Synthesis and characterization of a series of smectic liquid crystalline elastomers

A series of new smectic and cholesteric liquid crystalline elastomers was prepared by graft polymerization of mesogenic monomer with the chiral and nonmesogenic crosslinking agent using polymethylhydrosiloxane as backbone. The chemical structures of the monomers and polymers obtained were confirmed by Fourier transform infrared (FTIR), proton nuclear magnetic resonance spectra (¹H‐NMR). The mesomorphic properties were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X‐ray diffraction measurements (XRD). M₁ showed smectic (S_B, S_C, S_A) and nematic phases during the heating and the cooling cycles. Polymer P₀ and elastomer P₁ exhibited smectic B phase, elastomers P₂–P₅ showed smectic A phase, P₆ and P₇ showed cholesteric phase, and P₈ displayed stress‐induced birefringence. The elastomers containing less than 15 mol % M₂ displayed elasticity and reversible phase transition with wide mesophase temperature ranges. Experimental results demonstrated that the glass transition temperatures decreased first and then increased; melting temperatures and the isotropization temperatures and the mesophase temperature ranges decreased with increasing content of crosslinking unit. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 498–506, 2005     

Synthesis and properties of side‐chain liquid‐crystalline polysiloxanes containing hemiphasmidic mesogens

The synthesis of hemiphasmidic monomers 4‐[(3,4,5‐triethoxy)benzoyloxy]‐4′‐[(p‐allyloxy)benzoyloxy]biphenyl (M₁), 4‐[(3,5‐diethoxy)benzoyloxy]‐4′‐[(p‐allyloxy)‐benzoyloxy]biphenyl (M₂), and of the corresponding side‐chain liquid‐crystalline polysiloxanes (P₁, P₂) was carried out. For comparison, rodlike monomer 4‐[(p‐ethoxy)‐benzoyloxy]‐4′‐[(p‐allyloxy)benzoyloxy]biphenyl (M₃) and its polysiloxanes (P₃) were also prepared. The chemical structures of the monomers and polymers obtained were confirmed by FTIR and ¹H‐NMR spectra. Their mesomorphic properties and phase behavior were investigated by differential scanning calorimetry, polarizing optical microscopy, and X‐ray diffraction measurements. The relationship between structures and properties was discussed. It was observed that M₁ and M₃ were enantiotropic nematic phase, M₂ was monotropic mesophase, and their poly(methylsiloxanes) (P₁–P₃) possessed a broad range enantiotropic nematic phases and high thermal stability. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 946–952, 2005     

Side‐chain copolymers containing smectic monomer and chiral reagent—Synthesis and characterization

A series of new chiral side‐chain liquid‐crystalline polymers were prepared containing smectic‐nematic monomer and nonmesogenic chiral monomer. All polymers were synthesized by graft polymerization using polymethylhydrosiloxane as backbone. The mesomorphic properties were investigated by differential scanning calorimetry, polarizing optical microscopy, thermogravimetric analyses, and X‐ray diffraction measurements. The chemical structures of the monomers and polymers obtained were confirmed by Fourier transform infrared, proton nuclear magnetic resonance spectra (¹H NMR). M₁ showed smectic (S_B, S_C) and nematic phase on the heating and the cooling cycle. Polymers P₀–P₂ were in chiral smectic A phase, while P₃–P₅ were in cholesteric phase, P₆ has bad LC properties, and P₇ has no LC properties. Experimental results demonstrated that nonmesogenic chiral moiety and LC mesogenic with long carbochain offered the possibility of application because of its lower glass transition temperature, and the glass transition temperatures and isotropization temperatures and the ranges of the mesophase temperature reduced with increasing the contents of chiral agent. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of side‐chain liquid‐crystalline elastomers containing cholesterol

A series of new smectic and cholesteric liquid‐crystalline elastomers were prepared by graft polymerization of mesogenic monomer with the chiral and nonmesogenic crosslinking agent using polymethylhydrosiloxane as backbone. The chemical structures of the monomers and polymers obtained were confirmed by Fourier transform infrared and proton nuclear magnetic resonance spectra. The mesomorphic properties were investigated by differential scanning calorimetry, polarizing optical microscopy, and X‐ray diffraction measurements. M₁ showed cholesteric phase during the heating and the cooling cycle. Polymer P₁, elastomers P₂ and P₃ exhibited smectic phase, elastomers P₄? P₆ showed chiral smectic C phase, P₇ showed cholesteric phase, and P₈ displayed stress‐induced birefringence. The elastomers containing less than 15 mol % M₂ displayed elasticity and reversible phase transition with wide mesophase temperature ranges. Experimental results demonstrated that the glass transition temperatures, the isotropization temperatures, and the mesophase temperature ranges decreased with increasing content of the crosslinking unit. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 383–390, 2005     

Mesomomorphism enhancement of modified side‐chain liquid‐crystalline polysiloxanes by copolymerization

The liquid‐crystalline (LC) monomer 4‐allyoxybenzoyloxy‐4′‐buthylbenzoyloxy‐p‐phenyl (M₁), whose LC phase appeared at lower temperatures, from 137 to 227°C, and the modified mesogenic monomer 4‐allyoxybenzoyloxy‐4′‐methyloxybenzoyloxy‐p‐biphenyl (M₂), whose LC phase appeared at higher temperatures, from 185 to 312°C, were prepared. A series of side‐chain LC polysiloxanes containing M₁ and M₂ were prepared by graft copolymerization. Their LC properties were characterized by differential scanning calorimetry, thermogravimetric analysis, polarizing optical microscopy, and X‐ray diffraction. The results show that the introduction of the modified mesogenic monomer M₂ into the polymeric structure caused an additional increase in the clearing point (isotropic transition temperature) of the corresponding polysiloxanes, compared with unmodified polysiloxanes, but did not significantly affect the glass‐transition temperature. Moreover, the modified polysiloxanes exhibited nematic phases as the unmodified polymer did. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1196–1201, 2005     

Liquid crystalline properties of cholesteric elastomers based on a mesogenic monomer containing menthyl groups

A new chiral mesogenic monomer (M_LC) based on menthyl groups and the corresponding cholesteric elastomers (LCE₁–LCE₃) were prepared. Their chemical structures and purity were characterized by Fourier transform infrared, nuclear magnetic resonance and elemental analyses. The liquid crystalline properties were investigated by differential scanning calorimetry, polarizing optical microscopy, thermogravimetric analysis and X‐ray diffraction. The selective reflection of light for M_LC was characterized with ultraviolet/visible/near infrared. The effect of the content of crosslinking units on the liquid crystalline behaviour of LCE₁–LCE₃ is discussed. The experimental results show that the chiral monomer and the corresponding elastomers containing menthyl groups can show mesomorphism when a flexible linkage chain is inserted between the mesogenic core and the bulky terminal menthyl fragments to reduce the steric effect. M_LC exhibited a chiral smectic C phase, a cholesteric phase and a cubic blue phase. LCE₁–LCE₃ with a low content of crosslinking units showed a cholesteric phase because of the introduction of the nematic crosslinking unit. With increasing content of crosslinking units, the corresponding glass transition temperature increased, while the clearing temperature decreased. Thermogravimetric analysis showed that LCE₁–LCE₃ have good thermal stability. Copyright © 2012 Society of Chemical Industry     

Main‐chain chiral smectic liquid‐crystalline ionomers containing sulfonic acid groups

Three series of main‐chain liquid‐crystalline polymers (P1, P2, and P3) were synthesized by an interfacial condensation reaction of sebacoyl dichloride with various amount of brilliant yellow, isosorbide, and 4,4′‐biphenydiol. P1 series are polyesters prepared from sebacoyl chloride and various amount of 4,4′‐biphenyldiol and isosorbide. P2 series are polyesters prepared from sebacoyl chloride and various amount of 4,4′‐biphenyldiol, brilliant yellow, and isosorbide. P3 series are polyesters prepared from sebacoyl chloride and various amount of 4,4′‐biphenyldiol and brilliant yellow. P2 and P3 are main‐chain liquid‐crystalline ionomers. P1₂ and P3 series were prepared as model polymers for comparison with the liquid crystalline behavior of ionomers, P2 series. The structures of the polymers were characterized by IR and UV spectroscopy. Differential scanning calorimetry was used to measure the thermal properties of the polymers. The mesogenic properties were investigated by polarized optical microscope, differential scanning calorimetry, and X‐ray diffraction measurements. The results show that P2 series are chiral smectic C (S_mC*) and chiral smectic B (S_mB*) liquid crystalline ionomers exhibiting broken focal‐conic texture and schlieren, as is the polymer P1₂, which has the same amount of 4,4′‐biphenydiol and isosorbide. The introduction of ionic units in P2 series leads to an increase of clearing point, but has not affected the mesogenic type and texture, as compared with the corresponding polymer P1₂. The introduction of chiral units in P2 series leads to a change of mesophase, as compared with P3 series, which exhibit smectic C mesogetic phase. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1254–1263, 2006     

Preparation of novel acrylate‐based liquid crystalline polymers and the photoinduced alignment behavior of their films

Two acrylate monomers containing both mesogenic biphenyl group and photoreactive cinnamoyl group as well as different length of flexible spacers (i.e., n‐[4′‐(n‐cinnamoyloxyalkoxy)biphenyl‐4‐yloxy]alkyl acrylate, n = 4 (A4OO4C) and 6 (A6OO6C)) were synthesized for the first time. Their corresponding polymers (i.e., PA4OO4C and PA6OO6C) were obtained by free radical polymerization using AIBN as an initiator. The monomer A4OO4C showed smectic liquid crystalline phase and a clear fan texture was observed under optical polarizing microscope. However, no liquid crystalline phase was found for A6OO6C. In contrast, PA4OO4C showed no liquid crystalline phase while PA6OO6C showed a clear nematic schlieren texture during the cooling process. The optical polarized microscope of E5 cast on the top of the polymer film also showed the alignment. Furthermore, the irradiation of the polymer films by LP‐UV light led to the cycloaddition of the cinnamoyl groups, resulting in the simultaneous alignment of the biphenyl groups. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4565–4572, 2006     

Effect of the length of the carbochain on the phase behavior of side‐chain cholesteric liquid‐crystalline elastomers

In this study, we prepared two series of new side‐chain cholesteric liquid‐crystalline elastomers (PI and PII) derived from the same chiral bisolefinic crosslinking units and different nematic liquid‐crystalline monomers. The chemical structures of the monomers and polymers obtained were confirmed by Fourier transform infrared and ¹H‐NMR spectroscopy. The phase behavior properties were investigated by differential scanning calorimetry, thermogravimetric analysis, and polarizing optical microscopy. The effect of the length of the carbochain on the phase behavior of the elastomers was investigated. The polymers of the PI and PII series showed similar properties. Polymer P₁ showed a nematic phase, P₂–P₇ showed a cholesteric phase, and P₄–P₇, with more than 6 mol % of the chiral crosslinking agent, exhibited a selective reflection of light. The elastomers containing less than 15 mol % of the crosslinking units displayed elasticity, a reversible phase transition with wide mesophase temperature ranges, and a high thermal stability. The experimental results demonstrate that the glass‐transition temperatures first decreased and then increased; the isotropization temperatures and the mesophase temperature ranges decreased with increasing content of crosslinking agent. However, because of the different lengths of the carbochain, the glass‐transition temperatures and phase‐transition temperatures of the PI series were higher than those of the PII series, and the PI and PII elastomers had their own special optical properties. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1204–1210, 2005     

Synthesis and structure of polysiloxane liquid crystalline elastomers with a mesogenic crosslinking agent

A new mesogenic crosslinking agent M‐1 was synthesized to minimize the perturbations of a nonmesogenic crosslinking agent for liquid crystalline elastomers. The synthesis of new side‐chain liquid crystalline elastomers containing a rigid mesogenic crosslinking agent M‐1 and a nematic monomer M‐2 is described by a one‐step hydrosilylation reaction. The chemical structures of the obtained monomers and elastomers were confirmed by ¹H NMR and FTIR spectroscopy. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry, polarizing optical microscopy, and X‐ray diffraction measurements. The influence of the crosslinking units on the phase behavior is discussed. The elastomers containing less than 15 mol % of the crosslinking units showed elasticity, reversible phase transition, and nematic‐threaded texture. However, when the crosslinking density reached 21.6 mol %, the mesophase of polymer P‐8 disappears. The adoption of a mesogenic crosslinking agent diminishes the perturbation of a nonmesogenic crosslinking agent on mesophase of liquid crystalline elastomers, and isotropic temperature and a mesomorphic temperature range slightly decreased with increasing content of the crosslinking agent. In addition, X‐ray analysis shows nematic polydomain network polymers can transform into smectic monodomain by stress induction, leading to the orientation formation macroscopically. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1736–1742, 2004     

Synthesis and characterization of new ferroelectric liquid‐crystalline cyclic oligosiloxanes containing methyleneoxymethylene spacers

The synthesis of side‐chain liquid‐crystalline oligocyclosiloxanes containing methyleneoxymethylene spacers, two different mesogenic cores (including biphenyl phenyl carboxylate or biphenyl fluorophenyl carboxylate groups) and chiral tails is presented. Differential scanning calorimetry, optical polarizing microscopy and X‐ray diffraction measurements reveal liquid‐crystalline properties for all of the synthesized monomers and oligomers. All cyclic oligosiloxanes exhibit enantiotropic smectic A and chiral smectic C phases. The mesogenic properties of the cyclic oligomers and side‐chain liquid‐crystalline precursor are discussed. Copyright © 2005 Society of Chemical Industry     

Effect of mesogenic crosslinking units on the mesomorphic phases of cholesteric liquid crystalline polymers

A series of cyclosiloxane‐based cholesteric liquid crystalline polymers were synthesized from cholest‐5‐en‐3‐ol (3β)‐4‐(2‐propenyloxy)benzoate and a nematic crosslinking monomer biphenyl‐4,4′‐diol bis[4‐(2‐propenyloxy)‐benzoate], containing mesogenic crosslinking contents among 0–7.8 wt %. Swelling experiments of the elastomers were employed to determine the effective crosslink density (M_c). With increase of mesogenic crosslinking component in the polymers, the isotropic temperature decreases, but both the temperature of glass transition and melting point change irregularly. All the polymers have high thermal stability and percentage weight loss occurred at 460°C decreases with increase of crosslinking units. The intensity of X‐ray diffraction peak at 2θ ≈ 17° decreases with increase of mesogenic crosslinking units, suggesting that the order between two neighbor liquid crystalline molecules disturbed by the mesogenic crosslinking agents. The maximum reflection bands shift slightly to long wavelength and become broad, indicating that the helical structure is partially disrupted because of both the constraint of chemical crosslinking agents and the different mesogenic units. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1161–1168, 2007     

New side‐chain nematic liquid crystalline elastomers containing smectic crosslinking units

A series of siloxane‐based liquid crystalline elastomers containing the smectic crosslinking agent M‐1 and nematic monomer M‐2 were synthesized by a one‐step hydrosilication reaction. The chemical structures of the monomers and polymers obtained were confirmed by FTIR spectroscopy. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X‐ray diffraction (XRD) measurements. The influence of the crosslinking unit on the phase behavior was discussed. The experimental results demonstrated that the glass transition temperatures of elastomers had no remarkable change, and isotropization temperatures decrease with increasing the content of the crosslinking agent M‐1. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3755–3760, 2004     

EDTA and pH‐sensitive crosslinking polymerization of acrylic acid, 2‐acrylamidoglycolic acid,and 2‐acrylamide‐2‐methyl‐1‐propanesulfonic acid

Network formation was monitored by shear storage modulus (G′) during free radical crosslinking polymerization to investigate the effects of pH and ethylenediaminetetraacetic acid (EDTA; a complex agent). Three types of acrylic monomers, acrylic acid (AAc), 2‐acrylamidoglycolic acid (AmGc), and 2‐acrylamido‐2‐methyl propanesulfonic acid (AmPS), were polymerized in the presence of a crosslinking agent. The ratio of crosslinking agent (methylene bis‐acrylamide; MBAAm) to monomer was varied as: 0.583 × 10^?3, 1.169 × 10^?3, 1.753 × 10^?3, and 2.338 × 10^?3. G′ of the hydrogel in crosslinking polymerizations of AAc and AmPS was effectively increased by addition of EDTA, which was not the case for the crosslinking polymerization of AmGc. The order of magnitude of G′ differed based on the acidity of monomer. The maximum values of G′ in crosslinking polymerizations of AAc, AmGc, and AmPS were ～20,000 Pa, 6000 Pa, and 400 Pa, respectively. G′ varied linearly with the molecular weight between crosslinks (M_wc). pH and EDTA‐complex affected the rate of intramolecular propagation during crosslinking polymerization. Our results indicated that G′ was primarily affected by the following factors in the order: (1) acidity of monomer, (2) M_wc, and (3) physical interactions induced by pH and EDTA. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41026.     

Synthesis and phase behavior of nematic liquid‐crystalline elastomers derived from smectic crosslinking agent

A mesogenic crosslinking agent M‐1 was synthesized to minimize the perturbations of nonmesogenic crosslinking agent for liquid‐crystalline elastomers. The synthesis of side‐chain liquid‐crystalline elastomers containing a rigid mesogenic crosslinking agent M‐1 and a nematic monomer M‐2 was described by a one‐step hydrosilylation reaction. The chemical structures of the obtained monomers and network polymers were confirmed by Fourier transform infrared and ¹H‐NMR spectroscopy. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry, polarizing optical microscopy, and X‐ray diffraction measurements. The influence of the crosslinking units on the phase behavior was discussed. The liquid‐crystalline elastomers containing less than 15 mol % of the crosslinking units showed elasticity, reversible phase transition, and threaded texture. The experimental results demonstrated that isotropic temperature and liquid‐crystalline range of polymers P‐1–P‐7 decreased a little as the concentration of crosslinking agent M‐1 increased, and the use of mesomorphic crosslinking agent M‐1 promotes the arrangement of liquid‐crystalline units from P‐1 to P‐5. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1712–1719, 2005     

Phase behavior of side‐chain liquid‐crystalline elastomers and their precursors containing para‐nitro azobenzene

Side‐chain liquid‐crystalline copolymethacrylates (PMm's), containing para‐nitro azobenzene as the mesogenic group and 2‐hydroxylethyl methacrylate (HEMA) as a comonomer, were synthesized by radical polymerization, and their corresponding liquid‐crystalline elastomers (LCEm's) were prepared through chemical crosslinking. All of the polymers (PMm's) and the elastomers studied showed enantiotropic smectic A phases; the clearing temperature (T_i) of the PMm polymers decreased with increasing amount of HEMA, and the T_i of the corresponding LCEm's decreased compared to that of their precursors. Small‐angle X‐ray scattering studies on the copolymers quenched from their liquid‐crystalline phases indicated that the characteristic distance increased with increasing amorphous component content and thus, the amorphous components were in between the smectic layers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2275–2279, 2003     

New side‐chain liquid‐crystalline ionomers. I. Synthesis and characterization of a homopolymer derived from ionic mesogenic groups

Liquid‐crystalline monomer cholesteryl 4‐allyloxybenzoate (M₁), new ionic mesogenic monomer cholesteryl 4‐allyloxy‐3‐(potassium sulfonate)benzoate (M₂), and corresponding polymer P₁ and ionomer P₂ were synthesized. The chemical structures of the monomers and homopolymer were confirmed with Fourier transform infrared and ¹H‐NMR spectroscopy. The mesogenic properties were studied with differential scanning calorimetry, thermogravimetric analysis, polarizing optical microscopy, and X‐ray diffraction measurements. The effect of the ionic units on the phase behavior was examined. M₁ showed a cholesteric phase, and M₂ revealed a smectic A phase. P₁ and P₂ displayed smectic A phases. The experimental results demonstrated that the addition of ionic units to the mesogenic molecule not only affected the phase‐transition temperature but also changed the mesogenic phase type. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2511–2516, 2004     

Synthesis and characterization of chiral side‐chain liquid‐crystalline polymer containing menthol ester

The synthesis of new chiral side‐chain liquid‐crystalline polysiloxanes containing p‐(allyoxy)benzoxy‐p‐chlorophenyl (ABCH) as mesogenic units and undecylenic acid menthol ester (UM) as chiral nonmesogenic units is presented. The chemical structures of monomers and polymers are confirmed by IR spectroscopy. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) are used to measure thermal properties of those polymers. Mesogenic properties are characterized by polarized optical microscope (POM), DSC, and small‐angle X‐ray diffraction. Analytic results revealed that polymers P₀–P₆ are thermotropic liquid‐crystalline polymers with low glass transition; Polymers P₂–P₆ exhibit chiral smectic liquid‐crystalline properties with marble texture, optical rotation, and a sharp reflection at low angles in X‐ray diffraction; polymers P₀, P₁ only exhibit smectic liquid‐crystalline properties without chirality; and P₇ only exhibits chirality without liquid‐crystalline properties. All the polymers exhibit good thermal stability with temperature of 5% mass loss over 297°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2845–2851, 2003     

Synthesis and characterization of side‐chain liquid‐crystalline ionomers containing quaternary ammonium salt groups

A series of thermotropic side‐chain liquid‐crystalline ionomers (LCIs) containing 4‐(4‐alkoxybenzyloxy)‐4′‐allyloxybiphenyl (M) as mesogenic units and allyl triethylammonium bromide (ATAB) as nonmesogenic units were synthesized by graft copolymerization upon polymethylhydrosiloxane. The chemical structures of the polymers were confirmed by IR spectroscopy. DSC was used to measure the thermal properties of these polymers. The mesogenic properties were characterized by polarizing optical microscopy, DSC, and X‐ray diffraction. Homopolymers without ionic groups exhibit smectic and nematic mesophases. The nematic mesophases of the ionomers disappear and the mesomorphic temperature ranges decrease with increasing concentration of ionic units. The influence of the alkoxy chain length on clearing temperature (T_c) values of ionomers clearly shows an odd‐even effect, similar to that of other side‐chain liquid‐crystalline polymers. The mesomorphic temperature ranges increase with increasing alkoxy chain length when the number of alkoxy carbon is over 3. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2879–2886, 2003     

Simulation study on the liquid‐crystalline ordering and fluidity of energetic diblock copolymers based on poly[3,3‐bis(azidomethyl) oxetane]

The liquid‐crystalline ordering and fluidity of energetic diblock copolymers based on poly[3,3‐bis(azidomethyl) oxetane] (BAMO) and 3‐nitratomethyl‐3′‐methyloxetane (NMMO) were investigated by the dissipative particle dynamics method. The results show that these copolymers, with moderate BAMO block lengths (x's), experienced the disorder, nematic, and smectic phases with decreasing temperature. The nematic phase was suppressed when the rod length was too long or short. After the formation of the smectic phase, the fluidity had a sharp decline. The temperature forming the smectic phase was defined as the order–disorder transition temperature (T_ODT) and depended strongly on x. A simple scaling rule, T_ODT ≈ e^?x, between T_ODT and x was constructed. The effect of the soft NMMO block fraction on the fluidity emerged before the formation of the smectic phase. These results can help researchers design and synthesize new energetic copolymers with an appropriate melting temperature range for use as binders of solid propellants. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013