Quinone copolymerization. I. Reactions of p-chloranil,p-benzoquinone,and 2,5-dimethyl-p-benzoquinone with vinyl monomers under free-radical initiation

The free-radical copolymerization reactions of p-chloranil, p-benzoquinone, and 2,5-di-methyl-p-benzoquinone with vinyl monomers were studied. Reactions of p-chloranil with styrene yielded copolymers of approximately 1:1 composition under a variety of reaction conditions. A copolymer containing a block of 1:1 of styrene:p-chloranil and a block of polystyrene was prepared. Several styrene-like monomers copolymerized with p-chloranil to yield copolymrs possessing considerable amounts of incorporated quinone. p-Benzoquinone copolymerized with 1,3-butadiene and 2-vinyl-pyridine to yield copolymers of significant molecular weights. Reactions of 2,5-dimethyl-p-benzoquinone with vinyl monomers did not yield any isolable polymeric products.     

Polyanhydrides. I. Preparation of high molecular weight polyanhydrides

Polyanhydrides composed of the following diacids–sebacic acid, bis(p-carboxyphenoxy)propane, bis(p-carboxyphenoxy)hexane, isophthalic acid, 1,4-phenylene dipropionic acid, and dodecanedioic acid–were synthesized by a melt polycondensation process. Polymers of molecular weight up to 137,010 (weight average) and intrinsic viscosity of 0.92 dL/g were achieved. These high molecular weight polymers were reached by using pure isolated mixed anhydrides of diacids and acetic acid, under optimized reaction conditions (temperature of 180°C for 90 min under vacuum of 10^-4 mm Hg). Polymers of higher molecular weights were synthesized in shorter times by using heterogenic coordination catalysts: cadmium acetate, ZnEt₂-H₂O (1:1), barium oxide, calcium oxide, and calcium carbonate. By using these catalysts molecular weights of up to 245,000 were reached in 30 min of reaction. Films made of high molecular weight bis(p-carboxyphenoxy)propane–sebacic acid copolymers showed tensile strengths of 40–160 kg/cm²; the strength increased as a function of the bis(p-carboxyphenoxy)propane content and molecular weight.     

Olefin copolymerization with metallocene catalysts. I. Comparison of catalysts

A number of metallocene/methylaluminoxane (MAO) catalysts have been compared for ethylene/propylene copolymerizations to find relationship between the polymerization activities, copolymer structures, and copolymerization reactivity ratio with the catalyst structures. Stereorigid racemic ethylene bis (indenyl) zirconium dichloride and the tetrahydro derivative exhibit very high activity of 10 ⁷ g (mol Zr h bar)^?1, giving copolymers having comonomer compositions about the same as the feed compositions, molecular weights increasing with the increase of ethylene in the feed, random incorporation of comonomers, and narrow molecular weight distribution indicative of a single catalytic species. Nonbridged bis (indenyl) zirconium behaved differently, favoring the incorporation of ethylene over propylene, producing copolymers whose molecular weight decreases with the increase of ethylene in the feed, broad molecular weight distribution, and a methanol soluble fraction. This catalyst system contains two or more active species. Simple methallocene catalysts have much lower polymerization activities. C_pTiCl₂/MAO produced copolymers with tendency toward alternation, whereas Cp₂HfCl₂/MAO gave copolymer containing short blocks of monomers.     

Water-soluble copolymers. XII. Copolymers of acrylamide with sodium-3-acrylamido-3-methylbutanoate: Synthesis and characterization

The copolymerization of acrylamide (AM) with sodium-3-acrylamido-3-methylbutanoate (NaAMB) has been studied. The value of r₁r₂ has been determined to be 0.56 for the AM–NaAMB pair. The molecular weights of the copolymers were relatively unaffected by monomer feed ratios. The copolymer microstructures, including run numbers and sequence distributions, were calculated from the reactivity ratios. The solution properties of the AM–NaAMB copolymers, as well as the NaAMB homopolymer, will be reported in a subsequent paper.     

Studies on microstructure and aqueous solution properties of block copolymer of acrylamide-styrene

Three series of block copolymers of acrylamide (AM) and styrene (St) as hydrophobic comonomer with varied microstructures were prepared in microemulsion medium by changing feed ratio of monomers, ratio of St to surfactant, and amount of initiator, respectively. The effects of microstructure factors of the amphiphilic block copolymers PAM-b-PSt on their aqueous solution properties were investigated by fluorescence probe technique and surface tension measurement in detail. The experimental results show that the aqueous solution properties of PAM-b-PSt are strongly dependent on their microstructure factors, such as the length and content of PSt hydrophobic blocks in the copolymers and their molecular weight. It was found that the main microstructure factors which effect the hydrophobic association behavior of the copolymer PAM-b-PSt are the length and content of PSt hydrophobic blocks in the copolymer, whereas the hydrophobic association behavior of the copolymer is not affected nearly so much by molecular weight in more dilute regions. At the same time, it was also found that the main microstructure factors which affect the surface activity of the copolymer are the content of PSt hydrophobic blocks in the copolymer and molecular weight, whereas the length of PSt blocks in copolymer does not affect surface activity of the copolymer nearly so much under fixed content of PSt hydrophobic blocks and molecular weight in the copolymer.     

Inverse emulsion polymerization of acrylamide. II. Synthesis and characterization of copolymers with methacrylic acid

Inverse emulsion copolymerization studies of acrylamide (Am) with methacrylic acid (MAA) are reported. Aqueous monomer solutions were emulsified in toluene with a blend of two surfactants (sorbitan sesquioleate and C18-terminated acrylamide oligomers). Polymerization kinetics in presence of an oil-soluble initiator (AIBN) were determined at 40°C as a function of methacrylic acid content and aqueous-phase pH. Polymerization rates were found to be faster at basic pH than at acidic pH, which appeared to be related to the actual concentration of methacrylic acid in the aqueous phase. Monomer reactivity ratios have been derived as r_A-M = 0.58 ± 0.02 and r_M-A = 4.0 ± 0.10 at pH 4, r_A-M = 0.56 ± 0.005 and r_M-A = 0.15 ± 0.03 at pH 10. These differences were found to have an effect on the molecular characteristics of the copolymers. Initial emulsions and final inverse latexes displayed the same broad size distribution; under basic pH the particle size is relatively insensitive to the ionic comonomer concentration. Poor latex stability is characteristic of copolymer latexes prepared under acidic conditions. Based on these experimental results, some aspects of the polymerization mechanism are discussed.     

Dilute solution properties of poly(α-methylstyrene–ethylene) “regular” sequence copolymers

“Regular” sequence copolymers having the structure {[? CH₂? C(CH₃)(C₆H₅)? ]_m(CH₂? CH₂)_n}_p with relatively small values of m and n were prepared by means of “living” polymerization techniques. The intrinsic viscosities of fractions of these copolymers were obtained in various solvents including a theta solvent. The molecular weights of these fractions were determined by the Archibald ultracentrifugal method. The results show that the intrinsic viscosity–molecular weight relations of the regular sequence copolymers are affected not only by the average composition of the copolymer, but also by the sequence length in the copolymer molecule. It is suggested that the effective conformation of a chain element in the copolymer is not always the same as that in the homopolymer.     

新型疏水缔合丙烯酰胺/2-苯氧乙基丙烯酸酯共聚物的合成与性质

采用胶束共聚方法合成了一种新型的疏水缔合共聚物 ,它由丙烯酰胺 (AM)和少量的 2 苯氧乙基丙烯酸酯 (POEA) (<1 0mol% )组成 ,具有良好的水溶性 .当溶液浓度超过一定值c 后 ,由于分子间的疏水缔合 ,产生很大的增粘作用 .研究了不同聚合条件下包括单体浓度、投料比和SMR值对聚合物的结构和性能的影响 .实验结果表明 ,聚合物的粘度性质和缔合行为取决于其分子量的大小、疏水单体含量及其嵌段的长度和分布 .     

Synthesis and properties of polydimethylsiloxane-containing block copolymers via living radical polymerization

Polydimethylsiloxane (PDMS) block copolymers were synthesized by using PDMS macroinitiators with copper-mediated living radical polymerization. Diamino PDMS led to initiators that gave ABA block copolymers, but there was low initiator efficiency and molecular weights are somewhat uncontrolled. The use of mono- and difunctional carbinol–hydroxyl functional initiators led to AB and ABA block copolymers with narrow polydispersity indices (PDIs) and controlled number-average molecular weights (M_n's). Polymerization with methyl methacrylate (MMA) and 2-dimethylaminoethyl methacrylate (DMAEMA) was discovered with a range of molecular weights produced. Polymerizations proceeded with excellent first-order kinetics indicative of living polymerization. ABA block copolymers with MMA were prepared with between 28 and 84 wt % poly(methyl methacrylate) with M_n's between 7.6 and 35 K (PDI <1.30), which show thermal transitions characteristic of block copolymers. ABA block copolymers with DMAEMA led to amphiphilic block copolymers with M_n's between 9.5 and 45.7 K (PDIs of 1.25–1.70), which formed aggregates in solution with a critical micelle concentration of 0.1 g dm⁻³ as determined by pyrene fluorimetry experiments. Monocarbinol functional PDMS gave AB block copolymers with both MMA and DMAEMA. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1833–1842, 2001     

Effect of chemical structure on the properties of some hydrogels prepared by using gamma radiation polymerization

Several hydrogels were prepared using radiolytic polymerization of aqueous solutions of acrylamide or acrylamide containing appropriate comonomer such as acrylic acid, maleic acid, itaconic acid, and maleic anhydride. The hydrogels have been prepared at an irradiation dose of 30 kGy. The effects of the chemical structure of the monomer(s) and crosslinking agents on the yield of homopolymer(s) or copolymers have been studied. These crosslinking agents include N, N′‐methylene dimethacrylate (MDA) and N, N′‐methylene bisallyamide (MBA). The hydrogels obtained were characterized using swelling technique, thermal and spectroscopic analysis. The results obtained showed that the prepared samples are able to reject sodium ions and are not able to recover the Basic Blue Dye from their aqueous solution. © 2005 John Wiley & Sons, Ltd.     

Water-Soluble Copolymers. XIX. Copolymers of Acrylamide with Sodium 3-(N-Propyl)acrylamido-3-Methylbutanoate: Synthesis and Characterization

The copolymerization of acrylamide (AM) with sodium 3-(N-propyl)acrylamido-3-methlbutanoate (NaPAMB) has been studied in the range from 40 to 90% AM in the feed. The copolymer compositions have been determined from elemental analysis and ¹³C NMR. Reactivity ratio studies have been performed, and the value of r₁r₂ determined to be 0.36. The molecular weights, as determined by low-angle laser light scattering of the copolymers, were found to decrease sharply with increasing NaPAMB content, and were in the range 0.5–7.0 × 10⁶. The copolymer microstructures, including mean sequence length distributions, were calculated from the reactivity ratios. Knowledge of polymer composition, micro-structure, and molecular weight is utilized for assessment of structure/dilute solution property relationships reported in a subsequent paper in this series.     

Synthesis and radical polymerization of styrene derivative bearing kojic acid moieties

A styrene derivative ( 1 ) bearing kojic acid moieties was prepared by the base-catalyzed reaction of p-formylstyrene with kojic acid. Hydroxyl groups in 1 were subjected to acetylation. Although 1 did not undergo radical polymerization, the acetylated styrene derivative ( 2 ) showed good radical homo- and copolymerizability. For instance, a polymer having the number average molecular weight (M_n) of 60,000 was obtained in almost quantitative yield (97%) by the polymerization of 2 in chloroform (1.5 M) at 60°C for 36 h using α,α′-azobis(isobutyronitrile) (AIBN, 5 mol %) as an initiator. Under similar conditions, copolymers of 2 with styrene were also obtained in high yield. By partial deacetylation of the copolymer with a triethylamine catalyst, a copolymer containing α-hydroxyketone structures originated from kojic acid moieties was successfully regenerated. The deacetylated copolymer can be crosslinked by complexation with metal salts such as Al³⁺. © 1996 John Wiley & Sons, Inc.     

Water-soluble copolymers. XLII. Cationic polyelectrolytes of acrylamide and 2-acrylamido-2-methylpropanetrimethylammonium chloride

The new monomer 2-acrylamido-2-methylpropanetrimethylammonium chloride (AMP-TAC, M₂) has been synthesized. Free radical copolymerization with acrylamide (AM, M₁) in feed ratios varying from 10 to 50 mol % AMPTAC gave the cationic ATAM series. Copolymer compositions were determined from ¹³C-NMR. The reactivity ratio product r₁r₂ was found to be 0.62. Molecular weights varied from 1.4 to 16.5 × 10⁶ g/mol for the copolymers. Turbidimetric studies showed aqueous solutions of the copolymers to be phase stable in the presence of CaCl₂ and Na₂CO₃ up to 100°C. Solution behavior was independent of pH in the range of 3 to 11, and temperature in the range of 25 to 60°C. Intrinsic viscosities of the cationic copolymers decreased with the addition of electrolytes; however, some samples showed curvature in plots of intrinsic viscosity versus the inverse square root of ionic strength. © 1993 John Wiley & Sons, Inc.     

Base-catalyzed polymerization of maleimide and some derivatives and related unsaturated carbonamides

Basic catalysts in dimethylacetamide solution initiated the polymerization of maleimide to yield a low molecular weight polymer which has a copolymer structure. Approximately 75–85% of the recurring units are formed by hydrogen transfer and 15–25% by vinyl polymerization, as shown by hydrolysis, to yield aspartic acid on the one hand and ammonia and polymaleic acid on the other. Several maleimide derivatives have been prepared, but none has given a high molecular weight polymer by basic catalysis. Some unsaturated carbonamides such as p-vinylbenzamide, mono-N-acrylyl-hexamethylenediamine, and mono-N-acrylyl-p-phenylenediamine have been synthesized and polymerized by basic catalysts. Polymers with low molecular weights were obtained, but the complete structures of all these polymers were not established.     

温敏两亲性接枝物PAM-g-PNIPAm的合成及表征

以巯基乙胺为分子量调节剂,以丙烯酰氯作为链端转化剂合成了不同分子量的端丙烯酰胺基聚(N-异丙基丙烯酰胺)(PNIPAm)大分子单体;与丙烯酰胺共聚合,合成了以PNIPAm为侧链的接枝聚丙烯酰胺.用FTIR和¹HNMR方法表征了接枝聚合物与大分子单体的组成.该接枝聚合物在水溶液中具有热缔合特性及明显的温敏增稠性,水溶液的粘度在32～50℃之间随温度增加而增加.     

Synthesis,characterization, and properties of copolymer of acrylamide and complex pseudorotaxane monomer consisting of cucurbit[6]uril with butyl ammonium methacrylate

The novel copolymers of acrylamide (AM) with complex pseudorotaxane monomer (BAMACB) of butyl ammonium methacrylate (BAMA) and cucurbit[6]uril (CB[6]) were prepared via free‐radical polymerization in aqueous solution. The copolymers containing pseudorotaxane (PAM/BAMACB) were characterized by ¹H‐NMR, FTIR, elemental analysis, TGA, and DSC. The glass transition temperature (T_g) of the copolymer PAM/BAMACB are higher than that of the copolymer of acrylamide and butyl ammonium methacrylate (PAM/BAMA) because of the enhanced rigidity and the bulky steric hindrance of BAMACB side chain in PAM/BAMACB. The molecular weights of copolymer PAM/BAMACB were obtained via static light scattering. The hydrodynamic radii of coils or aggregates were investigated by dynamic light scattering. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5999–6008, 2008     

Synthesis and Characterization of Hybrid Biopolymers of L-lactic Acid and 2-Pyrone-4,6-dicarboxylic Acid

Copolymers of L-lactic acid (LA) and 2-pyrone-4,6-dicarboxylic acid (PDC), a chemically stable metabolic intermediate of lignin, were prepared by dehydrated polycondensation based on stepwise oligomerization followed by post-polymerization in vacuo. When the polymerization was performed in the presence of methanesulfonic acid as a catalyst, the molecular weights of the resulting copolymers were sufficiently high. Furthermore, expansion of the polymeric surface area was found to be an important factor in facilitating dehydration and thereby producing high molecular weight polymers. PDC feed ratio significantly affected the molecular weight because of the different polymerization capability from LA. Relationship between the PDC feed ratio and the molecular weight of the resulting polyesters was for the first time demonstrated quantitatively. The obtained copolymers were characterized by ¹H- and ¹³C-NMR, IR, and thermal analysis. The high molecular weight copolymers possessed the higher decomposition temperatures than PLLA and their fusible temperature ranges were reasonably expanded.     

Water-soluble copolymers. X. Copolymers of acrylamide with N-(1,1-dimethyl-3-oxybutyl)acrylamide and N,N-dimethylacrylamide: Solution properties

Dilute solution properties of copolymers of acrylamide (AM) with N-(1,1-dimethyl-3-oxybutyl)acrylamide (DAAM) and with N,N-dimethylacrylamide (DMAM) have been studied as a function of composition, temperature, time, and added electrolytes sodium chloride and calcium chloride. Unlike the AM-DMAM copolymers, the AM-DAAM copolymers show solution viscosity increases in the presence of added NaCl and CaCl₂ and decreases with increasing temperature which are related to copolymer composition. The unusual viscosity behavior of the DAAM-AM copolymers is suspected to be due to chain extension resulting from intramolecular hydrogen bonding and other cooperative associations along the macromolecular backbone.     

Effect of monomer functional groups on the composition of some three component random phenolic copolymers

Some three-component random phenolic copolymers were prepared from three typical phenolic monomers; for example, p-chlorophenol, p-aminophenol, and p-cresol. Several samples of the copolymer were prepared by changing the feed composition and the composition of the copolymers was established by estimating ? NH₂ and ? OH groups by electrometric titration techniques in nonaqueous media. Halogen was estimated by Volhard's method. The average degree of polymerization (DP) of the copolymers was calculated from the features of the electrometric titration curves, and the effects of monomer functional groups on the composition of the copolymers were interpreted in terms of the electron-donating and electron-attracting nature of the substituents present in the monomers.     

Microstructure and association property of hydrophobically modified polyacrylamide of a new family

A new family of hydrophobically modified polyacrylamides was synthesized via copolymerization of acrylamide (AM) and anionic surface-active monomer of acrylamide-type, sodium 2-acrylamido-tetradecane sulfonate (NaAMC₁₄S), in aqueous solution. In the copolymerization, by varying various factors, such as the feed ratio of NaAMC₁₄S to AM and the amount of added electrolyte NaCl and initiator, we prepared copolymers NaAMC₁₄S/AM with different block structures. The relationship between structures and hydrophobic association properties of copolymer chains was studied by using fluorescence probe and viscosimetry. Effects of the content and length of the hydrophobic blocks and the total molecular weight on hydrophobic association of the copolymers in pure water and in brine solution were examined, respectively. The results show that in pure water, hydrophobic association of the copolymers was enhanced as the content and length of the hydrophobic block increase. On the other hands, for a given content and length of the hydrophobic block, the hydrophobic association of the copolymers was enhanced as the total molecular weight increases. For all the copolymers studied, the apparent viscosity of their solutions in pure water has a limited value, but the apparent viscosities of the copolymer brine solutions are much higher than that of their corresponding water solutions, and show strong positive salinity sensitivity. Similarly, the hydrophobic association of the copolymer in brine solutions was enhanced as the content and length of the hydrophobic block increase.