Linear‐dendritic copolymers as nanocatalysts

Functionalized poly(ethylene glycol) (PEG) containing four chloride end functional groups (PEG‐Cl₄) was synthesized through reaction between cyanuric chloride and PEG‐(OH)₂. Chloride end functional groups of PEG‐Cl₄ were able to initiate the ring opening polymerization of 2‐ethyl‐2‐oxazoline and star copolymers containing a PEG core, and poly(2‐ethyl‐2‐oxazoline) (POX) arms were obtained. Polymerization was quenched using diethanolamine, and star copolymers containing hydroxyl end functional groups (PEG‐POX‐OH) were obtained. ε‐Caprolactone was then polymerized using the hydroxyl end functional groups of star copolymers and amphiphilic linear‐dendritic copolymers containing PEG and POX, and poly(caprolactone) (PCL) blocks were synthesized. Linear‐dendritic copolymers were able to load the organic and inorganic guest molecules. Application of host‐guest systems such as nanocatalyst for Heck chemical reaction was also investigated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Cyanuric acid–epichlorohydrin prepolymers

In this study, we investigated the reaction of cyanuric acid and epichlorohydrin (ECH). SnCl₄ was used as a catalyst. Several reaction conditions were tested, and the products were analyzed by means of Fourier transform infrared and ¹H‐NMR spectroscopy, hydroxyl group content, molar mass, elemental and thermal analysis, viscosity, and density. ECH reacted with the amine groups of the cyanuric acid ring to form lateral chains that contained chloroalkyl and hydroxyl end groups. Full substitution of the amine groups was observed in all of the synthesized products. The solvent used in the synthesis was found to be very important for the structure of the final prepolymers. When N,N‐dimethylformamide was used, relatively low‐molar‐mass prepolymers of cyanuric acid and ECH were obtained. When solvents with low dielectric constants were used, no reaction with cyanuric acid was observed. The prepared prepolymers were thermally stable up to 160°C. At this temperature, degradation started via the lateral chains. The viscosity of the products decreased as the ECH–cyanuric acid ratio increased, whereas the density remained basically constant. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3684–3691, 2006     

Synthesis and characterization of triazine‐based dendrimers and their application in metal ion adsorption

This article described the synthesis of triazine‐based dendrimers with poly(ethylene glycol) core by convergent method. Compound 1 was prepared by coupling of amino group of diethanolamine with cyanuric chloride in dry THF (tetrahydrofuran). Reaction of compound 1 with p‐aminobenzylamine resulted in compound 2 . Compound 4 was synthesized using coupling reaction of amino group of compound 2 with cyanuric chloride, then coupling of amine groups of p‐aminobenzylamine with compound 3 in the hybrid solvents. The final dendrimer (den‐OH) were synthesized using reaction of dendron 4 with compound 5. Ethylene diaminetetraacetic acid modified final dendrimer were successfully prepared via coupling ethylene diaminetetraacetic acid dianhydride and den‐OH. The growth of dendrons and their structures were investigated by using usual spectroscopy methods and elemental analysis. The chelating behavior and sorption capacities of triazine dendrimers were determined in relation to pH dependency for some metal ions such as Cu⁺², Ni⁺², and Zn⁺² using atomic absorption methods. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Imparting insect repellency to nylon 6 fibers by means of a novel MCT reactive dye

Insect repellency of fiber is a property which makes the fiber to be of interest in the field of military and health. The insect‐repellent substrate could be prepared using either functional finishing or applying an insect‐repellent dye. In this article, insect‐repellent nylon 6 is obtained using a novel insect‐repellent reactive dye containing N,N‐diethyl‐m‐toluamide. To do this, N,N‐diethyl‐m‐toluamide (DEET) was first nitrated at the p‐position relative to amide functionality. The nitrated product was reduced in the presence of C₂H₅OH, SnCl₂, and HCl. The produced amine was then condensed with 2,4,6‐trichloro‐1,3,5‐triazine (cyanuric chloride) as a reactive group in below 5°C. The resultant adduct was finally reacted with an amino group present in 6‐amino‐1‐hydroxy naphthalene‐3‐sulfonic acid (J‐acid) to produce 7‐(4‐chloro‐6‐(4‐(diethylcarbamoyl)‐2‐methylphenylamino)‐1,3,5‐triazin‐2‐ylamino)‐4‐hydroxynaphthalene‐2‐sulfonic acid. To synthesis azo dye, sulfanilic acid was diazotized using HCl and NaNO₂ and then coupled to the above prepared component to produce insect‐repellent reactive dye. An analog dye was prepared via the same route without insect‐repellent group making stage. The chemical structures of the novel dyes were characterized using FTIR and ¹H‐NMR spectroscopy. The spectroscopic properties of the dyes were determined in terms of λ_max and ε_max in aqueous solution. The novel dyes were then reacted with nylon 6 and bonded to it covalently to provide permanent insect‐repellent substrate. The insect‐repellent efficacy of the reacted nylon 6 was studied using standard methods for Anophele mosquito repellent. The insect‐repellent dye reacted nylon 6 showed insect‐repellent activity. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis of pentavalent imidovanadium complexes and their catalyses for the polymerization of ethylene and propylene

Imidovanadium complexes with cyclopentadienyl (Cp) ligands—(Cp)V(?NC₆H₄Me‐4)Cl₂ (1), (Cp)V(?N^tBu)Cl₂ (2), and (^tBuCp)V(?N^tBu)Cl₂ (3; ^tBuCp = tert‐butylcyclopentadienyl)—were synthesized through the reaction of imidovanadium trichloride with (trimethylsilyl)cyclopentadiene derivatives. The molecular structure of 3 was determined by X‐ray crystallography. The monocyclopentadienyl complex 1 exhibited moderate activity in combination with methylaluminoxane [MAO; 10.3 kg of polyethylene (mol of V)^?1 h^?1 atm^?1], whereas similar complexes with bulky ^tBu groups, 2 and 3, were less active. (2‐Methyl‐8‐quinolinolato)imidovanadium complexes, V(?NR)(O ?N)Cl₂ (R = C₆H₃ⁱPr₂‐2,6 (4) or n‐hexyl (5), O ?N = 2‐methyl‐8‐quinolinolato), were obtained from the reaction of imidovanadium trichloride with 2‐methyl‐8‐quinolinol. Upon activation with modified MAO, complex 4 showed moderate activities for the polymerization of ethylene at room temperature. The complex 5/MAO system also exhibited moderate activity at 0°C. The polyethylenes obtained by these complexes had considerably high melting points, which indicated the formation of linear polyethylene. Moreover, the 5/dried MAO system showed propylene polymerization activities and produced polymers with considerably high molecular weights and narrow molecular weight distributions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1008–1015, 2005     

Effect of reactivity of different types of hydroxyl groups of HTPB on mechanical properties of the cured product

The amount of three types of hydroxyl functional groups (G_OH, H_OH, and V_OH) in hydroxyl terminated polybutadiene (HTPB), remaining in samples acetylated to the same extent under two different conditions, viz., fast acetylation using acetyl chloride in presence of N-methyl imidazole catalyst and slow acetylation by acetic anhydride, differed significantly. For the fast acetylation there is a uniform reduction in all the three types of hydroxyls, probably because the reaction becomes random at rapid rates and the reactivity of the different types of hydroxyls does not play a major role. However, in the slow reaction, the reduction of G-type hydroxyls was 30% more than the expected value and there was a corresponding increase in the amount of V-type hydroxyls remaining in the acetylated product, showing reactivity of OH in the order of G > H > V. When the reaction is slow, it becomes selective and the change in reactivity of the three types of OH groups is reflected in the extent of conversion. The mechanical properties and the crosslink density data show a reduction in the samples containing lesser amounts of G_OH, confirming the branching nature of G_OH, which is involved in the crosslinking reaction. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1313–1320, 1997     

Synthesis of polypropylene graft copolymers from a hydroxyl‐groups‐containing polypropylene precursor via atom‐transfer radical polymerization

Isotactic polypropylene graft copolymers, isotactic[polypropylene‐graft‐poly(methyl methacrylate)] (i‐PP‐g‐PMMA) and isotactic[polypropylene‐graft‐polystyrene] (i‐PP‐g‐PS), were prepared by atom‐transfer radical polymerization (ATRP) using a 2‐bromopropionic ester macro‐initiator from functional polypropylene‐containing hydroxyl groups. This kind of functionalized propylene can be obtained by copolymerization of propylene and borane monomer using isospecific MgCl₂‐supported TiCl₄ as catalyst. Both the graft density and the molecular weights of i‐PP‐based graft copolymers were controlled by changing the hydroxyl group contents of functionalized polypropylene and the amount of monomer used in the grafting reaction. The effect of i‐PP‐g‐PS graft copolymer on PP‐PS blends and that of i‐PP‐g‐PMMA graft copolymer on PP‐PMMA blends were studied by scanning electron microscopy. Copyright © 2006 Society of Chemical Industry     

Hydrogenation of low‐molar‐mass,OH‐telechelic polybutadienes. II. Nuclear magnetic resonance and infrared spectrometric determination of hydroxyl end groups before and after hydrogenation by diimide

¹H nuclear magnetic resonance (¹H‐NMR), ¹³C‐NMR, and infrared spectroscopies were used to determine concentrations (c_OH, in mmol/g) of the secondary hydroxyl end groups in the low‐molar‐mass, OH‐telechelic polybutadienes, and their hydrogenated analogs. Mean OH‐functionality (f_OH ≤ 2), that is, an average number of OH groups per one polymer chain, was calculated from c_OH for each sample and each method, and the results were compared with those obtained by a conventional acetic anhydride titration method. It has been found that with molar masses of the samples studied (2310 to 3410 g/mol), the differences between individual spectrometric methods are usually not higher than approximately 10%, which corresponds to an expected relative experimental error. Certain differences in f_OH between individual methods are discussed. No systematic change of f_OH after virtually total hydrogenation of the olefinic double bonds of the polymeric substrate by diimide was observed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3214–3224, 1999     

Preparation and degradability of poly(lactic acid)–poly(ethylene glycol)–poly(lactic acid)/SiO2 hybrid material

Poly(lactic acid)–poly(ethylene glycol)–poly(lactic acid) (PLA‐PEG‐PLA)/SiO₂ hybrid material is prepared by sol–gel method using tetraethoxysilane (TEOS) and PLA‐PEG‐PLA as raw material. From Fourier transform infrared spectroscopy (FTIR) and X‐ray photoelectron spectroscopy (XPS) spectra, the hydroxyl groups of the silica sol derived from partially hydrolysis of TEOS and the unhydrolyzed ethoxy groups of TEOS can react with PLA‐PEG‐PLA. Differential scanning calorimetry (DSC) curves imply that the glass transition temperature (T_g) of PLA‐PEG‐PLA/SiO₂ hybrid material is higher than that of PLA‐PEG‐PLA and increases with the increase of silica content. X‐ray diffraction (XRD) analysis results show that PLA‐PEG‐PLA and PLA‐PEG‐PLA/SiO₂ hybrid material are both amorphous. Field scanning electron microscope (FSEM) photographs show that when PLA‐PEG‐PLA/SiO₂ hybrid material has been degraded for 12 weeks in normal saline at 37°C, a three‐dimensional porous scaffold is obtained, which is available for cell growth and metabolism. Moreover, the hydroxyl (? OH) groups on SiO₂ of PLA‐PEG‐PLA/SiO₂ hybrid material could buffer the acidity resulted from the degradation of PLA, which is beneficial to proliferation of cell in tissue repairing. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and gas permeation parameters of metathesis polytricyclononenes with pendant Me3E‐groups (E = C,Si, Ge)

Metathesis polytricyclononenes were synthesized via ROMP polymerization in the presence of the 1‐st generation Grubbs catalyst and their gas‐transport properties were studied for the first time. The aim of this work was to evaluate the influence of Me₃E‐groups (E = C, Si, Ge) on gas permeation parameters of ROMP materials. New metathesis poly(3‐tert‐butyltricyclononene‐7) and poly(3‐trimethylgermyltricyclononene‐7) were obtained with high yields (up to 95%) and high‐molecular weights (M_w～3–7×10⁵ g mol^?1). The glass transition temperatures of the ROMP polytricyclononenes with Me₃E‐groups decreased when E was changed from C to Si and then to Ge. It was shown that the polytricyclononene containing Me₃Si‐groups has the highest gas permeability while the polytricyclononene containing Me₃C‐substituents has the lowest gas permeability. In addition, the gas permeation parameters were estimated for ROMP Me₃Si‐ and Me₃Ge‐substituted polytricyclonona‐3,7‐dienes. So the influence of the second double bond in the monomer units on the permeability of the polymers obtained was studied. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41395.     

Synthesis of barbell-like triblock copolymers, dendritic triazine-block-poly(ethylene glycol)-block-dendritic triazine and investigation of their solution behaviors

New bis-globular triblock copolymers containing poly(ethylene glycol) (PEG) as a core and triazine dendrons were synthesized. First generation (G₁) was prepared by coupling of hydroxyl group of poly(ethylene glycol) with cyanuric chloride in different solvents through two routes, in the first route reaction was carried out in the presence of sodium hydride in dry DMF at low temperature and in another route water solution of sodium hydroxide in dichloromethane solvent was used. Reaction of compound G₁ with amino group of diethanolamine in dichloromethane resulted G_1.5. Second generation of linear-dendritic compounds (G₂) was synthesized using coupling reaction of hydroxyl groups of compound G_1.5 and 1 (compound 1 was prepared by reaction of cyanuric chloride with phenol in the presence of sodium hydroxide). Growth of dendrons on the PEG core and their structure was investigated using usual spectroscopy methods, SEC and CHN analysis. Critical micelle concentration and probable conformations of linear-dendritic compound G₂ was investigated using fluorescence and NMR spectroscopy in different solvents.     

Hyperbranched homo and thermoresponsive graft copolymers by using ATRP‐macromonomer initiators

Macromonomer initiators behave as macro cross‐linkers, macro initiators, and macromonomers to obtain branched and cross‐linked block/graft copolymers. A series of new macromonomer initiators for atom transfer radical polymerization (MIM‐ATRP) based on polyethylene glycol (M_n = 495D, 2203D, and 4203D) (PEG) were synthesized by the reaction of the hydroxyl end of mono‐methacryloyl polyethylene glycol with 2‐bromo propanoyl chloride, leading to methacryloyl polyethylene glycol 2‐bromo propanoyl ester. Poly (ethylene glycol) functionalized with methacrylate at one end was reacted with 2‐bromopropionyl chloride to form a macromonomeric initiator for ATRP. ATRP was found to be a more controllable polymerization method than conventional free radical polymerization in view of fewer cross‐linked polymers and highly branched polymers produced from macromonomer initiators as well. In another scenario, ATRP of N‐isopropylacrylamide (NIPAM) was initiated by MIM‐ATRP to obtain PEG‐b‐PNIPAM branched block/graft copolymers. Thermal analysis, FTIR, ¹H NMR, TEM, and SEM techniques were used in the characterization of the products. They had a thermo‐responsive character and exhibited volume phase transition at ～ 36°C. A plasticizer effect of PEG in graft copolymers was also observed, indicating a lower glass transition temperature than that of pure PNIPAM. Homo and copolymerization kinetics were also evaluated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Selective Iron‐Catalyzed Oxidation of Benzylic and Allylic Alcohols

A convenient and selective oxidation of alcohols with hydrogen peroxide to give aldehydes and ketones has been developed. Using in situ generated iron chloride complexes [Fe( L3 )₂Cl_n] [n=0–1, L3 =6‐(N‐phenylbenzimidazoyl)‐2‐pyridinecarboxylic acid], aldehydes and ketones were obtained in good yield and excellent selectivity after a short reaction time at room temperature.     

New self‐crosslinkable copolymers based on N‐methyl‐N‐vinylbenzylpyrrolidinium halide and methyl methacrylate

Thermally‐induced self‐crosslinking behaviour has been found in copolymers containing N‐methyl‐N‐vinylbenzylpyrrolidinium chloride (MVBPC) and methyl methacrylate (MMA). NMR, IR and low molecular weight model reactions demonstrate that this crosslinking reaction occurs between the methyl ester groups of the MMA units and the quaternary ammonium salts, with the resulting benzyl esters forming chemical links between the MVBPC and MMA units with the formation of N,N‐dimethylpyrrolidinium chloride. Similar crosslinking behaviour has also been found when the Cl⁻ anion is replaced by Br⁻ and I⁻, but not in the case of BF as counter anion. © 2000 Society of Chemical Industry     

Cationic starch iodophores

Cross‐linked cationic starches N‐(2‐hydroxyl)propyl‐3‐trimethyl ammonium starch chloride (CQS chloride), N‐(2‐hydroxyl)propyl‐3‐trimethyl ammonium starch iodide (CQS iodide), and N‐(2‐hydroxyl)propyl‐3‐trimethyl ammonium starch iodide–iodine (CQS triiodide) with the degree of substitution (DS) according to cationic groups from 0.04 to 0.62, as well as cross‐linked starch–iodine complexes were synthesized and tested as potential antibacterial agents. Cationic starch iodine derivatives were obtained during ion exchange reaction between CQS chloride and iodide or iodide–iodine anions in aqueous solutions. CQS_DS≤0.3 chloride can form several types of iodine complexes, such as the blue amylose–iodine inclusion complex and ionic CQS⁺I^?·(I₂)_m complex (m ≥ 1). The antibacterial activity of modified starches–iodine samples against different pathogenic bacterial cultures and contaminated water microorganisms was evaluated. CQS chloride and CQS iodide were found to be bacteriostatic. A strong antibacterial activity was characteristic of CQS triiodides in which molecular iodine is present in both ionic and inclusion complexes. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

The isolation and characterization of lignin of kenaf fiber

In this article, milled wood lignin (MWL) was isolated and purified from retted kenaf fiber, the lignin obtained was characterized by elemental analysis, FTIR, ¹H‐NMR, and ¹³C‐NMR spectroscopy. The C₉ formula is calculated for kenaf fiber MWL as C₉H_9.32O_3.69(OCH₃)_1.30. The spectra of FTIR, ¹H‐NMR, and ¹³C‐NMR show the kenaf fiber lignin to be of the G/S type with high proportion of syringyl (S) unit. The numbers of phenolic and aliphatic hydroxyl groups in the kenaf fiber MWL are estimated to be 0.14 and 1.31, respectively, per C₉ unit. The OH_aliph is 90.3% in total numbers of hydroxyl groups of kenaf fiber MWL, and the OH_ph is 9.7%. It is evident that the β‐O‐4 structures are mainly linkage in the MWL of kenaf fiber, which contain more erythro stereochemistry type in β‐O‐4 units than thero stereochemistry type. In general, the characteristics of lignin of kenaf fiber are similar to that of hardwood. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The Synthesis and Characterization of s-Triazine-Cored and [Fe(III)Salen]-Capped Polymer Complexes

2,4,6-Trichloro-1,3,5-triazine (cyanuric chloride, C₃N₃Cl₃, 1) was used as the starting material. 2-(4-Carboxyphenylamino)-4,6-dichloro-1,3,5-triazine (2) was obtained from the reaction of cyanuric chloride with 4-aminobenzoic acid in the presence of sodium bicarbonate in acetone. A mononuclear complex (4) was obtained by reacting 2 and [FeSalen]₂O (3). A series of polymeric compounds was obtained by reacting 4 with a series of diamines. The polymeric complexes were characterized by elemental analysis, AAS, FT-IR, ¹H NMR, TGA and magnetic susceptibility measurements. The complexes are low-spin, distorted octahedral Fe(III) species that are bridged by carboxylic acids. The [FeSalen]-containing compounds may have the electronic structure t_2g⁵e_g⁰. All the complexes have six coordination and are polymeric.     

Immobilization of poly(ethylene oxide) on poly(ethylene terephthalate) using a plasma polymerization process

Poly(ethylene oxide) (PEO) has been covalently immobilized on poly(ethylene terephthalate) (PET) films using a radio frequency glow discharge polymer deposition process, followed by chemical coupling. Amino or hydroxyl groups were introduced onto the surface of the PET by exposing the films to allylamine and allyl alcohol plasmas. These functional groups were activated with cyanuric chloride, and then they were reacted with PEO. ESCA and water contact angle studies were used to characterize the surfaces of these films during the different stages of the reaction. The films containing the higher molecular weight PEO exhibited an increase in the ? C? O? peak of the C_ls ESCA spectrum and an increase in oxygen content on the film surfaces. Increasing the molecular weight of the PEO attached to the PET also resulted in an increased wettability of the films.     

Synthesis of fluorescent ABA triblock copolymer via click reaction

A hyperbranched–linear–hyperbranched (ABA) triblock copolymer containing poly(ethylene glycol) (PEG) as linear block and polyglycerol (hbPG) as hyperbranched blocks has been synthesized through a copper‐catalysed click reaction. In order to synthesize the hyperbranched block, propargyl alcohol‐initiated ring‐opening multibranching polymerization of glycidol was used to prepare hbPG with the propargyl segment in the focal point (CH?C? hbPG). Separately, PEG was functionalized at both ends using cyanuric chloride, and then the chloride groups of cyanuric chloride were substituted by azide groups. Finally, the azide‐functionalized PEG was conjugated to CH?C? hbPG via a click reaction. Substitution of the chlorine atoms of cyanuric chloride under different conditions together with click chemistry allows the synthesis of a variety of polymeric architectures. In the last step, fluorescein was attached to the block copolymer as a fluorescent probe in order to study the cell internalization of this copolymer. This type of triblock copolymer is a promising future nanomaterial for simultaneous drug delivery and cell imaging. © 2016 Society of Chemical Industry     

A novel method of hyperbranched poly(amide‐ester) modifying nano‐SiO2 and study of mechanical properties of PVC/nano‐SiO2 composites

A new method of surface chemical modification of nano‐SiO₂ was proposed in the paper. In the presence of catalyst, the active hydroxyl groups on the surface of nano‐SiO₂ reacted with AB₂‐type monomer (N,N‐dihydroxyethyl‐3‐amino methyl propionate) by one‐step polycondensation. And the product's Fourier transform infrared graphs and transmission electron microscopy (TEM) images proved that hyperbranched poly(amine‐ester) (HPAE) was grafted from nano‐SiO₂ surface successfully. Moreover, polyvinyl chloride (PVC)/modified nano‐SiO₂ composites were made by melt‐blending. The composites' structures and mechanical properties were characterized by TEM, scanning electron microscopy, and electronic universal testing machine. The results showed that nano‐SiO₂ grafted by HPAE increased obviously in dispersion in PVC matrix, and mechanical properties of PVC were effectively improved. Additionally, it was found that mechanical properties of PVC/nano‐SiO₂ composites reached the best when weight percent of nano‐SiO₂ in PVC matrix was 1%. Compared with crude PVC, the tensile strength of HPAE grafted nano‐SiO₂/PVC composite increased by 24.68% and its break elongation, flexural strength, and impact strength increased by 15.73, 4.07, and 184.84%, respectively. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers