Synthesis of Poly(methyl‐co‐trifluoropropyl)silsesquioxanes and Their Thin Films for Low Dielectric Application

Poly(methyl‐co‐trifluoropropyl)silsesquioxanes (P(M‐co‐TFP)SSQs) were prepared using methyltrimethoxysilane (MTMS) and trifluoropropyltrimethoxysilane (TFPTMS). The molecular weight, microstructure of the copolymers and properties of their thin films have been changed by adjusting reaction parameters such as the molar ratio of water to silane, the molar ratio of catalyst to silane, reaction time, solvent content, and temperature. The refractive index of the copolymer thin film decreased from 1.404 to ca. 1.348 as curing temperature was increased to 420 °C. The dielectric constant of the film decreased with an increase of the molecular weight of the copolymer, and the lowest dielectric constant obtained was ca. 2.2. Hardness and elastic modulus of the thin films were 0.7 and 5 GPa, respectively. Crack velocity was measured to be 10^?11 m/s at the film thickness of around 0.9 μm under aqueous environment.

     

Preparation of siloxane–silsesquioxane hybrid thin films for large‐scale‐integration interlayer dielectrics with excellent mechanical properties and low dielectric constants

Several kinds of homogeneous organic–inorganic hybrid polymer thin films were designed with improved mechanical properties and low dielectric constants (<3.0). Novel soluble siloxane–silsesquioxane hybrid polymers were synthesized with cyclic and/or cage silane monomers, which had triorganosiloxy (R₃Si_1/2), diorganosiloxane (R₂SiO_2/2), and organosilsesquioxane (RSiO_3/2) moieties with ethylene bridges at the molecular level, by the hydrolysis and condensation of 2,4,6,8‐tetramethyl‐2,4,6,8‐tetra(trimethoxysilylethyl)cyclotetrasiloxane (a cyclic monomer). The electrical properties of these films, including the dielectric constant (～2.51), leakage current (6.4 × 10^?11 A/cm² at 0.5 MV/cm), and breakdown voltage (～5.4 MV/cm) were fairly good. Moreover, the mechanical properties of the hybrid films, including the hardness (～7 GPa), modulus (～1.2 GPa), and crack‐free thickness (<2 μm), were excellent in comparison with those of previous spin‐on‐glass materials with low dielectric constants. The excellent mechanical properties were proposed to be due to the high contents of Si? OH groups (>30%) and the existence of ethylene bridge and siloxane moieties in the hybrid polymer precursors. In addition, the mechanical properties of the hybrid films were affected by the contents of the cagelike structures. The more cagelike structures a hybrid film contained, the worse its mechanical properties were. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 626–634, 2003     

Chitosan‐modified d‐α‐tocopheryl poly(ethylene glycol) 1000 succinate‐b‐poly(ε‐caprolactone‐ran‐glycolide) nanoparticles for the oral chemotherapy of bladder cancer

Oral chemotherapy is quickly emerging as an appealing option for cancer patients. It is less stressful because the patient has fewer hospital visits and can still maintain a close relationship with health care professionals. Three kinds of nanoparticles made from commercial poly(ε‐caprolactone) (PCL) and self‐synthesized d‐α‐tocopheryl poly(ethylene glycol) 1000 succinate ‐b‐poly(ε‐caprolactone‐ran‐glycolide) [TPGS‐b‐(PCL‐ran‐PGA)] diblock copolymer were prepared in this study for the oral delivery of antitumor agents, including chitosan‐modified PCL nanoparticles, nonmodified TPGS‐b‐(PCL‐ran‐PGA) nanoparticles, and chitosan‐modified TPGS‐b‐(PCL‐ran‐PGA) nanoparticles. First, the TPGS‐b‐(PCL‐ran‐PGA) diblock copolymer was synthesized and structurally characterized. Chitosan was adopted to extend the retention time at the cell surface and thus increase the chance of nanoparticle uptake by the gastrointestinal mucosa and improve the absorption of drugs after oral administration. The resulting TPGS‐b‐(PCL‐ran‐PGA) nanoparticles were found to be of spherical shape and around 200 nm in diameter with a narrow size distribution. The surface charge of the TPGS‐b‐(PCL‐ran‐PGA) nanoparticles could be reversed from anionic to cationic after surface modification. The chitosan‐modified TPGS‐b‐(PCL‐ran‐PGA) nanoparticles displayed a significantly higher level of cellular uptake compared with the chitosan‐modified PCL nanoparticles and nonmodified TPGS‐b‐(PCL‐ran‐PGA) nanoparticles. In vitro cell viability studies showed the advantages of the chitosan‐modified TPGS‐b‐(PCL‐ran‐PGA) nanoparticles over Taxol in terms of their cytotoxicity against human RT112 cells. In summary, the oral delivery of antitumor agents by chitosan‐modified TPGS‐b‐(PCL‐ran‐PGA) nanoparticles produced results that were promising for the treatment of patients with bladder cancer. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2118–2126, 2013     

Effects of synthesis‐solvent composition and initiator concentration on the swelling behaviour of poly(N‐isopropylacrylamide) P(NIPAAM), poly(NIPAAM‐co‐dimethyl itaconate), and poly(NIPAAM‐co itaconic acid) gels

The effects of synthesis‐solvent composition, initiator concentration, comonomer type and monomer purity on the volume swelling ratios, and polymer‐solvent interaction parameter χ have been investigated as a function of temperature. Non‐ionic N‐isopropylacrylamide (NIPAAM) homopolymer gels, poly[NIPAAM‐co‐(dimethyl itaconate)] (P(NIPAAM‐co‐DMI)) and poly[NIPAAM‐co‐(itaconic acid)] (P(NIPAAM‐co‐IA)) gels containing hydrophobic (DMI) and hydrophilic (IA) comonomers were prepared by free radical polymerization using potassium persulfate (KPS) –N, N, N′, N′‐tetramethyl ethylene diamine (TEMED) (redox initiator) in the presence of an N, N′‐methylene bis(acrylamide) (MBAAM) cross‐linking agent. The synthesis‐solvent composition (40/60 mixture of water/methanol and water) and initiator concentration employed significantly affected the properties of the NIPAAM gels. The transition temperatures of P(NIPAAM‐co‐IA) gels synthesized in water/methanol mixture were higher than that of the gel obtained in water. Furthermore, χ values of the NIPAAM homopolymer gel prepared with higher KPS content was an increasing function of temperature, while χ values of the sample obtained with lower initiator concentration changed around a critical solubility value 0.50. The results obtained also show that the interactions between monomer and solvent molecules in the reaction media (ie composition of the pregel solution) have an important effect on the formation and properties of the network structure (ie pore sizes of the gels). © 2000 Society of Chemical Industry     

Nanoporous Low Dielectric Cyclosiloxane Bearing Polysilsesquioxane Thin Films Templated by Poly(ε‐caprolactone)

Summary: Dielectric cyclosiloxane bearing polysilsesquioxanes (CS‐PSSQs) were prepared by acid catalyzed polymerization using 2,4,6,8‐tetramethyl‐2,4,6,8‐tetra(trimethoxysilylethyl)cyclotetrasiloxane. The molecular weight, and content of the functional end‐groups of the CS‐PSSQs were found to be dependent on the process parameters, such as the molar ratio of water and catalyst to the ? OCH₃ group of the silane monomer, the amount of solvent, and the poly(ε‐caprolactone) (PCL) content, etc. Based on these CS‐PSSQ prepolymers, nanoporous organic/inorganic hybrid thin films were fabricated by spin‐coating mixtures of these prepolymers with star‐shaped PCL on the silicon substrate, and subsequently heating them at 150 and 250 °C for 1 minute each and then at 420 °C for 1 hour. A dielectric constant as low as 2.28 was achieved for the nanoporous PCL/CS‐PSSQ (3:7 v/v) film, along with low moisture absorption in ambient and water conditions, primarily due to the presence of hydrophobic moieties such as ethylene and methyl groups of the polymer and nano‐sized hydrophobic pores inside the matrix, resulting in the film having stable dielectric properties. Moreover, the PCL/CS‐PSSQ (3:7 v/v) nanohybrid film revealed a nanoporous structure containing ca. 1.52 nm of average‐sized mesopores, as measured by the N₂ adsorption method. The CS‐PSSQ‐only film showed high mechanical strengths having an elastic modulus and hardness of 6.64 and 0.88 GPa, respectively, for the 7 500 Å thick film and 2.41 and 0.38 GPa, respectively, for the PCL/CS‐PSSQ (3:7 v/v) film. In addition, the crack velocity of the CS‐PSSQ‐only film was found to be ca. 10^?11 m · s^?1 in ambient conditions and an aqueous environment, probably due to the enhanced hydrophobicity and mechanical toughness of the incorporated methyl group, siloxane unit and ethylene moieties in the polymer matrix.

     

Transparent poly(methyl methacrylate‐co‐butyl acrylate) nanofibers

Nanofibers of n‐Butyl Acrylate/Methyl Methacrylate copolymer [P(BA‐co‐MMA)] were produced by electrospinning in this study. P(BA‐co‐MMA) was synthesized by emulsion polymerization. The structural and thermal properties of copolymers and electrospun P(BA‐co‐MMA) nanofibers were analyzed using Fourier transform infrared spectroscopy–Attenuated total reflectance (FTIR–ATR), Nuclear magnetic spectroscopy (NMR), and Differential scanning calorimetry (DSC). FTIR–ATR spectra and NMR spectrum revealed that BA and MMA had effectively participated in polymerization. The morphology of the resulting nanofibers was investigated by scanning electron microscopy, indicating that the diameters of P(BA‐co‐MMA) nanofibers were strongly dependent on the polymer solution dielectric constant, and concentration of solution and flow rate. Homogeneous electrospun P(BA‐co‐MMA) fibers as small as 390 ± 30 nm were successfully produced. The dielectric properties of polymer solution strongly affected the diameter and morphology of electrospun polymer fibers. The bending instability of the electrospinning jet increased with higher dielectric constant. The charges inside the polymer jet tended to repel each other so as to stretch and reduce the diameter of the polymer fibers by the presence of high dielectric environment of the solvent. The extent to which the choice of solvent affects the nanofiber characteristics were well illustrated in the electrospinning of [P(BA‐co‐MMA)] from solvents and mixed solvents. Nanofiber mats showed relatively high hydrophobicity with intrinsic water contact angle up to 120°. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4264–4272, 2013     

Preparation of acrylamide‐based poly‐HIPEs with enhanced mechanical strength using PVDBM‐b‐PEG‐emulsified CO2‐in‐water emulsions

Poly(vinyl acetate‐alt‐dibutyl maleate)‐block‐poly(ethylene glycol) (PVDBM‐b‐PEG) copolymers were synthesized via reversible addition–fragmentation chain transfer radical polymerization and used as emulsifiers to form stable CO₂‐in‐water high internal phase emulsions (C/W HIPEs). Then, highly interconnected cellular polyacrylamide (PAM) and poly(acrylamide‐co‐N‐hydroxymethyl acrylamide) [P(AM‐co‐HMAM)] poly‐HIPEs with enhanced mechanical strength were prepared based on the stable C/W HIPEs. The porous structures of the PAM poly‐HIPEs, as well as morphology and compressive modulus, could be influenced by the surfactant concentration and the length of the CO₂‐philic tails of the surfactants. PAM poly‐HIPEs with the smallest average pore diameter (11.12 ± 0.62 μm) and the highest compressive modulus (22.65 ± 0.10 MPa) could be obtained by using the short CO₂‐philic chains of the PVDBM‐b‐PEG surfactant at a high concentration (1.0 wt %). Moreover, with the copolymerization of N‐hydroxymethyl acrylamide (HMAM) comonomers with acrylamide, the compressive modulus of the obtained P(AM‐co‐HMAM) poly‐HIPEs was three times higher than that of PAM poly‐HIPEs. Both PAM and P(AM‐co‐HMAM) poly‐HIPEs were employed as scaffolds to guide H9c2 cardiac muscle cellular growth. Fluorescence images showed that a smaller average pore size and a narrower pore‐size distribution were helpful for cell growth and proliferation on these materials. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46346.     

Phototransparency and water vapor sorption properties of ABA‐type triblock copolymers derived from 6FDA‐TeMPD and poly(2‐methyl‐2‐adamantylmethacrylate)

The phototransparency and water vapor sorption properties of ABA‐type triblock copolymer membranes derived from 4,4‐(hexafluoroisopropylidene) diphthalic anhydride‐2,3,5,6‐tetramethyl‐1,4‐phenylenediamine (PI) and poly(2‐methyl‐2‐adamantylmethacrylate) (PMAdMA) were investigated, with focus on the effect of the adamantane component. The phototransparency of PMAdMA‐block‐PI‐block‐PMAdMA [Block(PI/PMAdMA)] was about 10–20% higher than that of poly(methyl methacrylate)‐block‐PI‐block‐Poly(methylmethacrylate) [Block(PI/PMMA)] because the high symmetric structure of adamantane inhibited photoabsorbance. The water vapor solubility of Block(PI/PMAdMA) decreased with increased PMAdMA because the PMAdMA had a hydrophobic property. Interestingly, in all relative‐pressure regions, Block(PI/PMAdMA) with the least PMAdMA content showed a higher solubility coefficient than PI because the high mobility of PMAdMA in Block(PI/PMAdMA) resulted in additional sorption sites in the PI segment. A comparison of Block(PI/PMAdMA) with Block(PI/PMMA) in terms of relative pressure at the beginning of clustering further revealed that cluster formation in Block(PI/PMAdMA) was inhibited compared with Block(PI/PMMA) because bulky structure of adamantane restricted the mobility of the polymer main chain. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43795.     

Dielectric property,electric breakdown,and discharged energy density of a poly(vinylidene fluoride‐co‐chlorotrifluoroethylene) copolymer with low temperature processing

Different thermal processing methods were used to fabricate the crystalline properties of poly(vinylidene fluoride‐co‐chlorotrifluoroethylene) [P(VDF‐co‐CTFE)] films. We observed that the crystallinity and crystal grain size of the various samples decreased with the quenching temperature. Compared to that of the annealed P(VDF‐co‐CTFE) sample, a higher dielectric constant of 13.9 at a frequency of 100 Hz was obtained in the film with liquid nitrogen quenching because the increasing small crystalline regions were susceptible to the excitation of external electric field. Meanwhile, the breakdown electric strength of the low‐temperature‐quenched film increased to 530 MV/m when the depth of shallow electronic energy level decreased, as depicted by Fröhlich collective electron approximated electric breakdown theory. Moreover, when we introduced the leakage current density curves, the effect of the space charges on the electric displacement was proven. As a result, the discharged energy density of the liquid‐nitrogen‐quenched P(VDF‐co‐CTFE) film was enhanced to 15.32 J/cm³ at an electric field of 530 MV/m; this provided an effective way in addition to chemical modification to achieve a high energy storage ability in this poly(vinylidene fluoride)‐based fluoropolymer. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42794.     

Synthesis and characterization of amphiphilic PMTFPS‐b‐PEO diblock copolymers

A series of new amphiphilic poly[methyl(3,3,3‐trifluoropropyl) siloxane]‐b‐poly(ethyleneoxide) (PMTFPS‐b‐PEO) diblock copolymers with different ratio of hydrophobic segment to hydrophilic segment were prepared by coupling reactions of end‐functional PMTFPS and PEO homopolymers. PMTFPS‐b‐PEO diblock copolymers synthesized were shown to be well defined and narrow molecular weight distributed by characterizations such as NMR, GPC, and FTIR. Additionally, the solution properties of these diblock copolymers were investigated using tensiometry and transmission electron microscopy. Interestingly, the critical micellization concentration increases with increasing length of hydrophobic chain. Transmission electron microscopy studies showed that PMTFPS‐b‐PEO diblock copolymers in water preferentially aggregated into vesicles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and ferroelectric investigations of poly(vinylidene fluoride‐co‐hexafluoropropylene)‐Mg(NO3)2 films

The free‐standing, flexible, and ferroelectric films of poly(vinylidenefluoride‐co‐hexafluoropropylene) [P(VDF‐HFP)] were prepared by spin coating method. The ferroelectric phase of the films was enhanced by adding magnesium nitrate Mg(NO₃)₂ in different wt % as the additive during the film fabrication. The effects on the structural, compositional, morphological, ferroelectric, dielectric, and leakage current behaviors of the films due to the addition of salt were analyzed. Based on the X‐ray diffraction (XRD) patterns and Fourier Transform Infrared (FTIR) spectra, it is confirmed that the addition of Mg(NO₃)₂ promotes the electroactive β phase that induces the ferroelectric property. The fiber‐like topography of the films exhibits a nodule‐like structure, and the roughness of the films increases by the addition of Mg(NO₃)₂. The ferroelectric studies show the higher polarization values for the composite films than that of the plain P(VDF‐HFP) film. The Piezo‐response force microscope images also confirm the domain switching behavior of the samples. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44008.     

Methyl methacrylate based copolymers and terpolymers: Preparation,identification, and plasticizing capability for a poly(methyl methacrylate) used in aviation

In this study, we first synthesized transparent poly(methyl methacrylate–maleic anhydride) [P(MMA–MAH)] and poly(methyl methacrylate–maleic anhydride–N‐2‐methyl‐4‐nitrophenyl maleimide) [P(MMA–MAH–MI)] via free‐radical polymerization at different monomer ratios. The synthesized polymers were characterized by titration, viscometric, spectroscopy, and thermal analyses. Higher contents of maleic anhydride (MAH) resulted in increases in the viscosity, glass‐transition temperature (T_g), and transparency. The synthesized polymers were then blended with a commercial‐grade poly(methyl methacrylate) (PMMA) used in aviation in the presence of CHCl₃. According to the free volume theory, the incorporation of 5 wt % P(MMA–MAH)s or P(MMA–MAH–MI)s into the commercial PMMA resulted in a plasticizing impact on this thermoplastic, which was confirmed by the decrease in the T_g values of the blends with almost the same transparency as the initial PMMA. In fact, the higher the content of MAH was, the lower the T_g of the blends was. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46603.     

Influence of LiClO4 on the thermal,mechanical, and morphological properties of P(DMS‐co‐EO)/ P(EPI‐co‐EO) blends

The UV‐vis absorption, thermal analysis, ionic conductivity, mechanical properties, and morphology of a blend of poly(dimethylsiloxane‐co‐ethylene oxide) [P(DMS‐co‐EO)] and poly(epichlorohydrin‐co‐ethylene oxide) [P(EPI‐co‐EO)] (P(DMS‐co‐EO)/P(EPI‐co‐EO) ratio of 15/85 wt %) with different concentrations of LiClO₄ were studied. The maximum ionic conductivity (σ = 1.2 × 10^?4 S cm^?1) for the blend was obtained in the presence of 6% wt LiClO₄. The crystalline phase of the blend disappeared with increasing salt concentration, whereas the glass transition temperature (T_g) progressively increased. UV‐vis absorption spectra for the blends with LiClO₄ showed a transparent polymer electrolyte in the visible region. The addition of lithium salt decreased the tensile strength and elongation at break and increased Young's modulus of the blends. Scanning electron microscopy showed separation of the phases between P(DMS‐co‐EO) and P(EPI‐co‐EO), and the presence of LiClO₄ made the blends more susceptible to cracking. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1230–1235, 2004     

Tailored ferroelectric responses and enhanced energy density in PVDF‐based homopolymer/terpolymer blends

Blend of polymers is an effective way to tailor the ferroelectric responses and improve the energy storage properties of polymers. In this work, the microstructure and dielectric responses of the blends of poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride‐trifluoroethylene‐chlorofluoroethylene) [P(VDF‐TrFE‐CFE)] have been studied. It is found that the addition of PVDF disturbs the crystallization process of P(VDF‐TrFE‐CFE), leading to lower crystallinity and smaller crystalline size. The aforementioned microstructure changes result in tailored ferroelectric responses. Dielectric responses show that the blend with 10 wt % PVDF achieves larger polarization response under high electric field (above 300 MV/m) due to the interfacial polarization. Because of the tailoring effect and the interfacial polarization, the blend with 10 wt % PVDF exhibits higher energy density and efficiency. Moreover, the breakdown strength (E_b) is also improved by adding a small amount of PVDF into the terpolymer. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40994.     

Synthesis of polyethylene‐graft‐poly(styrene‐co‐maleic anhydride) and its compatibilizing effects on polyethylene/starch blends

Low density polyethylene (LDPE) was reacted with benzoyl peroxide (BPO) and 2,2,6,6‐tetramethyl‐l‐piperidinyloxy (TEMPO) to prepare a latent macroinitiator, PE–TEMPO. Little polymer was synthesized when maleic anhydride (MAH) was bulk polymerized in the presence of the PE–TEMPO. However, addition of styrene accelerated the polymerization rate and PE‐grafted‐poly(styrene‐co‐maleic anhyride) [PE‐g‐P(ST‐co‐MAH)] was produced to a high yield. Chemical reaction between MAH units and hydroxyl groups of starch was nearly undetectable in the PE/PE‐g‐P(ST‐co‐MAH)/starch blend system, and the tensile properties of the blend were not enhanced significantly. However, addition of tetrabutyl titanate (TNBT) during the blending procedure improved the tensile properties significantly through an increased interfacial adhesion between the components in the blend system. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2434–2438, 2003     

Compatibilized blends of PVC/PA12 and PVC/PP containing poly(lauryl lactam‐block‐caprolactone)

Specially designed block copolymers have played a role as compatibilizing agents in the system of immiscible polymer blends. We applied lauryl lactam (LA)–caprolactone (CL) block copolymer [P(LA‐b‐CL)] as a compatibilizing agent for immiscible poly(vinyl chloride) (PVC) blends with various polymers. These blends possess high thermal performance and toughness. We investigated the effect of P(LA‐b‐CL) as a compatibilizing agent for immiscible PVC blends with poly(ω‐lauryl lactam) [polyamide 12 (PA12)]. We also described the invention of a new compatibilizing agent system involving P(LA‐b‐CL) for PVC/polypropylene (PP) blends. The mechanical and thermal properties of (1) PVC/PA12 blend compatibilized with P(LA‐b‐CL) and (2) PVC/PP blend compatibilized with P(LA‐b‐CL)/PA12/maleic anhydride–modified PP were both enhanced. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1983‐1992, 2004     

Methyl silsesquioxane/cyanate ester resin organic–inorganic hybrids with low dielectric constant

A kind of nonfunctional oligomeric silsesquioxane (SSQ), methyl silsesquioxane (Me‐SSQ), was used to modify cyanate ester (CE) resin in this article. First, Me‐SSQ was synthesized by the hydrolysis and condensation of methyltriethoxysilane. Then, a series of Me‐SSQ/CE hybrids containing 0, 1, 5, 10, and 20 wt % of Me‐SSQ were prepared. The effect of Me‐SSQ content on the reactivity, mechanical, dielectric, thermal, and hot/wet properties of materials was investigated. Fourier transform infrared spectroscopy was used to study the reactivity of hybrid CE resin systems, indicating that the addition of Me‐SSQ does not show significant effect on the conversion of CE. Mechanical and dielectric properties of the Me‐SSQ/CE hybrid materials were also studied. Impact strength of the Me‐SSQ/CE hybrids reaches its maximum value when Me‐SSQ content is 5 wt %. However, the flexural strength reaches the maximum value when Me‐SSQ content is 1 wt %. The Me‐SSQ/CE hybrid containing 20 wt % of Me‐SSQ shows a dielectric constant of 2.78, that is, much lower than the pure CE resin. At the same time, the dielectric loss of the Me‐SSQ/CE hybrids was slightly increased (tan δ < 0.006). Therefore, Me‐SSQ/CE hybrid is a promising candidate for high‐performance printed circuit board matrix materials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of water‐insoluble functional copolymers containing amide,amine, and carboxylic acid groups and their metal‐ion‐uptake properties

The crosslinked poly[N‐(3‐dimethylamino)propylmethacrylamide] [P(NDAPA)] and poly[N‐(3‐dimethylamino)propylmethacrylamide‐co‐acrylic acid] [P(NDAPA‐co‐AA)] were synthesized by radical polymerization. The resins were completely insoluble in water. The metal‐ion‐uptake properties were studied by a batch equilibrium procedure for the following metal ions: silver(I), copper(II), cadmium(II), zinc(II), lead(II), mercury(II), chromium(III), and aluminum(III). The P(NDAPA‐co‐AA) resin showed a lower metal‐ion affinity than P(NDAPA), except for Hg(II), which was retained at 71% at pH 2. At pH 5, the resin showed a higher affinity for Pb(II) (80%) and Cu(II) (60%), but its affinity was very low for Zn(II) and Cr(III). The polymer ligand–metal‐ion equilibrium was achieved during the first 20 min. By changing the pH, we found it possible to remove between 60 and 70% of Cd(II) and Zn(II) ions with (1M, 4M) HClO₄ and (1M, 4M) HNO₃. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5232–5239, 2006     

The changes of transesterification level in PET/PEN blends with the addition of PET–PEN copolymer

The extent of transesterification in poly(ethylene terephthalate) (PET)/poly(ethylene‐2,6‐naphthalate) (PEN) blends with the addition of PET–PEN copolymers was examined by DSC and ¹H‐NMR measurements to evaluate the factor affecting the reaction level at a given temperature and time. Both block (P(ET‐block‐EN)) and random (P(ET‐ran‐EN)) copolymers were used as the copolymers. At a given treatment temperature and time, the level was increased by the addition of P(ET‐block‐EN) into PET/PEN blends. On the other hand, a reverse change was observed when P(ET‐ran‐EN) was mixed with PET/PEN blends. During the treatment, an inhomogeneous phase of the blends changed into the homogeneous one; however, the change showed little effect on the reaction level. The effects of molecular weight on the reaction level were also examined. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009