tg decreases over poly(methyl methacrylate) (PMMA) due to 2‐ethylhexyl side groups causing “internal” plasticization. Comparison of the Tg's of the copolymers of 2‐ethylhexyl methacrylate, ED‐Eh, EHDE, and AL‐Eh with MMA revealed that the impacts of these monomers on depression of Tg's are identical with respect to the total concentration of the pendent groups. This is consistent with an earlier study involving copolymers of monomers comprising one and two octadecyl side groups with MMA. That is, the magnitude of decrease in Tg's was quantitatively related to the number of the 2‐ethylhexyl pendent groups in the copolymers rather than their placement on the same or randomly incorporated repeat units. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2302–2310, 2010 相似文献
10.
Novel solid-phase microextraction (SPME) fibres containing methyl, ethyl, butyl acrylate and methacrylate were first prepared by a sol–gel technique and investigated for determination of selected organoarsenic compounds (lewisite, methyldichloroarsine, phenyldichloroarsine, diphenylchloroarsine and triphenylarsine) from water samples. The influence of sorption and desorption temperature and time for extraction efficiency were examined. The best new fibre coatings (methyl acrylate (MA), methyl methacrylate (MMA) and combination of methyl acrylate and methacrylate (MA/MMA)) for analysis of organoarsenic compounds were selected and compared with commercial fibres. The distribution coefficients Kfs were determined for the best novel fibres and for absorption commercial fibres. The highest Kfs value were obtained for MA/MMA and MMA fibres and were respectively 9458 and 6561 for lewisite and 6458 and 5884 for triphenylarsine. The limit of detection and quantification were determined for the three laboratory obtained fibres (MA, MMA and MA/MMA). LODs for tested fibres, at a signal-to-noise of 3, were 0.03–0.3 ng mL−1. LOQs for selected coatings, at signal-to-noise of 10, were 0.1–0.8 ng mL−1. The relative standard deviations (RSD) for all measurements were 4.3–6.5% (n = 9) and relative errors were 2.5–5%. The laboratory obtained fibres were used for environmental analysis of pore water samples from the Baltic Sea. 相似文献
11.
Poly(methyl acrylate) (PMA), poly(vinyl acetate) (PVAc) and poly(n-isopropylacrylamide) (PNIPAAm) with their respective Tg of 6, 32, and 145 °C were employed to gel the LiI/I2/tertiary butylpyridine electrolyte system for preparation of the gelled-type dye-sensitized solar cells (DSSC). The light-to-electricity conversion efficiencies of DSSCs gelled by PMA, PVAc, and PNIPAAm were 7.17%, 5.62%, and 3.17%, respectively under simulated AM 1.5 sunlight irradiation, implying that utilizing the polymer of lower Tg to gel the electrolytes leaded to better performance of the DSSCs. Their short-circuit current density and IPCE also showed the similar trend. Electrochemical impedance spectroscopy of the gelled DSSCs revealed that utilizing the polymer of lower Tg resulted in lower impedance associated with the Nernstian diffusion within the electrolytes. The results were consistent with the observation that the molar conductivity of gelled electrolytes was higher as the polymer of lower Tg was applied, which can be justified by Vogel-Tammann-Fulcher (VTF) equation. 相似文献
12.
Graft copolymerization of 2-hydroxyethyl methacrylate(HEMA) and mixtures of HEMA with methyl methacrylate (MMA) onto hide powder was attempted using ceric ammonium nitrate as initiator, with a view to optimize the conditions for graft copolymerization. Percent grafting and grafting efficiency were calculated for various variables such as monomer concentration, initator concentration and mole ratio of HEMA to MMA. Rp, Rg and Rh (rates of polymerization, grafting and homopolymerization respectively) were also evaluated. It was observed that Rp increased linearly with increasing concentration of MMA except at very low concentrations of the monomer. An explanation is given for the effect of variables on extent of grafting and grafting efficiency. 相似文献
13.
The new functional styrenic monomer, 4-trisylmethyl styrene (TsiMS) [Tsi=trisyl=tris(trimethylsilyl)methyl], was synthesized by reacting 4-chloromethyl styrene (CMS) with trisyllithium (TsiLi) in tetrahydrofuran (THF) solvent in the presence of copper chloride (CuCl). Attempt for the free radical polymerization of TsiMS by α,α′-azobis(isobutyronitrile) (AIBN) as an initiator at 70 ± 1 °C failed for several periods of times. This result showed that the trisyl group is a highly sterically hindered substituent and, subsequently, TsiMS becomes resistant for polymerization. Therefore, for preparation of new methacrylic, acrylic and dienic copolymers of TsiMS, we firstly synthesized the copolymers of CMS with different monomers such as methyl methacrylate (MMA), ethyl methacrylate (EMA), methyl acrylate (MA), ethyl acrylate (EA), n-butyl acrylate (BA) and isoprene (IP) by free radical polymerization method in toluene solution at 70 ± 1 °C using AIBN initiator to give the copolymers I-VI in good yields. The copolymer compositions were obtained using related 1H NMR spectra and the polydispersity indices of the copolymers determined using gel permeation chromatography (GPC). The trisyl groups were then covalently attached to the obtained copolymers as side chains by reaction between excess of TsiLi and benzyl chloride bonds of CMS units, to give the copolymers - in 80-92% yields. All the resulted polymers were characterized by FT-IR, 1H NMR and 13C NMR spectroscopic techniques. The solubility of all the copolymers was examined in various polar and non-polar solvents. The glass transition temperature (Tg) of all copolymers was determined by differential scanning calorimetry (DSC) apparatus. The Tg value of copolymers containing bulky trisyl groups was found to increase with incorporation of trisyl groups in polymer structures. The presence of trisyl groups in polymer side chains, create new macromolecules with novel modified properties. 相似文献
14.
Dingying Zhou Hongxiang Teng Koutarou Koike Yasuhiro Koike Yoshiyuki Okamoto 《Journal of polymer science. Part A, Polymer chemistry》2008,46(14):4748-4755
Fluoroalkyl methacrylates, 2,2,2‐trifluoroethyl methacrylate ( 1 ), hexafluoroisopropyl methacrylate ( 2 ), 1,1,1,3,3,3‐hexafluoro‐2‐methyl‐2‐propyl methacrylate ( 3 ), and perfluoro t‐butyl methacrylate ( 4 ) were synthesized. Homopolymers and copolymers of these fluoroalkyl methacrylates with methyl methacrylate (MMA) were prepared and characterized. With the exception of the copolymers of MMA and 2,2,2‐trifluoroethyl methacrylate ( 1 ), the glass transition temperatures (Tgs) of the copolymers were found to deviate positively from the Gordon‐Taylor equation. The positive deviation from the Gordon‐Taylor equation could be accounted for by the dipole–dipole intrachain interaction between the methyl ester group and the fluoroalkyl ester group of the monomer units. These Tg values of the copolymers were found to fit with the Schneider equation. The fitting parameters in the Schneider equation were calculated, and R2 values, the coefficients of determination, were almost 1.0. The refractive indices of the copolymers, measured at 532, 633, and 839 nm wavelengths, were lower than that of PMMA and showed a linear relationship with monomer composition in the copolymers. 2 and MMA have a tendency to polymerize in an alternating uniform monomer composition, resulting in less light scattering. This result suggests that the copolymer prepared with an equal molar ratio of 2 and MMA may have useful properties with applications in optical devices. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4748–4755, 2008 相似文献
15.
Wayne W. Y. Lau C. S. Lee S. Y. Lee S. H. Goh 《Journal of polymer science. Part A, Polymer chemistry》1993,31(6):1499-1503
Copolymers of 1,2,2,6,6-pentamethyl-4-piperidinyl m-isopropenyl-α,α-dimethylbenzyl carbamate (CB) with styrene (S) and with methyl methacrylate (MMA) were synthesized using AIBN as initiator. S–CB copolymers made from feed ranging from 0.45–0.94 mole fractions S and MMA-CB copolymers made from feed of 0.34–0.88 mole fractions MMA were used to determine the monomer reactivity ratios r1 and r2. The structure of S–CB copolymers was inferred to be mainly of a random nature and in the MMA–CB copolymerization system there is a stronger tendency to form alternating copolymers. © 1993 John Wiley & Sons, Inc. 相似文献
16.
Katsuhiko Sato 《Journal of colloid and interface science》2012,387(1):123-126
Poly(methyl methacrylate) (PMMA) microcapsules were prepared by the in situ polymerization of methyl methacrylate (MMA) and N,N′-methylenebisacrylamide on the surface of calcium carbonate (CaCO3) particles, followed by the dissolution of the CaCO3 core in ethylenediaminetetraacetic acid solution. The microcapsules were characterized using fluorescence microscopy, atomic force microscopy, scanning electron microscopy, and Fourier transform infrared spectroscopy. The average sizes of the CaCO3 particles and PMMA capsules were 3.8 ± 0.6 and 4.0 ± 0.6 μm, respectively. A copolymer consisting of MMA and rhodamine B-bearing MMA was also used to prepare microcapsules for fluorescent microscopy observations. Fluorescein isothiocyanate-labeled bovine serum albumin was enclosed in the PMMA microcapsules and its release properties were studied. 相似文献
17.
Marissa Volz Ulrich Ziener Ulrich Salz Jörg Zimmermann Katharina Landfester 《Colloid and polymer science》2007,285(6):687-692
The solid photoinitiator Lucirin TPO was encapsulated within a polymer shell by using the miniemulsion process. A solution
of Lucirin TPO in methyl methacrylate (MMA) or butyl acrylate (BA)/MMA mixture was miniemulsified in water followed by a polymerization
process in which phase separation of the Lucirin TPO and the formed polymer led to amorphously solidified Lucirin TPO nanoparticles
encapsulated by polymer. These nanocapsules were freeze-dried and could be redispersed in acidic monomers, which are applied
in polymeric dental adhesives. It is shown by 1H nuclear magnetic resonance spectroscopy that the shell separates the Lucirin TPO, which is sensitive to degradation in acidic
media, from an ambient acidic monomer phase and protects it from fast decomposition. Investigations of the release kinetics
of Lucirin TPO from the nanocapsules reveal that the kinetics are strongly dependent on the composition of the surrounding
continuous phase. 相似文献
18.
High hydrogen-containing polymethylsiloxane(H-PDMS)/polyacrylate composite emulsion was synthesized by a drop-adding method for monomer emulsion. The effects of weight fraction of H-PDMS on the stability of composite emulsion, water resistance and heat-aging resistance of the latex membrane have been investigated. The TEM demonstrated that latex particles are a core-shell structure. By analyzing the spectrums of FTIR and 1H-NMR, it can be indicated that H-PDMS had reacted with acrylate monomer resulting chemical bond formation. The core-shell structure and chemical bond play an important role to restrain phase separation of composite emulsion and enhance the stability of the emulsion. By analyzing the surface tension, apparent viscosity and morphological structure, the results showed that the stable composite emulsion system can be obtained in which the average latex particle size was smaller than 90 nm when weight fraction of H-PDMS is below 16% (based on the weight of acrylate monomer), the stable emulsion system can be obtained in which the average latex particle size becomes larger than 90 nm when the weight fraction of H-PDMS is above 20% of the acrylate monomer. The DSC demonstrated that the Tg of pure polyacrylate is 49°C, and there is only one Tg (35°C) when the weight fraction of H-PDMS is 13%, but there are two Tg (15°C and 25°C) when the weight fraction of H-PDMS is 16%. In addition, the water resistance and heat-aging resistance of composite latex membrane enhanced gradually with the increase of amount of H-PDMS. 相似文献
19.
《Radiation Physics and Chemistry》2009,78(2):112-118
Graft copolymers of polyurethane (PU) with various vinyl monomers were synthesized through a one-pot but two-step miniemulsion polymerization process. Firstly, the polycondensation of isophorone diisocyanate (IPDI) with hydroxyl-terminated polybutadiene (HTPB) had been performed in aqueous miniemulsion at 40 °C in order to obtain PU dispersions. Consecutively, an in-situ graft copolymerization of the vinyl monomers with the synthesized PU was initiated by γ-ray radiation at room temperature. The grafting efficiency of PU with vinyl monomer (GPU/monomer) was calculated from 1H NMR spectra and the particle morphology of the final hybrid latex was observed by transmission electron microscopy (TEM). As there was no monomer transferring in miniemulsion system, homogenous hybrid particles would be synthesized provided that the monomer was miscible with PU, such as styrene. With the increase of the polarity of the monomer, the compatibility of PU with monomer decreased. GPU/monomer varied as GPU/styrene(37%)>GPU/butyl acrylate (BA)(21%)>GPU/methyl methacrylate (MMA)(12%). The proportion of homogeneous nucleation would increase as the hydrophilicity of the monomer increased. High temperature would destabilize the miniemulsion so as to result in a less grafting efficiency. Compared to the phase separation during the seeded emulsion polymerization, the miniemulsion polymerization method facilitated the preparation of homogeneous materials owing to its monomer droplet nucleation mechanism. 相似文献
20.
In order to obtain functional polymer latex particles with clean surface and with surface carboxyl groups, P(MMA-EA) seed particles with the diameter of 335 nm were first synthesized via soap-free batch emulsion polymerization of methyl methacrylate (MMA) and ethyl acrylate (EA), and then the seeded emulsion copolymerization of MMA, EA and MAA (methacrylic acid) onto the seed particles were performed in the absence of emulsifier. Influences of ingredients and conditions on polymerization, latex particle size (Dp) and its distribution were investigated. Results showed that most of the monomers polymerized onto the seed latex particles in the second step of polymerization by using drop-wise addition method, and Dp increased from 483 nm to 829 nm with the mass ratio of core/shell monomers [C]/[S] decreased from 1:2 to 1:15. It was found that Dp decreased with the increase of MAA and initiator amounts, and the size of the latex particles became uniform with the decrease of MAA amount and with the increase of [C]/[S] value. 相似文献