Hydrogen bond lifetimes and statistics of aqueous mono‐, di‐ and tri‐ethylene glycol

Hydrogen bond statistics, energy distributions of hydrogen bonds and hydrogen bond lifetimes for aqueous monoethylene glycol (MEG), diethylene glycol (DEG), and triethylene glycol (TEG) were investigated at temperatures ranging from 275 to 370 K at 101.325 kPa using molecular dynamics simulations. Each individual type of hydrogen bond were studied separately to better understand how each type of hydrogen bond affected the collective behavior often measured in experiments. We also studied the effects of glycols on water–water hydrogen bond structures and lifetimes. Decay constants for hydroxyl type hydrogen bonds, as well as for water based hydrogen bonds were in the same order, thus indicating that all these hydrogen bonds play an essential role in the process of dielectric relaxation. Correlations between water hydrogen bond distances and angles were not affected markedly by adding glycols. However, hydrogen bond lifetimes increased by 9, 29, and 62 times by adding MEG, DEG, and TEG, respectively. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1674–1689, 2017     

A quality relevant non‐Gaussian latent subspace projection method for chemical process monitoring and fault detection

Partial least‐squares (PLS) method has been widely used in multivariate statistical process monitoring field. The goal of traditional PLS is to find the multidimensional directions in the measurement‐variable and quality‐variable spaces that have the maximum covariances. Therefore, PLS method relies on the second‐order statistics of covariance only but does not takes into account the higher‐order statistics that may involve certain key features of non‐Gaussian processes. Moreover, the derivations of control limits for T² and squared prediction error (SPE) indices in PLS‐based monitoring method are based on the assumption that the process data follow a multivariate Gaussian distribution approximately. Meanwhile, independent component analysis (ICA) approach has recently been developed for process monitoring, where the goal is to find the independent components (ICs) that are assumed to be non‐Gaussian and mutually independent by means of maximizing the high‐order statistics such as negentropy instead of the second‐order statistics including variance and covariance. Nevertheless, the IC directions do not take into account the contributions from quality variables and, thus, ICA may not work well for process monitoring in the situations when the quality variables have strong influence on process operations. To capture the non‐Gaussian relationships between process measurement and quality variables, a novel projection‐based monitoring method termed as quality relevant non‐Gaussian latent subspace projection (QNGLSP) approach is proposed in this article. This new technique searches for the feature directions within the measurement‐variable and quality‐variable spaces concurrently so that the two sets of feature directions or subspaces have the maximized multidimensional mutual information. Further, the new monitoring indices including I² and SPE statistics are developed for quality relevant fault detection of non‐Gaussian processes. The proposed QNGLSP approach is applied to the Tennessee Eastman Chemical process and the process monitoring results of the present method are demonstrated to be superior to those of the PLS‐based monitoring method. © 2013 American Institute of Chemical Engineers AIChE J 60: 485–499, 2014     

A Bayesian framework for real‐time identification of locally weighted partial least squares

Just‐in‐time (JIT) learning methods are widely used in dealing with nonlinear and multimode behavior of industrial processes. The locally weighted partial least squares (LW‐PLS) method is among the most commonly used JIT methods. The performance of LW‐PLS model depends on parameters of the similarity function as well as the structure and parameters of the local PLS model. However, the regular LW‐PLS algorithm assumes that the parameters of the similarity function and structure of the local PLS model are known and do not fully utilize available knowledge to estimate the model parameters. A Bayesian framework is proposed to provide a systematic way for real‐time parameterization of the similarity function, selection of the local PLS model structure, and estimation of the corresponding model parameters. By applying the Bayes' theorem, the proposed framework incorporates the prior knowledge into the identification process and takes into account the different contribution of measurement noises. Furthermore, Bayesian model structure selection can automatically deal with the model complexity problem to avoid the overfitting issue. The advantages of this new approach are highlighted through two case studies based on the real‐world near infrared data. © 2014 American Institute of Chemical Engineers AIChE J, 61: 518–529, 2015     

Simple,convenient, low‐cost,and solventless greener way to pH‐responsive polymeric hydrogels: Synthesis and characterization

Utilization of hydrogels in a simple, low‐cost, solventless. and greener approach toward the pH‐responsive hydrogels which comprise of citric acid (CA) with varying glycol unit viz., ethylene glycol (EG), diethylene glycol (DEG), and triethylene glycol (TEG) were prepared along with methacrylic acid (MAA). The formations of pre‐polymer and hydrogels were confirmed using ¹³C‐NMR and FT‐IR spectral techniques. Thermal studies (TGA, DTA, and DSC) and morphology (SEM) of various hydrogels have been investigated. Swelling studies of hydrogels at different pH ranging from 4.0 to 10.0 have also been performed. The results of swelling studies imply that the percentage of swelling is comparatively higher at neutral pH than acidic and alkaline pH. The reciprocal relationship was identified among thermal stability and swelling behavior of hydrogels while increasing the chain length from EG to TEG. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41921.     

Synthesis and properties of polyurethane‐urea‐based liquid bandage materials

To obtain ideal liquid bandage polymer materials, a series of polyurethane‐urea dispersions were synthesized from 4,4′‐diisocyanato dicyclohexylmethane (H₁₂MDI) and ethylene diamine with different molar ratio of polyol blend [polyethylene glycol (PEG, M_n = 2000 g/mol)/hydroxy terminated poly(dimethylsiloxane) (PDMS, M_n = ～ 550 g/mol)] and acetone/ethanol as a solvent. The effect of PDMS content in PEG/PDMS on the viscosity, mechanical properties, water contact angle/surface energy, insolubility in water (%), water absorption (%), equilibrium water content (%), and water vapor transmission rate (g m^?2 day^?1) of polyurethane‐urea films was investigated. As PDMS content increased, the water contact angle, insolubility in water, and tensile strength/elastic recovery of film sample increased; however, the surface energy, water absorption (%), equilibrium water content (%), and water vapor transmission rate (g m^?2 day^?1) of film sample decreased. By a wound‐healing evaluation using a full‐thickness rat model experiment, it was found that a wound covered with a typical polyurethane‐urea liquid bandage film (PD2 sample) was filled with new epithelium without any significant adverse reactions. These results suggest that the polyurethane‐urea‐based liquid bandages (samples: PD2 and PD3) prepared in this study may have high potential as new wound dressing materials, which provide and maintain the adequate wet environment required to prevent scab formation and dehydration of the wound bed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Novel surface modification of cellulose film by heat‐set finishing method using poly(ethylene glycol)‐coated polystyrene nanospheres

The nanosphere having hydrophobic backbone and hydrophilic branches was used as the agent for the surface modification of a cellulose film. They were obtained by dispersion copolymerization of styrene (St) and poly(ethylene glycol) (PEG) macromonomers in an ethanol/water solution at 60°C by using a free‐radical initiator. The PEG‐coated polystyrene (PSt) nanosphere–water dispersions were prepared at concentrations of 0.1, 0.2, 0.5, and 1.0% (w/v). A measure of 1 mL of the dispersion was poured over the cellulose film, cut into a strip of 5 × 5 cm². The film was pressed by plates heated at 200°C with 6.8 g/cm² pressure for 2 min to melt PSt nanospheres and fix them on the cellulose film. The morphology of the film surface was also observed by a scanning electron microscopy (SEM). The resulting modified surface was characterized by X‐ray photoelectron spectroscopy (XPS). The contact angle, the moisture absorption, and the leakage of electrostatic charge from the film were studied. The surface of the film treated with the dispersion had high water‐repellency, although the bulk properties did not change. It was found that the dispersion was effective in making the cellulose surface hydrophobic. The surface modification of cellulose film was successful by using this simple method. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1516–1523, 1999     

Sorption and desorption parameters of water or ethanol in light‐cured dental dimethacrylate resins

Two cycles of sorption/desorption of water or ethanol by light‐cured dental resins of bisphenol A glycol dimethacrylate (Bis‐GMA), bisphenol A ethoxylated dimethacrylate (Bis‐EMA) urethane dimethacrylate (UDMA) triethylene glycol dimethacrylate and decanediol dimethacrylate (D₃MA) were studied. The experimental curves m_t = f(t) taken for the first water sorption by poly‐Bis‐GMA, poly‐Bis‐EMA and poly‐UDMA showed a maximum. A maximum was also observed in the curve obtained for first sorption of ethanol by poly‐Bis‐GMA. In all other cases, the curves for sorption or desorption of water or ethanol showed Fickian behavior. The experimental data obtained for first sorption of water or ethanol were perfectly fitted to a new proposed equation, which predicts water or ethanol sorption with simultaneous extraction of unreacted the monomer. This equation gave us the possibility for the determination of the diffusion coefficient of the extraction of the unreacted Bis‐GMA during the water and ethanol sorption, as well as the diffusion coefficient of the extraction of the unreacted Bis‐EMA and UDMA during the water sorption. The maximum water or ethanol absorbed at equilibrium and the diffusion coefficient are determined from the second sorption/desorption cycle during which the extraction of the monomer is negligible. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Structural features of poly(alkylene ether carbonate) diols and intermediates formed during their preparation

Capillary vapor-phase chromatography and carbon-13 nuclear magnetic resonance (NMR) have been used to elucidate the structure of poly(ethylene ether carbonate) diols and certain intermediates produced by the oligomerization of ethylene carbonate (EC) using monoethylene glycol (MEG) or diethylene glycol (DEG) as initiator and catalyzed by sodium stannate trihydrate. These diols are alternating copolymers of carbon dioxide and DEG which also contain smaller amounts of higher glycols as determined by comparing their ¹³C NMR spectra to the spectra of model compounds. Diethylene glycol is an important reaction intermediate and is present in steady-state concentrations. Although both 2-hydroxyethyl carbonate and 2-hydroxyethyl ether end groups are present at an intermediate stage in the reaction, only 2-hydroxyethyl ether end groups are present at high EC conversion. Molecular weight builds as a smooth function of conversion and time.     

Adsorption properties of novel chelating resins containing 2‐amino‐5‐methylthio‐1,3,4‐thiadizole and hydrophilic spacer arms for Hg2+ and Ag+

The adsorption properties, including the adsorption kinetics, adsorption isotherms, and adsorption selectivity, of newly formed chelating resins that contained a heterocyclic functional group and a hydrophilic spacer arm of poly(ethylene glycol) [polystyrene–diethylene glycol–2‐amino‐5‐methylthio‐1,3,4‐thiadizole (PS–DEG–AMTZ) and polystyrene–triethylene glycol–2‐amino‐5‐methylthio‐1,3,4‐thiadizole (PS–TEG–AMTZ)] were studied in detail. The results show that the adsorption kinetics of PS–DEG–AMTZ and PS–TEG–AMTZ for Hg²⁺ and Ag⁺ could be described by a pseudo‐second‐order rate equation. The introduction of a spacer arm between the polymeric matrix and functional group was beneficial for increasing the adsorption rates. The apparent activation energies of the resins for Hg²⁺ and Ag⁺ were within 20.89–32.32 kJ/mol. The Langmuir model could describe the isothermal process of Hg²⁺ and Ag⁺. The competitive adsorption of the resins for Hg²⁺ and Ag⁺ in binary mixture systems was also investigated. The results show that Hg²⁺ and Ag⁺ were adsorbed before the other metal ions, such as Cu²⁺, Zn²⁺, Fe³⁺, Cd²⁺, and Pb²⁺, under competitive conditions. Five adsorption–desorption cycles were conducted for the reuse of the resins. The results indicate that these two resins were suitable for reuse without considerable changes in the adsorption capacity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of dialcohols on properties of poly(ethylene 2,6‐naphthalate) copolymers

Properties of poly(ethylene 2,6‐naphthalate) (PEN) and its copolymers containing diethylene glycol (DEG), propanediol (PD), butanediol (BD), and bisphenol A ethoxylate (BSA) were investigated. The copolymer composition was determined by ¹H‐NMR spectroscopy. It has a higher value than the feed composition due to the high volatility of ethylene glycol (EG). The melting temperature of the copolymers was gradually depressed with the increase of dialcohol in the composition. The complex viscosity of the copolymers did not depend on the molecular weight, but on the chemical structure. The complex viscosity of the copolymers containing 3 mol % of DEG, BD, and 5 mol % of BD was lower than that of PEN, and the mechanical properties were similar with the value of PEN. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2900–2905, 1999     

Ethanol perm‐selective B‐ZSM‐5 zeolite membranes from dilute solutions

Boron‐substituted MFI (B‐ZSM‐5) zeolite membranes with high pervaporation (PV) performance were prepared onto seeded inexpensive macroporous α‐Al₂O₃ supports from dilute solution and explored for the separation of ethanol/water mixtures by PV. The effects of several parameters on microstructures and PV performance of the B‐ZSM‐5 membranes were examined systematically, including the seed size, synthesis temperature, crystallization time, B/Si ratio, H₂O/SiO₂ ratio and silica source. A continuous and compact B‐ZSM‐5 membrane was fabricated from solution containing 1 tetraethyl orthosilicate/0.2 tetrapropylammonium hydroxide/0.06 boric acid/600 H₂O at 448 K for 24 h, showing a separation factor of 55 and a flux of 2.6 kg/m² h along with high reproducibility for a 5 wt % ethanol/water mixture at 333 K. It was demonstrated that the incorporation of boron into mobile five (MFI) structure could increase the hydrophobicity of B‐ZSM‐5 membrane evidenced by the improved contact angle and amount of the adsorbed ethanol, and thus enhance the PV property for ethanol/water mixtures. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2447–2458, 2016     

Hygrothermal aging of rubber‐modified and mineral‐filled dicyandiamide‐cured DGEBA epoxy resin. III. Dielectric spectroscopy investigation

The effects of moisture absorption on the dielectric properties of a rubber‐modified, mineral‐filled, epoxy resin based on the diglycidyl ether of bisphenol A cured with dicyandiamide are reported. Samples of the resin were aged by immersing in deionized water, or 5% w/w NaCl solution, at elevated temperatures. Dielectric measurements were carried out over the frequency range 10^?1 to 6 × 10⁵ Hz. A featureless dielectric spectrum was observed with both real and imaginary dielectric permittivity increasing with the amount of absorbed water. The change in the dielectric properties with absorption of water was independent of presence of salt, temperature of exposure, and aging history, although a hysteresis of the hydration–dehydration process was observed at low frequencies. Two types of absorbed water were observed—water molecularly dispersed within the epoxy matrix and clustered water in spherical microcavities. The time dependence of the real dielectric permittivity measured at 10 kHz was found to closely resemble that of the water absorption, which allowed the activation energy of diffusion to be calculated from both dielectric and gravimetric data. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1011–1024, 2002; DOI 10.1002/app.10368     

Stimuli‐responsive molecularly imprinted hybrid polymer gel as a potential system for controlled release

The purpose of this study is to develop a stimuli‐responsive hybrid polymer gel system with an improved mechanical stability as a controlled drug delivery carrier that can undergo phase transition by the stimulation of ethanol–water mixture. For this aim, trimethoxysilane terminated poly(propylene glycol) by coupling of 3‐isocyanatopropyl‐triethoxysilane with the hydroxyl end groups of poly(propylene glycol) through urethane bonds was synthesized. Hybrid polymer gels prepared in the presence of tryptophan (Trp), as a model of drug, were characterized and gelation time of polymer network was obtained by monitoring the fluorescence emission of Trp in pre‐gel solution. Swelling, solvent uptake and release kinetic of polymer gels were evaluated depending on time. The diffusional exponents (n) and diffusion constants (k) of each gel were calculated by using the swelling kinetic data. The effect of precursors as a monomer on Trp release profile was analyzed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42913.     

Synthesis and properties of the copolymer of acrylamide with 2‐acrylamido‐2‐methylpropanesulfonic acid

A cross‐linked copolymer of acrylamide (AM) with 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS) was prepared by solution polymerization. In this reaction, potassium persulfate (PPS) and N,N′‐methylenebisacrylamide (NMBA) were used as initiator and cross‐linker, respectively. This copolymer, poly(acrylamide‐co‐2‐acrylamido‐2‐methylpropanesulfonic acid) (PAMA), can absorb up to 1749 g/g of dry polymer in distilled water and 87 g/g of dry polymer in 0.9 wt % NaCl aqueous solution at room temperature. The PAMA also has excellent performance in absorbing pure alcohols. Its absorbencies in methanol and glycol are about 310 g/g and 660 g/g, respectively. The effects of various salt solutions on the swelling properties were studied systematically, and the relationship between the absorbency and the concentrations of the different salt solutions can be expressed as Q = kcⁿ. Experimental results indicate that the absorbencies were stable at different water temperatures. The swelling rates of the copolymer in distilled water and a water/ethanol mixture (V_water:V_alcohol = 1:1) were also investigated, and the results showed that PAMA could absorb 992 g of distilled water per gram of dry polymer and 739 g of water/ethanol mixture per gram of dry polymer in five minutes. The PAMA has such good water retention at higher temperatures that the swollen gel can retain 71.6 and 49.5% of the maximum absorbency after being heated for 9 hours at 60 and 80 °C, respectively. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3481–3487, 2003     

Effect of glycols on the properties of polyester polyols and of room‐temperature‐curable casting polyurethanes

A series of liquid polyester polyols (PEs) from adipic acid (AA), phthalic anhydride (PA) and trihydroxymethylpropane (TMP), and such glycols as ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), butanediol (BD) and hexanediol (HD), were prepared. Polyurethanes (PUs) were obtained from the PEs and polyaryl polymethylene isocyanate (PAPI) at room temperature. The effects of the structures of the glycols on viscosity, glass transition temperature and crystallinity of the PEs, and the mechanical, thermal and boiling‐water‐resistant properties of PUs were studied. The experiments showed that the viscosities and glass transition temperatures of the PEs decreased as the length of the glycol chains increased. The polyester based on HD lost flowability because of crystallization. The tensile strength and hardness of the PUs obtained decreased with increasing the length of the glycol chains, while the resistance to thermal deformation and boiling water increased. Thermogravimetric analysis demonstrated that thermal degradation of the polyurethane based on DEG proceeded in one step and for the others in two steps. The initial degradation temperature of the polyurethane based on EG was the lowest and that of the polyurethane based on BD was the highest. The residue of the former at 450 °C was the greatest, while that of the latter was the lowest. Copyright © 2004 Society of Chemical Industry     

A practical parametrical characterization of the Fenton and the photo‐Fenton sulfamethazine treatment using semi‐empirical modeling

BACKGROUND: Sulfamethazine (SMT) has received little attention in the water treatment literature. Yet, SMT is among the non‐biodegradable substances increasingly found in aqueous media and affecting both public health and wastewater treatments. For a long time, advanced oxidation processes (AOPs) were studied via pure empirical modeling, although the surface response models resulting from lumped information (TOC, COD, etc.) present limitations regarding extrapolation and optimization. Conversely, detailed first‐principles modeling may not be affordable due to the computational burden and the chemical analysis needs. Thus, a balanced approach may be practical in many cases. RESULTS: Experiments on SMT solutions (500 mL, 50 mg L^?1) were performed under conditions set by an experimental design. A set of replicated degradation time‐profiles (TOC and SMT concentrations) was obtained and a semi‐empirical kinetic model was fitted to these data to determine maximum conversion and kinetic rate. CONCLUSIONS: SMT can be completely degraded from water via photo‐Fenton treatment. Conditions for this treatment were investigated and its outcomes were systematically characterized by a simple kinetic model and two lumped parameters, conversion and kinetic rate. Both, the model and the corresponding parametrical characterization are introduced as a means to discriminate the most efficient treatment conditions in a practical and efficient way. Copyright © 2011 Society of Chemical Industry     

Membrane Design for Direct Ethanol Fuel Cells: A Hybrid Proton‐Conducting Interpenetrating Polymer Network

A series of hybrid proton‐conducting membranes with an interpenetrating polymer network (IPN) structure was designed with the direct ethanol fuel cell (DEFC) application in mind. In these membranes, glutaraldehyde crosslinked poly(vinyl alcohol) (PVA) were interpenetrated with the copolymer of 2‐acrylamido‐2‐methyl‐propanesulphonic acid (AMPS) and 2‐hydroxyethyl methacrylate (HEMA) crosslinked by poly(ethylene glycol) dimethacrylate (PEGDMA). Silica from the in situ sol–gel hydrolysis of tetraethyl orthosilicate (TEOS) was uniformly dispersed in the polymer matrix. The membranes fabricated as such had ion exchange capacities of 0.84–1.43 meq g^–1 and proton conductivities of 0.02–0.11 S cm^–1. The membranes exhibited significantly lower fuel permeabilities than that of Nafion. In a manner totally unlike Nafion, fuel permeabilities were lower at higher fuel concentrations, and were lower in ethanol than methanol solutions. These behaviours are all relatable to the unique swelling characteristics of PVA (no swelling in ethanol, partial swelling in methanol and extensive swelling in water) and to the fuel blocking and swelling suppression properties of silica particles. The membranes are promising for DEFC applications since a high concentration of fuel may be used to reduce fuel crossover and to improve the anode kinetics for a resultant increase in both the energy and power densities of the fuel cell.     

Analysis of roll wave characteristics under low liquid loading two‐phase flow conditions

An experimental study is conducted using a 0.152‐m ID facility to investigate the wave characteristics of two‐phase stratified wavy flow in horizontal pipelines. The experiments are conducted under low liquid loading condition, which is very commonly observed in wet gas pipelines. The experiments are conducted with water as the liquid phase, and repeated with 51 wt % of monoethylene glycol (MEG) in the aqueous phase to analyze the effects of MEG presence on wave characteristics. The experimental range of this study covers superficial gas velocity, v_Sg, values of 9–23 m/s and superficial liquid velocity, v_SL, values of 0.01–0.02 m/s. Similar test matrices are completed for the cases with and without MEG in the aqueous phase. A conductivity probe system is used to measure the wave characteristics at the liquid–gas interface. These characteristics include the wave celerity, frequency, amplitude, length, and liquid film thickness. The experimental oil–air wave characteristics data of Gawas et al. (Int J Multiphase Flow. 2014;63:93–104) is also used for comparison purposes. The trends in the resulting wave characteristics with respect to input parameters are investigated, for oil, water, or MEG–water mixture as the liquid phase. Common predictive methods for interfacial wave celerity, including shallow water theory, Watson (Proceedings of the 4th International Conference in Multi‐Phase Flows, Nice, France. 1989:495–512), Paras et al. (Int J Multiphase Flow. 1994;20(5):939–956), Al‐Sarkhi et al. (AIChE J. 2012;58(4):1018–1029), and Gawas et al. (Int J Multiphase Flow. 2014;63:93–104) are evaluated in comparison with the experimental data. The results of the wave frequency correlation of Al‐Sarkhi et al. (AIChE J. 2012;58(4):1018–1029) are also compared with the experimental wave frequency data. Lastly, a correlation is developed to predict the relative wave amplitude, as a function of superficial gas Weber number and liquid velocity number. Most of the commonly used two‐phase stratified flow models are developed with the assumption of steady‐state conditions, and neglect the transient wave effects. This study provides valuable experimental results on wave characteristics of stratified wavy flow for different types of liquid phase. Moreover, a comprehensive analysis of the parameters affecting the wave characteristics of stratified wavy flow is presented. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3177–3186, 2017     

Synthesis,characterization, and hydrolytic degradation of biodegradable poly(ether ester)‐urethane copolymers based on ε‐caprolactone and poly(ethylene glycol)

In this article, a new kind of biodegradable poly(ε‐caprolactone)‐poly(ethylene glycol)‐poly(ε‐caprolactone)‐based polyurethane (PCEC‐U) copolymers were successfully synthesized by melt‐polycondensation method from ε‐caprolactone (ε‐CL), poly(ethylene glycol) (PEG), 1,4‐butanediol (BD), and isophorone diisocyanate (IPDI). The obtained copolymers were characterized by ¹H‐nuclear magnetic resonance (¹H‐NMR), FTIR, and gel permeation chromatography (GPC). Thermal properties of PCEC‐U copolymers were studied by DSC and TGA/DTG under nitrogen atmosphere. Water absorption and hydrolytic degradation behavior of these copolymers were also investigated. Hydrolytic degradation behavior was studied by weight loss method. ¹H‐NMR and GPC were also used to characterize the hydrolytic degradation behavior of PCEC‐U copolymers. The molecular weight of PCL block and PEG block in soft segment and the content of hard segment strongly affected the water absorption and hydrolytic degradation behavior of PCEC‐U copolymers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and characterization of an amphiphilic macrophotoinitiator based on 2‐hydroxyl‐2‐methyl‐1‐phenylpropanone

On the basis of 2‐hydroxyl‐2‐methyl‐1‐phenylpropanone (HMPP) and poly(ethylene glycol) (PEG), we prepared amphiphilic macrophotoinitiators (HMPP–PEG–HMPP) by first reacting HMPP with isophorone diisocyanate and subsequently reacting it with PEGs with different chain lengths. Fourier transform infrared spectroscopy, high‐performance liquid chromatography, and ¹H‐NMR were used to confirm the structure of the amphiphilic macrophotoinitiators. Ultraviolet (UV) absorption spectra showed that the amphiphilic macrophotoinitiators had maximum absorption wavelengths that were similar to those of the low‐molecular‐weight photoinitiator HMPP. The photolysis rate of the amphiphilic macrophotoinitiators was slightly lower than that of HMPP, but the migration rate of the amphiphilic macrophotoinitiators from a UV‐cured matrix was much lower compared to that of HMPP. Because of their amphiphilic nature, these macrophotoinitiators may play roles as both photoinitiators and emulsifiers, and they have been applied to the solution polymerization of water‐soluble monomer acrylamide in water and the emulsion polymerization of methyl methacrylate. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43910.