Polar Polymer Matrix Research Articles

Proton transfer induced persistent triplet charge transfer phosphorescence in molecule-doped polymer systems

The intermolecular interactions between small molecules and the matrix in a highly polar environment could easily lead to non-radiative transitions, which significantly hampers the development of high-performance persistent room-temperature phosphorescence (pRTP) materials in such condition. Herein, we introduce a novel strategy that integrates consecutive proton transfer and photo-induced charge transfer to facilitate triplet charge transfer emission in highly polar polymer matrix. In particular, doping aza-arene guests including 1,10-phenanthroline (1,10-Phen), 2,9-dimethyl-1,10-phenanthroline (DM-Phen), and 7,8-benzoquinoline (7,8-BQ) into polyacrylic acid (PAA) resulted in superior pRTP properties compared to other polymer hosts. Spectroscopic investigations and theoretical calculations elucidate that this is attributed to the proton transfer and triplet charge transfer characteristics between the host and guest. Moreover, due to the rigid environment and space confinement provided by PAA, pRTP with the lifetime up to 841 ms is achieved. Capitalizing on the excellent water solubility of the doped PAA films, the inkjet printings have been executed, and showcasing the promising the potential applications of these pRTP materials in the field of information encryption.

Translating efficient fluorescence into persistent room-temperature phosphorescence by doping bipolar fluorophores into polar polymer matrix

In the doped phosphorescent films, highly polar PAA afforded the best phosphorescence performance mainly due to the strong host–guest polar–polar interaction.

Nanocomposites based on polyurethane and modified montmorillonite: thermodynamic approach to reinforcement

Nanocomposites based on thermoplastic polyurethane and montmorillonite (Mt) modified with oligourethaneammonium chloride were synthesized. The nanocomposites were obtained by the method solution exfoliation. The influence of the filler content on the thermodynamic of interactions, physical and mechanical properties, the structure and morphology of the created nanocomposites was investigated. The investigations have shown that the free energy of mixing the filler and the matrix during the formation of the nanocomposites decisively determines the physical and mechanical properties of the created nanocomposites. In case of thermodynamic compatibility between the matrix and the filler, dense surface layers of the matrix on the filler, high-quality polymer–filler contacts in the system are formed, which leads to the creation of nanocomposites with increased parameters of physical and mechanical properties. Mt modified with urethane-containing compounds can form strong hydrogen bonds with the polar polymer matrix and this allow to exfoliate the Mt up to the plates

Liquid Crystal Cellulose Nanocrystal/ Polyvinylpyrrolidone Pigments Engineered from Agro‐Waste Sugarcane Bagasse

AbstractBio‐inspired iridescent materials can possibly replace organic dyes and pigments, however, fabricating materials that resemble the appearance of absorbing pigments is challenging. Extracting cellulose nanocrystals (CNCs) from waste biomass is a sustainable practice in light of socio‐economic and environmental concerns. In an attempt, CNCs from sugarcane bagasse are isolated through acid hyrdolysis. Stable anisotropic dispersions of CNCs are doped with polyvinylpyrrolidone (PVP). Iridescent composite films are cast from these suspensions through evaporation–induced self‐assembly approach (EISA). The physicochemical properties of the films are studied at different loadings of PVP. These iridescent CNC/PVP composite films are then ball‐milled to produce iridescent red and blue tone color pigments. The morphology and optical properties of pigments are studied through Field emission scanning electron microscopy (FE‐SEM) and Hot‐stage Polarized Optical Microscopy (POM). These pigments are then re‐dispersed in a transparent polar polymer matrix to visually observe the color induced by them using solvent casting approach.

Tunable Van der Waals interfacial interaction for ultrahigh-damping rubber bends

High-damping rubber materials are of crucial significance for realizing high-performance green tire due to their contributions in noise and vibration reduction, auto-braking, and service life. However, the polarity difference and mismatched surface energy significantly reduce the interfacial interaction and compatibility between non-polar tread rubber materials and polar polymers. Herein, we fabricated a multi-functionalization high vinyl polybutadiene rubber (MFHVBR)/ethylene-vinyl acetate rubber (EVM) blend by simple mechanical blending. The incorporation of polar functional groups could increase the surface energy of MFHVBR, which was beneficial for regulating the interfacial compatibility and van der Waals interaction between non-polar rubber matrix and polar polymer matrix. A quantitative correspondence between van der Waals interaction and damping properties was determined. The optimized MFHVBR/EVM blends showed ultrahigh damping properties with an effective damping temperature range of −12.4–62.6 °C, which totally covered the service temperature of tires. The effective damping temperature range width of 75 °C was among the highest value of reported high-damping rubber materials. Meanwhile, the vulcanization efficiencies and physical mechanical properties were obviously improved. Collectively, the developed strategy herein and the proposed surface energy-performance relationship suggest a feasible pathway toward low-cost and high-performance green tire tread rubber materials.

Review of the past and recent developments in functionalization of graphene derivatives for reinforcement of polypropylene nanocomposites

AbstractGraphene has become the promising reinforcing candidate for improvement of polymer composites. However, graphene easily stacks into piles due to the presence of van der Waals forces between graphene layers and make it tremendously hard to be dispersed homogeneously in different polar polymer matrix. For years, some dispersion methods, such as chemical functionalization, melt mixing, solution mixing, in situ polymerization, to enhance the dispersion of nanofillers in polymer matrix have been demonstrated. Therefore, several functionalization methods of graphene, synthesis of composites approaches, characterizations techniques of graphene‐polypropylene composites are highlighted in this comprehensive review. This review also reveals that the addition of very low amount of nanofiller able to enhance the mechanical properties of composites considerably. With this review, a clear direction is beneficial for the researchers to solve the dispersion issues and to enhance interfacial adhesion to produce better mechanical properties of composites. The application of nanocomposite, an outlook of the challenges and different approaches that can practically useful to tackle important issues are also presented.

Open-cell P(VDF-TrFE)/MWCNT nanocomposite foams with local piezoelectric and conductive effects for passive airborne sound absorption

Open-cell nanocomposite foams of poly(vinylidene fluoride-co-trifluoroethylene) [P(VDF-TrFE)] and multi-walled carbon nanotubes (MWCNTs) were investigated for airborne sound absorption. When MWCNTs were well dispersed in the P(VDF-TrFE) matrix, the degree of crystallinity of the polar phase of the polymer was enhanced, and hence, the local piezoelectric effect and the electrical conductivity varied by nearly seven orders of magnitude dependent on the amount of MWCNT loading. The measurements in a standard acoustic tube showed that introduction of an appropriate amount of MWCNTs significantly enhanced the airborne sound absorption coefficient of P(VDF-TrFE) foam without poling, particularly in the lower and intermediate frequency range (below 2 kHz), which is attributed to the local piezoelectric effect in the polar polymer matrix and charge dissipation through the conductive MWCNT interfacing the polar phase. The experimental results and data analysis indicate that the open-cell nanocomposite foam with an optimal combination of local piezoelectric effect and electrical conductivity is promising for noise mitigation applications with enhanced passive airborne sound absorption.

Application of Single-Ion Conducting Gel Polymer Electrolytes in Magnesium Batteries

The development of polymer electrolytes for magnesium batteries has been hindered by difficulties related to achieving sufficient magnesium ion conduction and magnesium electrodeposition. The high charge density of the magnesium cation causes it to interact with both the polar polymer matrix and any counteranions, challenging ion transport. Solvents and salts that are known to be incompatible with the magnesium electrode have widely been used in prior reports to increase ionic conductivity. Herein we report the use of a single-ion conducting magnesium gel polymer electrolyte consisting of a poly(ethylene glycol) dimethacrylate (PEGDMA) crosslinker that is copolymerized with an anionic monomer and subsequently swelled in solvents compatible with magnesium metal. Sufficient magnesium ion conductivities (>10–4 S/cm at 25 °C) were able to be achieved with specific solvents and solvent mixtures. Constant potential holds were used to interrogate magnesium electrodeposition from these electrolytes. Small amounts...

Influence of zinc oxide in a polar polymer matrix

The creation of films constituted by semiconductor oxides of zinc oxide (ZnO) incorporated into a polar polymer matrix was proposed, looking for such films to be easy to apply, friendly to the environment and compatible with materials. Within the experimental process, the synthesis of styrene copolymers with a polar monomer (methyl methacrylate) was carried out through the suspension and emulsion polymerization processes.

Tri-layer nonwoven membrane with shutdown property and high robustness as a high-safety lithium ion battery separator

This paper presents a tri-layer membrane featured with double amido functionalized poly(ether ether ketone) outer layers and a poly(methyl methacrylate) interlayer and its application as a lithium ion battery separator. On one hand, the outer layers possess outstanding stability and endurance, which helps the tri-layer membrane to resist harsh conditions. On the other hand, the fusible interlayer can melt to block the pores of membrane once temperature is higher than 100 °C, which helps to prevent the lithium ion transmission between electrodes to terminate reactions in LIB. As a result, the tri-layer membrane exhibits remarkable features, including high maximum service temperature (350 °C), no area shrinkage at 150 °C, and wide shutdown temperature window (100–270 °C). The high stability and the shutdown property can avoid the thermal runaway of lithium ion battery, and greatly improve the safety. In addition, the wettability of the membrane is dramatically increased (contact angle= 0 °, vs. electrolyte) due to the strong interaction between polar polymer matrix and polar electrolyte, and the ionic conductivity of tri-layer membrane is 25.8% higher than the Celgard-2325 membrane at 30 °C (the 25 µm PP/PE/PP tri-layer membrane). The discharge capacity of LIB-NW-CA/P/CA is 3.7%, 7.6%, 9.7%, 12.2%, 13.5% and 54.3% higher than that of LIB-Celgard at 0.1 C, 0.2 C, 0.5 C, 1 C, 2 C and 5 C, respectively.

Enhancement of the dielectric response in polymer nanocomposites with low dielectric constant fillers.

In order to increase the dielectric constants of polymer-based dielectrics, composite approaches, in which inorganic fillers with much higher dielectric constants are added to the polar polymer matrix, have been investigated. However, high dielectric constant fillers cause high local electric fields in the polymer, resulting in a large reduction of the electric breakdown strength. We show that a significant increase in the dielectric constant can be achieved in polyetherimide nanocomposites with nanofillers whose dielectric constant can be similar to that of the matrix. The presence of nanofillers reduces the constraints on the dipole response to the applied electric field, thus enhancing the dielectric constant. Our results demonstrate that through nanostructure engineering, the dielectric constant of nanocomposites can be enhanced markedly without using high dielectric constant nanofillers.

A Single-Lithiun-Ion Conductor Coordinated Porous Pvfm-Peg Based Membrane and Plasticizer As Electrolyte for Lithium Ion Batteries

Polymer electrolyte comprised of lithium dissolved in polymer matrix has draw great attention due to its safety as well as processability, flexibility and lightweight. The dissociation of binary lithium salt in polar polymer matrix gives rise to so called bi-ionic conductors in which both cations and anions migrate as charge carriers. But unfortunatelly, a serious concentration polarization takes place in bi-ionic conductors due to the buildup of the anions at the electrode/electrolyte interface[1]. In order to solve the above problem, a single ion conductive polymer electrolyte has been proposed, in which the counter anions are tethered to the polymer backbone or immobilized in a matrix, eliminating polarization loss and enabling the passage of larger currents through the cells[2]. Until recently, single ion polymer electrolytes reported show low ambient temperature ionic conductivities (<10-6S·cm-1) due to the strong interaction between cations and their immobile matrixes[3]. A single-ion conductive hybrid electrolyte of porous PVFM-PEG based membrane and the optimized PC/EC (1/1, vol) mixed solvent as plasticizer was fabricated. The membrane and its electrolyte were characterized using scanning electron microscopy (SEM), stress-stain test, linear sweep voltammetry (LSV), ionic conductivity and lithium ion transference number measurement. The results indicate the combination of optimized PC/EC (1/1 in vol) plasticizer and porous PVFM-PEG based membranes[4] contributes to a considerable enhancement of room-temperature conductivity to 1.59×10-4S/cm. At the same time, lithium ion transference number of hybrid electrolyte based on the porous PVFM-PEG electrolyte membranes increased to 0.76. The assembled cells from the hybrid electrolyte also show wide electrochemical stability window and excellent cyclability.Reference [1] Bouchet R, Maria S, Meziane R, et al. Single-ion BAB triblock copolymers as highly efficient electrolytes for lithium-metal batteries[J]. Nature materials, 2013, 12(5): 452-457. [2] Sinha K, Wang W, Winey K I, et al. Dynamic Patterning in PEO-Based Single Ion Conductors for Li Ion Batteries[J]. Macromolecules, 2012, 45(10): 4354-4362. [3] Kobayashi N, Uchiyama M, Tsuchida E. Poly [lithium methacrylate-co-oligo (oxyethylene) methacrylate] as a solid electrolyte with high ionic conductivity[J]. Solid State Ionics, 1985, 17(4): 307-311. [4] Fang Lian, Hong-yan Guan, Yan Wen, Xiao-rong Pan, Polyvinyl formal based single-ion conductor membranes as polymer electrolyte for lithium ion batteries, Journal of membrane science 2014, 469, 67-72

Photoinduced electron and energy transfer within a pyrene-perylenediimide dyad embedded in polymer matrixes

To investigate the effects of polymer matrixes on the competition between energy and electron transfer, a covalently linked pyrene-perylenediimide dyad (PDI-PY) has been prepared. Competition between the energy and electron transfer from PY to PDI within PDI-PY is revealed by steady state absorption and fluorescence spectra, as well as time resolved fluorescence spectra. Polar solvents accelerate the electron transfer while non-polar solvents favor the energy transfer. When PDI-PY is embedded in a non-polar polymer matrix, the energy transfer becomes the only photoinduced process between PY and PDI, whereas the electron transfer is almost completely hindered. In a polar polymer matrix, the energy transfer is still a dominating process, but with a remarkably decreased efficiency. The electron transfer in a polar polymer matrix is much slower and less efficient with respect to that in solutions, but faster and more efficient than that in non-polar polymer matrixes. This result suggests that polymer matrixes are ideal environment for constructing light harvesting systems, which in some case can reduce the disturbance from electron transfer.

Gas-chromatographic studies of the sorption thermodynamics of adamantanes on a carbon adsorbent modified with polyethylene glycol with β-cyclodextrin additives

The thermodynamic characteristics of sorption of adamantane and its derivatives on a mixed stationary phase consisting of a graphite-like solid substrate, polyethylene glycol, and β-cyclodextrin (βCD) were determined by gas chromatography. The introduction of β-CD additives to a polar polymer matrix was shown to considerably decrease the chromatographic retention of the sorbates, which is evidence of the macrocyclic effect. The presence of β-CD molecules was found to increase the selective properties of the mixed sorbent with respect to the structural isomers of adamantanes.

Controlling the Interaction of Light with Polymer Semiconductors

In this study, a generally applicable strategy is described to manipulate the optical properties of a wide range of polymer semiconductors in the solid state. Blending these materials with a non-conjugated, polar polymer matrix is found to be the processing key to a drastic change and red-shift of the absorption characteristics.

Comparative study about preparation of poly(lactide)/Organophilic montmorillonites nanocomposites through melt blending or ring opening polymerization methods

AbstractThe present article is focused onto the study of nanostructure, thermal and mechanical properties of nanocomposites composed of poly(lactide) (PLA), and a constant amount of montmorillonite (MMT) clays (3 wt %). Properly modified organoclays with easily available commercial compounds were prepared in order to allow the homogeneous dispersion of the hydrophilic clays in the polar polymer matrix; in particular, 2‐hydroxyethyl‐trimethylammonium (choline), polyethyleneoxide(15)‐(hydrogenated tallow)‐ammonium, and oligochitosan salts were used as surfactants as their structure can match the requirements of a biocompatible material. These organically modified MMTs (OMMTs) were used for preparing composites by melt blending or by in situ ring opening polymerization (using the clay surfactant as polymerization initiator) followed by melt dispersion into a PLA matrix. Structural, morphological, and thermo‐mechanical properties of the products are compared in order to assess advantages and disadvantages of the two different preparation routes. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

LDH as Nanofiller: Organic Modification and Dispersion in Polymers

AbstractSummary: Layered double hydroxide (LDH) is a relatively new class of layered crystalline clay materials to be used as nanofiller in various polymer matrices. We report here the organic modification of LDH by anionic surfactants having different sizes and functionalities. Subsequently, their dispersion in polymer is discussed and finally the characteristics of the polymer/LDH nanocomposites are investigated. LDH has been modified using regeneration method, which shows that irrespective of size and functionality of the anionic surfactant, organic modification can be carried out efficiently. However, it has been observed that alkyl sulfonate are more efficiently intercalated within LDH layers than other surfactants giving well defined crystal structure of the modified LDH. These modified LDH, when dispersed in polymers like maleic anhydride grafted polyethylene shows that not only the size of the surfactant, but also the functionality of the surfactant influences their dispersion in a non polar polymer matrix.

Functionalized Picolinium Quinodimethane Chromophores for Electro-Optics: Synthesis, Aggregation Behavior, and Nonlinear Optical Properties

A new series of functionalized and thermally stable zwitterionic picolinium (dicyano)esterquinodimethane (PeQDM) chromophores have been synthesized in one step from 7,8-di(methoxycarbonyl)-7,8-dicyanoquinodimethane (DMCQ) and various picolinium salts in methanol in nearly 50% overall yields. Hyper-Rayleigh scattering (HRS) measurements at 1.07 μm show very large near-resonant molecular first hyperpolarizabilities β up to 1800 × 10−30 esu, despite the fact that, compared to previously studied zwitterionic NLO chromophores, one of the strong CN acceptor groups is substituted by a weaker ester group to allow for further functionalization. The ester functionality can be further utilized for attachment of solubility-imparting groups, cross-linkers, and reactive groups for grafting the chromophore onto a polymer. To optimize the electro-optic (EO) activity in the polymer matrix, the aggregation behavior of the PeQDM chromophores is studied. X-ray crystallographic analysis confirms the charge-separated ground-state of PeQDM and reveals the formation of a face-to-face, antiparallel H-aggregation with a large slip angle (θ = 64.5°) between the chromophores. In a less polar polymer matrix, PeQDM chromophores can form H- and/or J-aggregates and only J-aggregates could contribute to the EO activity if the monomeric chromophores released during the thermally induced J−H transformation could be captured and effectively poled. In a more polar polymer host, chromophores are well dissolved as monomers and effectively poled. A large and stable EO activity (r33 = 110 pm/V) has been achieved with a polyethersulfone film doped with 5 wt % of N-benzyl picolinium (dicyano)esterquinodimethane (PeQDM-Ben).

Medium Effect of Polymer Matrices on Spectral Properties of 4‐Aminophthalimide and 4‐Dimethylaminophthalimide

Absorption and fluorescence spectra of 4‐aminophthalimide (API) and 4‐dimethylaminophthalimide (DAPI) were taken in solution of chloroform, methanol and water and polymer matrices as polystyrene (PS), poly(methyl methacrylate), (PMMA), polyvinylchloride (PVC) and polyvinylalcohol (PVA). The absorption spectra were dependent on the medium slightly; the longest wavelength band being around 350 nm for API and 390 nm for DAPI. Contrary to it, fluorescence of both probes is strongly influenced by polarity of the medium. The fluorescence in polar methanol or water is strongly bathochromically shifted from around 410 nm in cyclohexane up to 550 nm for API and 570 nm for DAPI in water. The quantum yield of fluorescence in polar solvents is low and it exhibits a short lifetime (under 1 ns for both API and DAPI). In polar solvents, both probes exhibit a large Stoke's shift up to 8,000 cm−1. In polymer matrices both probes exhibit intense fluorescence as compare to anthracene with a lifetime longer than 10 ns and with a Stokes shift around 4,000 cm−1. The less polar polymer matrix is polystyrene. In contrast, no strong medium effect is observed in polar PVA as compared with polar solvents. The reasons for different behavior of molecular probes in polar solvents of low viscosity and in polymer matrices are discussed.

Layered Silicate Reinforced Polymer Nanocomposites: Development and Applications

This review provides a rationale for polymer nanocomposites, emphasizing layered (smectic) silicate reinforcements, particularly montmorillonite clay with various surfactant treatments. Considerable attention is given to processing techniques for synthesizing such nanocomposites via compounding in the melt. While briefly covering structural characterization, it focuses on physico‐mechanical properties, using examples of nylon as a polar polymer matrix and polypropylene, the continuous phase in a thermoplastic vulcanizate (TPV), as a non‐polar polymer matrix. Both polar and non‐polar rubber components are considered for the TPV. Thus, the thermodynamic compatibility between a surfactant‐treated clay and the polymer matrix as well as the partitioning of the clay reinforcement in a two‐phase heterogeneous polymer blend are addressed. Finally, functional performance is reviewed, with an emphasis on automotive applications.