Studies on synthetic polymer plates with high surface energy. III. Diethylene glycol bis(allyl carbonate)–unsaturated sulfonic acid system

Synthetic polymer plates (GPs) with high surface energy were prepared by the two-step copolymerization process previously reported, using diethylene glycol bis(allyl carbonate) (CR-39) as M₁ monomer and unsaturated sulfonates [sodium vinyl sulfonate (VS^?Na⁺), potassium styrene sulfonate (StS^?K⁺), and sodium 2-sulfoethyl methacrylate (SEM^?Na⁺)] as M₂ monomer. The contact angle (θ_H) of water for the acid-treated (immersed in an aqueous 0.1 N HCl solution for 2 h) GPs decreased in the order StS^?K⁺, VS^?Na⁺, and SEM^?Na⁺. In the case of M₂ = SEM^?Na⁺, the θ_H value was about 20°. By adding NaCl in the immersion solution and changing the pH of the immersion solution, the θ_H values for the CR-39–SEM^?Na⁺ GPs were lowered to 18.9 and 13.1°, respectively. The θ_H values for the above GPs were smaller than those for the CR-39–acrylic acid or the CR-39–methacrylic acid GPs in the previous report, whereas the contact angle (θ_Na) of water for the former after alkali treatment (immersed in an aqueous 0.1 N NaOH solution for 2h) was larger than those for the latter. The former had durability of water wettability superior to the latter because of the difference in dissociation characteristic of the respective functional group.     

Studies on synthetic-polymer plates with high surface energy. V. Diethylene glycol bis(allyl carbonate)–acrylic acid copolymer plate by vapor-phase transfer process

Synthetic-polymer plates with carboxyl group on their surface were prepared by a two-step copolymerization process transferring M₂ monomer via vapor phase. Diethylene glycol bis(allyl carbonate) (CR-39) was used as M₁ monomer, and acrylic acid was acid was used as M₂ monomer. The relations between the experimental conditions and the surface properties of the resulting plates were examined in the following terms: (1) composition of CR-39 prepolymer gel plate used and (2) concentration of benzoyl peroxide as the initiator. The plates had good water wettability and an excellent antifogging property.     

Studies on synthetic polymer plates with high surface energy. I. Diallyl phthalate-unsaturated carboxylic acid system

A new preparation technique of the polymer plate with high water wettability and sufficient mar resistance was proposed. The gel plate resulting from the prepolymerization of diallyl compound (M₁), diallyl phthalate (DAP), in a casting cell was immersed in an aqueous solution of unsaturated carboxylic acid (M₂), acrylic acid (AA), and methacrylic acid (MAA), at a specific temperature for a specific time. M₂ was copolymerized with the remaining M₁ in the region near the surface of the gel plate, and polymer plates with the following characteristics were obtained: for DAP–AA system, θ_i (contact angle of the alkali-treated plate) = 10.5° and mar resistance (for the alkali-treated plate at a dry state) = 70 g; for DAP–MAA system, θ_i = 8.3°, and mar resistance = 65 g.     

Studies on synthetic-polymer plates with high surface energy. IV. Determination of critical surface tension with aqueous solutions of salts

The critical surface tension (γ_c) of synthetic-polymer plates with a functional group (amide, sulfonic, or carboxyl group) on their surface was determined by the Zisman plot using series of pure liquids (thiodiglycol, formamide, and water) and the aqueous solutions of the salts (NaCl, NaNO₃, etc.) as a hydrogen-bonding liquid. The Zisman plots gave a straight line, and the trends in the γ_c values coincide with those in the hydrophilicity anticipated from the θ values. The use of the aqueous salt solution coupled with the pure liquids as a hydrogen-bonding liquid offers a practical determination procedure of the γ_c value for the materials with high surface energy.     

Studies on the light-focusing plastic rod. IX. Chemical composition of the copolymer rod-diethylene glycol bis(allyl carbonate) with 2,2,3,3-tetrafluoropropyl methacrylate

For the preparation of the light-focusing plastic rod (LFR) a gel rod of partially polymerized diethylene glycol bis(allyl carbonate) (CR-39) was immersed in 2,2,3,3-tetrafluoropropyl methacrylate (4FMA) followed by heat treatment under nitrogen. Variations in the chemical composition in this process indicated the following mode of copolymerization: copolymerization of 4FMA with the allylic group in the gel rod occurs to some extent in the immersion process, but a significant amount of either 4FMA or CR-39 remains in the rod. Under heat treatment, these monomers copolymerize to a CR-39–4FMA network copolymer, the preferential component of the LFR. Excellent imaging of the representative LFR is also demonstrated.     

Evaluation of the diethylene glycol bis(allyl carbonate)/acrylic acid copolymer behavior by solid‐state 13C‐NMR

The dynamic behavior of diethylene glycol bis(allyl carbonate) (CR‐39)/acrylic acid (AA) copolymers was evaluated by ¹³C high‐resolution solid‐state nuclear magnetic resonance (NMR). The NMR data showed that the copolymerization of CR‐39 and AA generated copolymers with different molecular behaviors as a function of AA content, which promoted changes in the crosslinking of CR‐39 chains and in the intramolecular forces. The copolymerization process influenced the sequence distribution and domain formation of the monomers, which is a consequence of the dispersion of comonomers along the macromolecular chains. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 740–745, 2005     

Biocompatible,ionic‐strength‐sensitive,double‐network hydrogel based on chitosan and an oligo(trimethylene carbonate)–poly(ethylene glycol)–oligo(trimethylene carbonate) triblock copolymer

A double‐network (DN) hydrogel was prepared through the sequential photopolymerization of oligo(trimethylene carbonate) (TPT)‐block‐poly(ethylene glycol)‐block‐oligo(trimethylene carbonate) diarylate and methacrylated chitosan (CS–MA). The swelling behavior and mechanical properties of the hydrogels were tunable via the control of the concentration of CS–MA. Under physiological conditions, the fracture stress of the DN hydrogel reached 3.4 MPa; this was more than twice that of the corresponding TPT‐block‐poly(ethylene glycol)‐block‐TPT single network (1.6 MPa). At high ionic strength, the fracture stress of the DN hydrogel reached 6.4 MPa. The DN hydrogel exhibited good cytocompatibility, as revealed by a live–dead assay. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42459.     

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     

Studies on laser-induced irreversible surface softening in a thermoset polymer of allyl diglycol carbonate (CR-39)

It is shown that controlled irreversible surface softening can be obtained in thermoset polymer of allyl diglycol carbonate (CR-39) without degrading its bulk properties on treating it with a cw-CO₂ laser. An average value of the threshold fluence for the onset of softening is found to be about 9 J/cm², which changes slightly with the interaction time and power density of the laser beam. Beyond this threshold the hardness of the treated surface decreases on increasing the power density and/or the interaction time till the onset of volatile decomposition in this polymer, which takes place at the laser fluence of 25 J/cm². Thereafter, the hardness tends to saturate at nearly 60% of its original value for the untreated surface. Formation of a new heterogenous interlinked porous microstructure has been observed in the laser softened polymer surface. Solution of the 1-dimensional heat flow equation incorporating the temperature-dependent decomposition energy of CR-39 has shown that at 9 J/cm² the surface attains the maximum temperature of about 280°C and then cools at a rate of about 10³°C/s. The starting value of the surface cooling rate increases with the fluence. A part of the absorbed energy goes in for the depolymerization, which is found to increase from about 0.004 to 4.5 J/cm² when the laser fluence is increased from 9 to 25 J/cm². The laser-induced depolymerization and subsequent rapid cooling of the surface explain the observed effects.     

Synthesis of double‐hydrophilic poly(methylacrylic acid)–poly(ethylene glycol)–poly(methylacrylic acid) triblock copolymers and their micelle formation

The aim of the work reported was to synthesize a series of double‐hydrophilic poly(methacrylic acid)‐block‐poly(ethylene glycol)‐block‐poly(methacrylic acid) (PMAA‐b‐PEG‐b‐PMAA) triblock copolymers and to study their self‐assembly behavior. These copolymeric self‐assembly systems are expected to be potential candidates for applications as carriers of hydrophilic drugs. Bromo‐terminated difunctional PEG macroinitiators were used to synthesize well‐defined triblock copolymers of poly(tert‐butyl methacrylate)‐block‐poly(ethylene glycol)‐block‐poly(tert‐butyl methacrylate) via reversible‐deactivation radical polymerization. After the removal of the tert‐butyl group by hydrolysis, double‐hydrophilic PMAA‐b‐PEG‐b‐PMAA triblock copolymers were obtained. pH‐sensitive spherical micelles with a core–corona structure were fabricated by self‐assembly of the double‐hydrophilic PMAA‐b‐PEG‐b‐PMAA triblock copolymers at lower solution pH. Transmission electron microscopy and laser light scattering studies showed the micelles were of nanometric scale with narrow size distribution. Solution pH and micelle concentration strongly influenced the hydrodynamic radius of the spherical micelles (48–310 nm). A possible reason for the formation of the micelles is proposed. Copyright © 2010 Society of Chemical Industry     

Chain extension reactions of unsaturated polyesters with bis(2‐oxazoline)s

Two different bisoxazolines, 2,2′‐(1,3‐phenylene) bis(2‐oxazoline) (1,3‐PBO) and 2,2′‐bis(2‐oxazoline) (BO) were investigated as chain extenders for short chain unsaturated polyesters (UPEs). These extenders reacted readily with carboxyl ends of unsaturated polyesters, leading to rapid molecular weight increase through coupling of oligomeric chains. Commercially available unsaturated polyesters commonly have molecular weights around 1500, usually reached after a 20‐h polyesterification reaction. When bisoxazolines were reacted with short UPE chains obtained at the 6th hour of a commercial polyesterification reaction, the molecular weight of UPE reached 1500 within 5–30 min, which provides economies and prevents the glycol loss and yellowing which are associated with extended reaction times. Styrene solubility, gel time, and thermal and mechanical properties of the chain extended polyesters remained comparable to the commercial UPE, with 8–10 min of gel time and a storage modulus about 3000 MPa. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Fluorescent microspheres of poly(ethylene glycol)–poly(lactic acid)–fluorescein copolymers synthesized by Ugi four‐component condensation

Microparticles formed by poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG) diblock copolymers containing fluorescein grafted to the polymer chain were synthesized by a Ugi four‐component condensation (UFCC) reaction. To synthesize these copolymers, lactide was first polymerized by a ring‐opening polymerization with alcohol initiators containing functional groups to give carboxyl‐ and aldehyde‐end‐functionalized PLA. Two different fluorescent block copolymers (FCPs) of PEG–PLA conjugated to fluorescein (FCP 1 and FCP 2) were then synthesized by UFCC; they gave yields in the range 65–75%. These copolymers were characterized well according their chemical structures and thermal properties, and we prepared fluorescent microspheres (FMSs) from them with the single emulsion–solvent evaporation method (FMS 1 and FMS 2). A new application of UFCC in the preparation of biomasked drug‐delivery systems is proposed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42994.     

Gellan gum–O,O′‐bis(2‐aminopropyl)‐polyethylene glycol hydrogel for controlled fertilizer release

A gellan gum–Jeffamine superabsorbent hydrogel was obtained with different crosslink densities using different amounts of (1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide hydrochloride) and N‐hydroxysuccinimide. Infrared spectroscopy and thermal analysis confirm the crosslinking. A morphology analysis indicates denser structures for samples with higher crosslinking points. The swelling degree in high‐acyl gellan gum hydrogels was equivalent to 145 times their dry weight, and 77 times when low‐acyl gellan gum was used. Hydrogels also showed a 450 min water retention, as opposed to 280 min for pure water, evidencing good humidity control, suitable for use in arid climates. They also demonstrated a maximum release of commercial fertilizer of about 400 mg per gram for KH₂PO₄ and about 300 mg per gram for NPK 20‐5‐20. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45636.     

Grafting of cotton with β‐cyclodextrin via poly(carboxylic acid)

Cyclodextrins are cyclic oligosaccharides. Cyclodextrin molecules can form inclusion complexes with a large number of organic molecules. The properties of cyclodextrins enable them to be used in a variety of different textile applications. Cyclodextrins can act as auxiliaries in washing and dyeing processes, and they can also be fixed onto different fiber surfaces. Because of the complexing abilities of cyclodextrins, textiles with new functional properties can be prepared. Poly(carboxylic acid)s such as 1,2,3,4‐butane tetracarboxylic acid (BTCA) are well‐known non‐formaldehyde crosslinking reagents. BTCA has four carboxylic acid groups, which can react with hydroxyl groups of cellulose and form stable ester bonds. We crosslinked β‐cyclodextrin molecules on hydroxyl groups of cellulose via BTCA. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1323–1328, 2005     

Bis(dipyridophenazine)(2‐(2′‐pyridyl)pyrimidine‐4‐carboxylic acid)ruthenium(II) Hexafluorophosphate: A Lesson in Stubbornness

Ruthenium complexes are currently considered to be among the most promising alternatives to platinum anticancer drugs. In this work, thirteen structural analogues and organelle/receptor‐targeting peptide bioconjugates of a cytotoxic bis(dppz)‐Ru^II complex [Ru(dppz)₂(CppH)](PF₆)₂ ( 1 ) were prepared, characterized, and assessed for their cytotoxicity and cellular localization (CppH=2‐(2′‐pyridyl)pyrimidine‐4‐carboxylic acid; dppz=dipyrido[3,2‐a:2′,3′‐c]phenazine). It was observed that structural modifications (lipophilicity, charge, and size‐based) result in the cytotoxic potency of 1 being compromised. Confocal microscopy studies revealed that unlike 1 , the screened complexes/bioconjugates do not have a preferential accumulation in mitochondria. The results of this important structure–activity relationship strongly support our initial hypothesis that accumulation in mitochondria is crucial for 1 to exert its cytotoxic action.     

Preparation and characterization of some new unsaturated polyesters based on 3,6‐bis(methoxymethyl)durene

A series of unsaturated polyester resins based on 3,6‐bis(methoxymethyl)durene with different diacids or anhydrides, namely, phthalic anhydride, maleic anhydride, and succinic acid, and different glycols, namely, 1,2‐propylene glycol, triethylene glycol, 1,4‐cyclohexane diol, and 3,6‐bis(benzyloxymethyl)durene, were prepared. Infrared and nuclear magnetic resonance spectra were used to characterize the unsaturated polyester resins obtained qualitatively and quantitatively. The average‐number molecular weight (M^?_n) was determined by end‐group analysis. These polyesters were found to cure with styrene at room temperature. The thermal behavior of the styrenated polyesters was studied via thermogravimetrical analysis and differential scanning calorimetry (TGA and DSC). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3388–3398, 2001     

Catalyst free synthesis of poly(l‐lactic acid)–poly(propylene glycol) multiblock copolymers and their properties

A simple, green, and economical method for the synthesis of poly(l ‐lactic acid)–poly(propylene glycol) (PLLA–PPG) copolymers is put forward and a series of multiblock PLLA–PPG are synthesized with 1,6‐hexamethylene diisocyanate as chain extender of the melt polymerization. The effect of PPG content on the properties of PLLA–PPG copolymers is also investigated. The elongation at break of the resulting copolymer film with only 5% weight content PPG is 280%, and the tensile strength is 20 MPa. Dynamic mechanical analysis results demonstrated the existence of the shape memory effect for all the copolymers films and the shape recovery ratio of 101% is achieved for PLLA–PPG copolymer film with 5% weight PPG. The process for the synthesis of PLLA–PPG copolymers in the total absence of potentially toxic solvents and catalysts is analyzed, and the films of PLLA–PPG exhibit toughness and shape memory effect. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45299.     

Electrochemical deposition of poly[N,N′‐ethylene–bis(salicylideneiminato)–nickel(II)] nanobelts as electrode materials for supercapacitors

N,N′‐ethylene–bis(salicylideneiminato)]–nickel(II) [Ni(salen)] was synthesized in situ onto the surface of multiwalled carbon nanotubes via a one‐step potentiostatic electrodeposition as one‐dimensional nanobelts. The synthetic process was free of any templates or additives. Potential played a key role in the formation of the poly[N,N′‐ethylene–bis(salicylideneiminato)]–nickel(II)] {poly[Ni(salen)]} nanobelts, and the electrical conductivities of the poly[Ni(salen)] decreased with increasing deposition time. The capacitance values of poly[Ni(salen)] were 272, 195, and 146 F/g at 0.05 mA/cm² for deposition times of 10, 20, and 30 min, respectively. The capacitance of the sample with a particle structure was much lower than that of poly[Ni(salen)] with a nanobelt structure. The poly[Ni(salen)] nanobelts exhibited a better capacitive behavior than the poly[Ni(salen)] particles because the nanobelt structure made access for the charge and ion to the inner part of the electrode easier. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39561.     

Effect of phosphotungstic acid blending on properties of sulfonated poly(ether ether ketone)–poly(ethylene glycol) crosslinked membranes

This study shows the effect of phosphotungstic acid (PWA) blended into a sulfonated poly(ether ether ketone) (SPEEK) and poly(ethylene glycol) (PEG) crosslinked membrane on the membrane's electrochemical and mechanical properties. The PWA weight percentage was varied from 0 to 50%. All of the membranes were equilibrated with water at room temperature (27 °C) and elevated temperature (60 °C), and their properties were investigated. A scanning electron microscope with energy dispersive X‐ray was used to ascertain the tungsten concentration remaining in the membrane after water treatment. A systematic decrease in tungsten concentration was seen with the increase in the initial PWA percentage. The membrane blended with 10% PWA showed the best properties, having the highest conductivity (0.11 S cm^?1), mechanical strength, and chemical stability. Membranes with 10% PWA and without PWA were studied in a H₂/O₂ fuel cell. The membrane blended with 10% PWA gave 33% more power density than the membrane without PWA. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46667.     

Synthesis and thermal properties of poly(acrylonitrile‐co‐allyl glycidyl ether)‐graft‐methoxypoly(ethylene glycol) copolymers as novel solid–solid phase‐change materials for thermal energy storage

We synthesized a series of poly(acrylonitrile‐co‐allyl glycidyl ether)‐graft‐methoxypoly(ethylene glycol) (PAA‐g‐MPEG) copolymers as novel polymeric solid–solid phase‐change materials by grafting methoxypoly(ethylene glycol) (MPEG) to the main chain of poly(acrylonitrile‐co‐allyl glycidyl ether) (PAA). PAA was the skeleton, and MPEG was a functional side chain, which stored and released heat during its phase‐transition process. Fourier transform infrared spectroscopy and ¹H‐NMR spectroscopy analysis were performed to investigate the chemical structures. The crystalline morphology and crystal structures were also measured with polarized optical microscopy and X‐ray diffraction. Moreover, the thermal‐energy‐storage properties, thermal stability, and thermal reliability of the PAA‐g‐MPEG copolymers were characterized by differential scanning calorimetry and thermogravimetric analysis (TGA) methods. These analysis results indicate that the MPEG chains were successfully grafted onto PAA, and we found that the PAA‐g‐MPEG copolymers had typical solid–solid phase‐transition temperatures in the range 11–54 °C and high latent heat enthalpies between 44 and 85 J/g. In addition, the as‐prepared PAA‐g‐MPEG copolymers showed reusability and thermal reliability, as shown by the thermal cycle testing and TGA curves. Therefore, the synthesized PAA‐g‐MPEG copolymers have considerable potential for thermal energy storage. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46641.