Low Polarity Polymers Research Articles

Volatile profiles of Murcott and Ponkan mandarins obtained by stir bar sorptive extraction technique and their contributions to the fruit aroma.

Citrus species have undergone immense diversification ever since their ancestral origin. Ponkan and Murcott are two mandarin varieties widely consumed in Brazil and their aroma producing active compounds have not yet been extensively investigated. The present study analyzed the volatile constituents of the Ponkan and Murcott varieties employing the stir bar sorptive extraction (SBSE) technique and gas chromatography-mass spectrometry (GC-MS) analysis for the first time. Extraction was performed using the two phases of Twister bar, polydimethyl siloxane (PDMS), and ethylene glycol (EG) silicone in immersion and headspace modes. Among the detected 62 compounds comprising alcohols, aldehydes, esters, terpenes, and others identified, 55 and 37 compounds in the Ponkan and Murcott variety were determined, respectively, from both immersion and headspace modes using the two phases of Twister bar. From the odor active values, the Ponkan was characterized with the domination of compounds such as hexanal, decanal, nonanal, (E)-2-hexanal, ethyl hexanoate, d-limonene, linalool, and geraniol. Similarly, the Murcott variety was characterized with predominant compounds, namely, nonanal, octanal, hexanal, (E)-2-hexanal, ethyl hexanoate, d-limonene, and linalool. The profile of volatile compounds was found to be unique in both the varieties studied, and SBSE technique with GC-MS analysis favored the characterization of their respective profile due to the high amount of phase in the Twister bars, when compared to similar techniques, like solid phase microextraction. The PDMS Twister bar showed better capacity of adsorption of volatile compounds, since it is a relatively low-polarity polymer, which discriminates less analytes with different structures and polarities sampled from complex matrices, such as fruits juice.

Bioinspired Organic Porous Coupling Agent for Enhancement of Nanoparticle Dispersion and Interfacial Strength.

Composite materials have significantly advanced with the integration of inorganic nanoparticles as fillers in polymers. Achieving fine dispersion of these nanoparticles within the composites, however, remains a challenge. This study presents a novel solution inspired by the natural structure of Xanthium. We have developed a polymer of intrinsic microporosity (PIM)-based porous coupling agent, named PCA. PCA's rigid backbone structure enhances interfacial interactions through a unique intermolecular interlocking mechanism. This approach notably improves the dispersion of SiO2 nanoparticles in various organic solvents and low-polarity polymers. Significantly, PCA-modified SiO2 nanoparticles embedded in polyisoprene rubber showed enhanced mechanical properties. The Young's modulus increases to 30.7 MPa, compared to 5.4 MPa in hexadecyltrimethoxysilane-modified nanoparticles. Further analysis shows that PCA-modified composites not only become stiffer but also gain strength and ductility. This research demonstrates a novel biomimetic strategy for enhancing interfacial interactions in composites, potentially leading to stronger, more versatile composite materials.

Novel Temporary Bonding Film Adapted to Xenon Flash Lamp De-bonding System for FOWLP Application

Temporary bonding film (TBF) is one of the key materials for assembly process of fan out wafer level package (FOWLP). In this paper, we have proposed a novel TBF and xenon flash lamp de-bonding system. The TBF was mainly composed of cross-linkable and low-polarity polymers to meet the various requirement for not only easy peeling-off after assembly but also stability against thermal and chemical environment exposed in FOWLP process. In order to evaluate applicability of the developed material, die-first/face up test wafer was assembled. As a result, it was found that the TBF has high stability and can be de-bonded by xenon light irradiation. In addition, the die shift through assembly process was within the estimated range. These results offer that the developed TBF is practically applicable for FOWLP assembly process.

Effects of Polarity of Polymers on Conformation and Lubricating Film Formation of Adsorbed Films

The conformations and lubricating film formation ability of adsorbed films on metal surfaces formed by poly(alkyl methacrylate) (PAMA) homopolymers with different polarities from nonpolar lubricant oil were investigated. It was found that as the polarity of the polymers became higher, the chains in the adsorbed films adsorbed more loosely to the surfaces (i.e., they formed more loops and tails). The loosely adsorbed chains temporarily trapped free polymer chains flowing into the gap between sliding surfaces, resulting in a much thicker lubricating film. Thus, the sliding surfaces were better protected from wear caused by direct contact. On the other hand, flattened chains occupying in the adsorbed film formed by low polarity-polymers could not trap free polymer chains, resulting in a thinner lubricating film.

Multi-component Polymer Systems Comprising Wood as Bio-based Component and Thermoplastic Polymer Matrices – An Overview

The production of wood-based polymer composites has gained increasing interest in recent years, especially regarding sustainability issues, aiming at the recovery, reuse, and up-cycling of by-products from natural resources exploitation, as well as plastics. Due to their reduced cost, low density, and availability, wood components (fibers, flour) are attractive fillers for thermoplastic polymer matrices used in multi-component systems. Performance of wood-based thermoplastic materials mainly depends on the type and strength of interactions at the polymer-wood interface. Different low polarity polymers (high/low density polyethylene, polypropylene, polyvinylchloride) can be successfully used as matrices in such formulations. Various methods may be applied in order to obtain specified performance attributes of wood-based composites. Addition of appropriate compatibilizing agents, chemical and/or physical modification of the filler in order to improve its compatibility towards the matrix, or a judicious combination of these approaches may be employed. This paper briefly reviews some recent literature data, as well as research results by the authors, aiming at a comparative assessment of the materials properties (structure, thermal, mechanical and water sorption behavior) in correlation with the nature and type of components, processing, recycling options, and environmental impact.

Linear Viscoelasticity and Dielectric Spectroscopy of Ionomer/Plasticizer Mixtures: A Transition from Ionomer to Polyelectrolyte

For ionomers, unfavorable interaction between highly polar ion pairs and the low polarity polymer medium leads to ion aggregation. In contrast, for polyelectrolytes, the counterions prefer solvation in the polar medium to leave the chain charged and accordingly stretched due to the charge repulsion. In this study, linear viscoelastic and dielectric properties of mixtures of two ionomers with high dielectric constant low volatility plasticizers were examined. The ionomer chains having bulky side chains are not entangled. Upon increasing the plasticizer content, the terminal relaxation is significantly accelerated due to two effects: (1) a plasticizing effect lowering the Tg and (2) a higher dielectric constant that softens the ionic interactions, leading to ionic dissociation into isolated pairs that further boosts the static dielectric constant at low frequency/long time. A model incorporating these two mechanisms and utilizing a dielectric constant eC, after the nonionic segmental α relaxation as the rel...

A cement interface enhancer and its action mechanism

A cement interface enhancer (CIE) to improve the well cementing quality for fresh water-based drilling fluid was prepared and its action mechanism was studied. The composition and the proper dosage of CIE were studied with mud cake strength test and steel plate immersion test. CIE contained inorganic mineral fibers such as calcium silicate, silica nanoparticles, and low polarity polymers; the proper proportion was about 1.8:1.2:1. The cementing strength simulation experiments showed that the cementing strengths of the interfaces between the cement and the wellbore casing (the first interface), and the cement and the borehole wall (the second interface) were increased by three and four times, respectively, when 0.8 % (weight) of CIE was added into the drilling fluid. This was due to the support effect, inductive effect, and electrostatic repulsion of CIE, and the bonding of cement with mud cake was improved. The application of CIE in Daqing Oilfield showed that the cementing perfection rate could be increased by 30 % that indicated CIE could improve the well cementing quality effectively.

P.64: WITHDRAWN: P.65: The Effect of Surface Polarity of Gate Dielectric Buffer Layer on Operational Stability in Organic Thin Film Transistors

AbstractWe studied the effect of surface polarity of gate dielectric buffer layer on operational stability in organic thin film transistors (OTFTs). By employing four types of polymers with different polarity, we found out the operational stability of OTFTs can be improved with low‐polarity polymer gate dielectric buffer layer. With low‐polarity polymers, the devices showed good operational stability with longer relaxation time than 106 sec. Also, threshold voltage of the devices shifted less than 2 V under high gate bias stress of 3 MV/cm for two hours. Good stability may be resulted from low surface trap density as well as good grain interconnection of pentacene on low‐polarity polymer.

Photo-fries rearrangements of 1-naphthyl esters in the glassy and melted states of poly(vinyl acetate). Comparisons with reactions in less polar polymers and low-viscosity solvents.

The photo-Fries and associated photoreactions of four 1-naphthyl acylates have been examined in two types of poly(vinyl acetate) (PVAc) films above and below their glass transition temperatures, Tg. Because of the 'templating' effect of the esters on their reaction cavities, especially below Tg, the distributions of photo-Fries products, as mandated by the intermediate acyl/1-naphthyloxyl singlet radical pairs, are determined largely by the initial conformations of the guest molecules. Even above Tg, at 50 degrees C, where segmental chain motions of PVAc are relatively rapid, the influence of the cages in directing product formation is apparent. The radical-pair recombination rates for formation of the keto precursor of 2-(2-phenylpropanoyl)-1-naphthol upon irradiation of 1-naphthyl 2-phenylpropanoate in PVAc are reduced drastically as the temperature is lowered from above to below Tg. Comparison of results in PVAc with those in low-viscosity solvents (ethyl acetate and hexane) and low-polarity polymer films (polyethylene and polypropylene) indicate that interactions between the radicals produced from irradiation of 1 and the acetate pendant groups of PVAc, as well as the nature of its chain motions above and below Tg, influence enormously the course of the photo-Fries rearrangements.

Investigation of intermolecular interactions in solution polymer-organic dye by method electronic spectroscopy

It has been shown that specific electrostatic interactions between charges of ion dyes and functional groups of polymer play main role in the cause of polar coulored matrices. These interaction prevent by formation tight ion pairs of dyes and their associates. Therefore, such matrices have practically the same electronic spectra as liquid solution of dyes. Electrostatic interactions between dye counterions dominate in low polarity polymer matrices. Process of formation tight ions pair is became easier. Such pairs cause quenching of the fluorescence and distortion of electronic spectra by comparison with liquids.

Production of hollow polymer particles by suspension polymerizations for divinylbenzene/toluene droplets dissolving various polymers

Suspension polymerizations for divinylbenzene/toluene droplets dissolving different kinds of methacrylate and acrylate homopolymers were carried out. Hollow polymer particles were produced not with high polarity polymers but with low polarity polymers. The results indicate that the preferential adsorption of the homopolymers having high polarity at the interface of the droplets depresses the formation of the hollow structure. A minimum polymer concentration was necessary to produce hollow particles.

Dual-phase polymer electrolyte prepared from polar and non-polar latices

A new type of polymer electrolyte, dual-phase polymer electrolyte (DPE), for lithium battery application has been designed. DPE is composed of interpenetrating networks of ionically conductive phase and supporting phase, where the conductive phase consists of high-polarity polymer/liquid electrolyte gel and the supporting phase consists of low-polarity polymer. DPE is prepared from a mixture of high-polarity and low-polarity polymer latices by a novel process. Micro-elementary analysis confirmed that DPE fabricated in this process has a dual-phase structure as designed. The conductivity was enhanced by increasing the liquid electrolyte content while the supporting phase maintains mechanical strength, and the conductivity on the order of 1 mS/cm was consequently attained. The tensile mechanical strength reached 3 MPa by improving the preparation process. The conductive and mechanical properties are discussed in relation to the dual-phase micro-structure.

Properties of decalin as a solvent in thermal field-flow fractionation

Cis-trans-decahydronaphthalene (67.85% trans+ 32.15% cis, here briefly referred to ascis-trans-decalin) as a possible solvent for thermal field-flow fractionation is proposed. Different features such as solvent properties with respect to low polarity polymers, availability of basic physicochemical data (viscosity and thermal conductivity in a convenient temperature range), low toxicity and low cost are emphasized. Retention data over a wide range of cold wall temperatures and thermal gradients were collected. Thev correction factor and λ retention data were determined for polystyrene samples over a relative molecular mass range of 11,300–3,950,000 g mol−1. From these data, selectivity values were determined and compared to the commonly found values for polystyrene in different solvent systems. The average value of −0.6 found here forcis-trans-decalin falls in the optimum selectivity solvent-domain.Cis-trans-decalin is thus fully proven as an optimum solvent for ThFFF.

Examination of Vapor Sorption by Fullerene, Fullerene-Coated Surface Acoustic Wave Sensors, Graphite, and Low-Polarity Polymers Using Linear Solvation Energy Relationships

The sorption of vapors by fullerene is compared with the sorption of vapors by an assembled fullerene thin film on a surface acoustic wave vapor sensor. A linear solvation energy relationship derived for solid fullerene at 298 K was used to calculate gas/solid partition coefficients for the same vapors as those examined using the vapor sensor. This relationship correctly predicted the relative vapor sensitivities observed with the vapor sensor. A new linear solvation energy relationship for vapor adsorption by graphite at 298 K has been determined, and solid fullerene and solid graphite are found to be quite similar in their vapor sorption properties. Comparisons have also been made with linear organic and inorganic polymers, including poly(isobutylene), poly(epichorophydrin), OV25, and OV202. In all cases, sorption is driven primarily by dispersion interactions. The assembled fullerene material is generally similar in vapor selectivity to the other nonpolar sorbent materials considered but yields less sensitive vapor sensors than linear organic polymers. 39 refs., 2 figs., 2 tabs.