Removal of methylene blue (aq) using untreated and acid‐treated eucalyptus leaves and GA‐ANN modelling

In the present batch study, eucalyptus leaves (EUL), H₂SO₄‐treated eucalyptus leaves (SEUL), and H₃PO₄‐treated eucalyptus leaves (PEUL) are used as bio‐adsorbents for the removal of methylene blue (MB). The bio‐adsorption is executed to inspect the results of the variation between different experimental variables such as pH (2–10), adsorbent dose (1–10 g/L), contact time (5–360 min), and temperature (298–318 K) on the bio‐adsorption of MB. The Langmuir isotherm (R² = 0.99) fitted adequately to the bio‐adsorption data for the initial MB concentrations of 10–300 mg/L. It is also necessary to mention that the MB bio‐adsorption occurred in the order of a monolayer on the EUL, SEUL, and PEUL. The bio‐adsorption kinetics have been fitted by the pseudo‐second‐order model (R² ≥ 0.99) for various MB concentrations. The maximum bio‐adsorption capacity was 194.34 mg/g and was achieved for the H₃PO₄‐treated eucalyptus leaves (PEUL). These results showed that EUL, SEUL, and PEUL may be utilized as a favourable low‐cost bio‐adsorbent to eliminate MB from aqueous solutions. With safe disposal methods in mind, this investigation has revealed the eco‐friendliness of the bio‐adsorbents. A prediction of the removal percentage of methylene blue using a genetic algorithm (GA) from the data collected from the experiment has also been tested. The results related to the prediction using the GA‐ANN are accurate.     

Physicochemical and adsorptive properties of fast‐pyrolysis bio‐chars and their steam activated counterparts

BACKGROUND: This study investigated steam‐activation as a technology for adding value to fast‐pyrolysis bio‐chars. Due to short residence times in the fluidized‐bed pyrolyzer, required to maximize bio‐oil production, the bio‐char structure tends to be underdeveloped thereby impacting its full potential application as a value‐added co‐product. RESULTS: The bio‐chars of several substrates from a fluidized‐bed fast pyrolyzer and their respective corresponding steam‐activated counterparts were characterized for their surface areas and metal ion adsorption (copper, cadmium, nickel and zinc). Surface areas increased with activation from negligible to 136–793 m² g^?1 of material, with concomitant pore development evidenced by scanning electron microscopy and mathematical modeling. Affinity to Cu²⁺ was highest with adsorption efficiencies for 1 mmol L^?1 solutions ranging from 60–85%. Metal ion adsorption performance was feedstock dependent and increased with activation, possibly due to improved access to highly reactive adsorption sites associated with the inorganic material in the feedstock. CONCLUSION: Because of their higher yields and metal ion uptake, broiler litter and alfalfa stems could be the feedstock of choice when considering upgrading fast pyrolysis bio‐char for metal ion uptake. However, if the development of large surface areas is required, guayule bagasse and soybean straw could be the preferred feedstock. Published 2010 by John Wiley and Sons, Ltd.     

Surface‐initiated nitroxide‐mediated radical polymerization of 4‐vinylpyridine on magnetite nanoparticles

Poly (4‐vinylpyridine) (P4VP) brushes had been prepared by the surface‐initiated nitroxide‐mediated radical polymerization of 4‐VP on the surface of 3‐methacryloxyproyltrimethoxysilane (3‐MPS)‐modified magnetite nanoparticles with an average diameter of 30 nm. The grafting polymerization was accomplished by nitroxide‐mediated polymerization of 4‐VP, using 4‐hydroxyl‐2,2,6,6‐tetramethyl‐1‐piperidinyl‐oxy (HTEMPO·) free radical as capping agent and benzoyl peroxide (BPO) as initiator. X‐ray photoelectron spectra (XPS) measurement demonstrated that the alkoxysilane initiator layer had formed on the magnetite surface. Gel permeation chromatograph analysis and XPS measurement suggested that the amount of grafted P4VP increases with increasing grafting time. The amount of P4VP grafted on the surface could be determined to be 0.09 chains/nm² by thermogravimetric analysis. The P4VP‐grafted magnetite particles exhibited the characteristics of multidomain system, distinct from the single domain attributes of the pure magnetite particles. Atomic force‐microscopy analysis revealed the diameter of the grafted P4VP magnetic latex particles is in the range of 120 nm to 150 nm. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Characterisation of the mixture product of ether‐soluble fraction of bio‐oil (ES) and bio‐diesel

A method of upgrading the properties of bio‐oil with bio‐diesel has been taken in this article. Firstly, the unpopular pyrolytic lignin fraction is extracted from bio‐oil using ether, the rest ether‐soluble fraction of bio‐oil, named ES is mixed with bio‐diesel according to emulsification. The optimal conditions for obtaining a stable ES/bio‐diesel mixture are with octanol surfactant dosage of 3% by volume; initial ES to bio‐diesel ratio of 4:6 by volume; stirring intensity of 1200 rpm; mixing time of 15 min and mixing temperature at 30°C. Additionally, selected fuel properties such as viscosity, water content and acid number are measured for characterising the ES/bio‐diesel mixture. Thermogravimetric analysis (TGA) has been used to further evaluate the thermal properties. Data from the TGA and Fourier transform infrared spectroscopy (FTIR) analyses confirm the presence or absence of certain group of chemical compounds in the mixture. Proton and carbon atoms assignments are further confirmed by ¹H NMR (nuclear magnetic resonance) and ¹³C NMR analysis, respectively. © 2011 Canadian Society for Chemical Engineering     

Thermal stability of poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate)/modified montmorillonite bio‐nanocomposites

Poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) (P34HB)/modified montmorillonite (EMMT) bio‐nanocomposites were prepared via melt intercalation method. The thermal stability of the bio‐nanocomposites was investigated. The results showed that the decomposition temperature (T _5%) of P34HB/EMMT bio‐nanocomposite reached 271.4°C, 39.9°C higher than that of pure P34HB. The remarkable thermal stability enhancement was presumably originated from the uniform dispersion of EMMT in the matrix and intercalated structures of P34HB/EMMT bio‐nanocomposites, which was related to the increased compatibility of EMMT and P34HB caused by the ester group in EMMT. TGA‐FTIR analysis on the thermal degradation procedures of the bio‐nanocomposites manifested that the introduction of EMMT did not alter the degradation mechanism of P34HB. However, the intercalated structures hindered the mobility of P34HB macromolecular and slowed down the decomposing process of P34HB. POLYM. COMPOS., 38:673–681, 2017. © 2015 Society of Plastics Engineers     

Bio‐inspired layer‐by‐layer assembled hybrid films for improvement of mechanical properties

Inspired by many strong, toughness, and stiffness materials in nature, we first present bio‐inspired structure hybrid films fabricated by layer‐by‐layer assembly technique based on low‐surface‐energy graphite micro‐sheets and styrenic block copolymers. Compared with pure polymer films, the mechanical properties of the hybrid films have been greatly modified in failure stress, elastic modulus, and failure energy due to the rigid bio‐inspired structure. After graphite micro‐sheets surface modified by dopamine, a better enhancement in mechanical properties was achieved with the assistance of dopamine surface modification in the almost same content of inorganic component. The layer‐by‐layer assembly method was improved by introducing the wet‐coating techniques that has been widely applied in industry. This improved method is more easily to fabricate large‐area hybrid films without destroying the bio‐inspired structure of the hybrid films. This improved method and bio‐inspired structure were first applied to reinforce elastomer in this work, while this bio‐inspired structure has shown great success when applied in the area of plastic. POLYM. COMPOS. 34:1261–1268, 2013. © 2013 Society of Plastics Engineers     

Effect of sparse long‐chain branching on the step‐strain behavior of a series of well‐defined polyethylenes

The effect of sparse long chain branching, LCB, on the shear step‐strain relaxation modulus is analyzed using a series of eight high‐density polyethylene (HDPE) resins. Strains of 1 to 1250% are imposed on materials with LCB content ranging from zero to 3.33 LCB per 10,000 carbon atoms. All materials are observed to obey time–strain separation beyond some characteristic time, τ_k. The presence of LCB is observed to increase the value of τ_k relative to the linear resin. The behavior of the relaxation modulus at times shorter than τ_k is investigated by an analysis of the enhancement seen in the linear relaxation modulus, G⁰(t), as a function of strain and LCB content. This enhancement is seen to (1) increase with increasing strain in all resins, (2) be significantly larger in the sparsely branched HDPE resins relative to the linear HDPE resin, and (3) increase in magnitude with increasing LCB content. The shape and smoothness of the damping function is also investigated. The finite rise time to impose the desired strain is compared to the Rouse relaxation time of linear HDPE resins studied. Sparse LCB is found to increase the magnitude of the relaxation modulus at short times relative to the linear resin. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

Fast pyrolysis bio‐oil as precursor of thermosetting epoxy resins

Fast pyrolysis bio‐oil was employed as a source of phenolic compounds in the production of a bio‐based polymeric network. The bio‐oil was reacted with epichlorohydrin in alkaline medium using benzyltriethylammonium chloride as a phase transfer catalyst. The amount of free phenolic hydroxyl groups before and after modification was quantified through ³¹P‐NMR spectroscopy; and the epoxy content of the bio‐oil upon the chemical functionalization was measured by means of a titration using HBr in acetic acid solution. Grafting of epoxy functions onto the monomer`s structure was studied by FTIR. Likewise, α‐resorcylic acid was also modified with reactive epoxy moieties, and used as low molecular weight comonomer. The epoxidized derivatives of the bio‐oil were cured in epoxy polymers with 4‐dimethylaminopyridine. Thermo‐mechanical characterization showed that the obtained materials behave as thermoset amorphous polymers, exhibiting modulus values ranging from approximately 1.5–3.4 GPa at room temperature and glass transition temperatures above 100°C. POLYM. ENG. SCI., 58:1296–1307, 2018. © 2017 Society of Plastics Engineers     

Polymeric gadolinium chelate–containing magnetic resonance signal‐enhancing coating materials: Synthesis,characterization, and properties

The present investigation deals with studies on novel magnetic resonance signal‐enhancing coating materials. The polyaminocarboxylate complexes of Gd³⁺ as side chains were prepared by the conjugation of N‐(2‐hydroxyethyl)ethylenediaminetriacetic acid (HEDTA) with poly(styrene‐maleic acid) copolymer (SMA). The complexation of the Gd³⁺ ion to the conjugates was carried out by adding GdCl₃ to the solution of the polymer ligands. The resulting Gd³⁺‐containing polymer complexes were characterized by GPC, FTIR, NMR, and inductively coupled plasma–Auger electron spectroscopy, which confirmed that HEDTA was covalently attached to SMA and Gd³⁺‐containing polymer complexes were formed. The PP catheters were coated with the Gd³⁺‐containing polymer complexes and characterized by XPS. The result confirms that the Gd³⁺ complexes were coated on the surface of PP catheters. In the relaxation test, the relaxation rates of the water proton in the vicinity of the coated PP catheter surface increase significantly, suggesting that Gd³⁺‐containing polymer complex coating materials show great MR enhancement of water proton, and potentialities in making catheters used for endovascular interventions or therapy, visible by MRI. The influence of protein on the relaxation rates of coated PP catheter shows that the protein adsorption on the catheter surface influences the enhancement of the MR signal for the coating materials of Gd³⁺‐containing polymer complex. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1358–1364, 2003     

Enhancement of the processing window and performance of polyamide 1010/bio‐based high‐density polyethylene blends by melt mixing with natural additives

This work reports the enhancement of the processing window and of the mechanical and thermal properties of biopolymer blends of polyamide 1010 (PA1010) and bio‐based high‐density polyethylene (bio‐HDPE) at 70/30 (w/w) achieved by means of natural additives. The overall performance of the binary blend melt‐mixed without additives was poor due to both the relatively low thermal stability of bio‐HDPE at the processing temperatures of PA1010, that is, 210–240 °C, and the lack of or poor miscibility between the two biopolymers. Gallic acid, a natural phenolic compound, was added at 0.8 parts per hundred resin (phr) of biopolymer blend to enhance the thermal stability of the green polyolefin and therefore enlarge the processing window of the binary blend. Maleinized linseed oil, a multi‐functionalized vegetable oil, was then incorporated at 5 phr to compatibilize the biopolymers and the performance of the blend was also compared with that of a conventional petroleum‐derived copolymer, namely poly[ethylene‐co‐(acrylic acid)]. The resultant biopolymer blends showed a marked enhancement in thermal stability and also improved toughness when both natural additives were combined. This work can potentially serve as a sound base study for the mechanical recycling of similar blends containing bio‐based but non‐biodegradable polymers. © 2019 Society of Chemical Industry     

Large‐scale equal‐proportional amplification bio‐replication of shark skin Based on solvent‐swelling PDMS

Shark skin has attracted worldwide attention on its superior drag reduction, so‐called shark skin effect. Such marvelous function of shark skin, in particular, is in part related to complicated micro‐riblets. As the creation of natural evolution, micro‐riblets of shark skin act out desirable drag reduction only within range of swimming speed. Over past few years, bio‐replication approach which takes the shark skin as replica template to 1 : 1 transfer surface morphology has been widely applied for drag reduction. However, if application environment remarkably differs from living environment, the drag reduction function is attenuated or even becomes adverse, i.e., the surface structure nonadjustable to ambient environment is obstacle to widespread application of bio‐replication. In this paper, large‐scale equal‐proportional amplification bio‐replication approach is presented to adjust the micro‐riblets of shark skin by taking solvent‐swelling polymer as replica mould. Solvent‐swelling property of polymer is investigated by controlling its swelling ratio to make natural surface function adapting to various application environment. Apart from higher replication accuracy about 95%, experiments show that about 140% solvent‐swelling ratio is achieved at one‐time amplification, and translation of drag reduction peak of natural surface function form living environment to various application environments is ensured by successive large‐scale equal‐proportional bio‐replications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2383–2389, 2013     

Bio‐Based,Self‐Condensed Polyols

A new method for the synthesis of high‐molar‐mass (MM), bio‐based polyols for elastic polyurethanes is developed. This process is based on the self‐condensation of low MM polyols (M_n ≈ 1000) and vacuum removal of the resulting glycerol. Self‐condensation products are hyperbranched estolide polyols with average MMs close to 3000 and hydroxyl numbers in the range of 40–95 mg KOH g^?1. Three polyols, one with primary and two with secondary hydroxyls and different functionalities, are studied. The transesterification proceeded much faster with primary hydroxyls, leading to high‐viscosity products. The effect of functionality and reactivity of starting polyols on properties is discussed. Practical applications: The process is useful for upgrading the existing natural oil‐based polyols to higher MM, lower OH number and variable‐functionality polyols, for expanding application in the urethane field. The process is simple, involving just an oil‐based polyol, a catalyst, and heating under vacuum.     

Catalytic hydrothermal liquefaction of D. tertiolecta for the production of bio‐oil over different acid/base catalysts

In this article, two acid catalysts (ZrO₂/SO₄^2? and HZSM‐5) and two base catalysts (MgO/MCM‐41 and KtB) were used in catalytic hydrothermal liquefaction (HTL) of Dunaliella tertiolecta (D. tertiolecta) for the production of bio‐oil. The results indicated that the acid/base property of the catalyst plays a crucial role in the catalytic HTL process, and the base catalyst is conducive to the improvement of conversion and bio‐oil yield. When KtB was used as the catalyst, the maximum conversion and bio‐oil yield was 94.84 and 49.09 wt %, respectively. The detailed compositional analysis of the bio‐oil was performed using thermogravimetric analysis, elemental analysis, FT‐IR, and GC‐MS. The compositional analysis results showed that the introduction of catalyst is beneficial for reducing the fixed carbon content in the bio‐oil, and the structure of catalyst influences on the bio‐oil composition and boiling point distribution. Based on our results and previous studies, the probable catalytic HTL microalgae model over various catalysts can be described that the main chemical reactions include ketonization, decarboxylic, dehydration, ammonolysis, and so forth. with HZSM‐5 and MgO/MCM‐41 as the catalyst; the cyclodimerization, decomposition, Maillard reaction, and ketonization are the main reactions with ZrO₂/SO₄^2? as the catalyst; the dehydration, ammonolysis, Maillard reaction, and ketonization can occur with KtB as the catalyst. Therefore, a plausible reaction mechanism of the main chemical component in D. tertiolecta is proposed. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1118–1128, 2015     

Improved dielectric properties in A′‐site nickel‐doped CaCu3Ti4O12 ceramics

The improved dielectric properties and voltage‐current nonlinearity of nickel‐doped CaCu₃Ti₄O₁₂ (CCNTO) ceramics prepared by solid‐state reaction were investigated. The approach of A′‐site Ni doping resulted in improved dielectric properties in the CaCu₃Ti₄O₁₂ (CCTO) system, with a dielectric constant ε′≈1.51×10⁵ and dielectric loss tanδ≈0.051 found for the sample with a Ni doping of 20% (CCNTO20) at room temperature and 1 kHz. The X‐ray photoelectron spectroscopy (XPS) analysis of the CCTO and the specimen with a Ni doping of 25% (CCNTO25) verified the co‐existence of Cu⁺/Cu²⁺ and Ti³⁺/Ti⁴⁺. A steady increase in ε′(f) and a slight increase in α observed upon initial Ni doping were ascribed to a more Cu‐rich phase in the intergranular phase caused by the Ni substitution in the grains. The low‐frequency relaxation leading to a distinct enhancement in ε′(f) beginning with CCNTO25 was confirmed to be a Maxwell‐Wagner‐type relaxation strongly affected by the Ni‐related phase with the formation of a core‐shell structure. The decrease of the dielectric loss was associated with the promoted densification of CCNTO and the increase of Cu vacancies, due to Ni doping on the Cu sites. In addition, the Ni dopant had a certain effect on tuning the current‐voltage characteristics of the CCTO ceramics. The present A′‐site Ni doping experiments demonstrate the extrinsic effect underlying the giant dielectric constant and provides a promising approach for developing practical applications.     

Mechanical and thermal properties of bio‐based CaCO3/soybean‐based hybrid unsaturated polyester nanocomposites

Bio‐based calcium carbonate nanoparticles (CaCO₃) were synthesized via size reduction of eggshell powder using mechanical attrition followed by high intensity ultrasonic irradiation. The transmission electron microscopic (TEM) and BET surface area measurements show that these particles are less than 10 nm in size and a surface area of ～44 m²/g. Bio‐based nanocomposites were fabricated by infusion of different weight fractions of as‐prepared CaCO₃ nanoparticles into Polylite® 31325‐00 resin system using a non‐contact Thinky® mixing method. As‐prepared bio‐nanocomposites were characterized for their thermal and mechanical properties. TEM studies showed that the particles were well dispersed over the entire volume of the matrix. Thermal analyses indicated that the bio‐nanocomposites are thermally more stable than the corresponding neat systems. Nanocomposite with 2% by weight loading of bio‐CaCO₃ nanoparticles exhibited an 18°C increase in the glass transition temperature over the neat Polylite 31325 system. Mechanical tests have been carried out for both bio‐nanocomposites and neat resin systems. The compression test results of the 2% Bio‐CaCO₃/Polylite 31325 nanocomposite showed an improvement of 14% and 27% in compressive strength and modulus respectively compared with the neat system. Details of the fabrication procedure and thermal and mechanical characterizations are presented in this article. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1442–1452, 2013     

Physicomechanical and dielectric properties of magnesium and barium ionomers based on sulfonated maleated styrene‐ethylene/butylene‐styrene block copolymer

Ionomers, containing both carboxylate and sulfonate anions on the polymer backbone, based on metal cations like Mg⁺² and Ba⁺² were prepared by sulfonating maleated styrene‐ethylene/butylene‐styrene block copolymer, hereafter referred to as m‐SEBS, followed by its neutralization by metal acetates. Infrared spectroscopic studies reveal that sulfonation reaction takes place in the para position of the benzene rings of polystyrene blocks and metal salts are formed on neutralization of the precursor acids. Dynamic mechanical thermal analyses show that sulfonation causes increase in T_g of the rubbery phase of m‐SEBS and decrease in tan δ at T_g of the hard phase, along with formation of a rubbery plateau. The changes become more pronounced on neutralization of the sulfonated maleated SEBS, and the effect is greater in the case of Ba salt. Dielectric thermal analyses (DETA) show that incorporation of ionic groups causes profound changes in the dielectric constant (ϵ′) of m‐SEBS. In addition to the low temperature glass–rubber transition, the plot of ϵ′ vs. temperature shows occurrence of a high‐temperature transition, also known as the ionic transition. Activation energy for the dielectric relaxation could be determined on the basis of frequency dependence of the ionic transition temperature. Two values of the activation energy for the dielectric relaxation refer to the presence of two types of ionic aggregates, namely multiplets and clusters. Incorporation of the ionic groups causes enhancement in stress–strain properties as well as retention of the properties at elevated temperatures (50° and 75°C), and the effect is more pronounced in the case of Ba ionomer. Although sulfonated ionomers show greater strength than the carboxylated ionomers, the sulfonated maleated ionomers show higher stress–strain properties in comparison to both sulfonated and carboxylated ionomers. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 816–825, 2000     

Two‐Step Protein Labeling by Using Lipoic Acid Ligase with Norbornene Substrates and Subsequent Inverse‐Electron Demand Diels–Alder Reaction

Inverse‐electron‐demand Diels–Alder cycloaddition (DA_inv) between strained alkenes and tetrazines is a highly bio‐orthogonal reaction that has been applied in the specific labeling of biomolecules. In this work we present a two‐step labeling protocol for the site‐specific labeling of proteins based on attachment of a highly stable norbornene derivative to a specific peptide sequence by using a mutant of the enzyme lipoic acid ligase A (LplA^W37V), followed by the covalent attachment of tetrazine‐modified fluorophores to the norbornene moiety through the bio‐orthogonal DA_inv . We investigated 15 different norbornene derivatives for their selective enzymatic attachment to a 13‐residue lipoic acid acceptor peptide (LAP) by using a standardized HPLC protocol. Finally, we used this two‐step labeling strategy to label proteins in cell lysates in a site‐specific manner and performed cell‐surface labeling on living cells.     

Synthesis of hydroxyl‐terminated copolymer of styrene and 4‐vinylpyridine via nitroxide‐mediated living radical polymerization

The random copolymers of styrene (St) and 4‐vinylpyridine (4‐VP) with hydroxyl end group and low polydispersities were synthesized by nitroxide‐mediated living radical polymerization initiated by azobisisobutyronitrile (AIBN) and 4‐hydroxyl‐2,2,6,6–tetramethylpiperidine‐oxyl (TEMPO‐OH). The experimental results have shown that all synthesized copolymers have narrow molecular weight distribution. The conversion of monomers and the molecular weight of copolymer increased with polymerization time. The copolymerization rate is affected by molar ratios of HTEMPO to AIBN. ¹H‐Nuclear magnetic resonance spectra shows that one end of copolymers was capped by TEMPO‐OH moiety. The use of this method permits the copolymer with hydroxyl chain end and controllable molecular weight and molecular weight distribution. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1842–1847, 2004     

Condition monitoring of a thermally aged hydroxy‐terminated polybutadiene (HTPB)/isophorone diisocyanate (IPDI) elastomer by nuclear magnetic resonance cross‐polarization recovery times

A hydroxy‐terminated polybutadiene (HTPB)/isophorone diisocyanate (IPDI) elastomer is commonly used as propellant binder material. The thermal degradation of the binder is believed to be an important parameter governing the performance of the propellant. The aging of these binders can be monitored by mechanical property measurements, such as modulus or tensile elongation. These techniques, however, are not easily adapted to binder agents that are dispersed throughout a propellant. In this paper we investigated solid‐state nuclear magnetic resonance (NMR) relaxation times as a means to predict the mechanical properties of the binder as a function of aging time. Proton (¹H) spin–lattice and spin–spin relaxation times were insensitive to the degree of thermal degradation of the elastomer. Apparently, these relaxation times depend on localized motions that are only weakly correlated with mechanical properties. A strong correlation was found between the ¹³C cross‐polarization (CP) NMR time constant, T_cp, and the tensile elongation at break of the elastomer as a function of aging time. A ramped‐amplitude CP experiment was less sensitive to imperfections in setting critical instrumental parameters for this mobile material. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 453–459, 2001