Synthesis Of Polymeric Materials Research Articles

Role of Self-Polarization in a Single-Step Controlled Synthesis of Linear and Branched Polymer Nanoparticles

In this work, the synthesis of linear (with high aspect ratio) and branched polymer nanoparticles (Nps) via single-step nanoassembly in a semi-microfluidic platform is reported. The shape-controlled synthesis of polymeric material at nanometer scale level remains challenging due to their amorphous or semicrystalline nature. A key to success of this strategy to obtain the compact linear and branched shape of polymer Nps in a single-step is the use of appropriate concentration of polyelectrolyte molecules in the aqueous phase, and microfluidic technique due to their advantages for providing precise mixing, efficient volume transfer, emulsification, and very homogeneous reaction conditions. The in situ nanoassembly of growing polymer Nps at critical stages during the ongoing polymerization obviously depends on the number of electrical charges supplied by accessible polyelectrolyte that is explained here in detail. The impacts of the different parameters such as concentration of polyelectrolytes, their chain-lengths, volume ratios, flow rate ratios, and so forth, have been systematically investigated in order to obtain linear and branched polymer nanoparticles.

Improving the Charge Conductance of Elemental Sulfur via Tandem Inverse Vulcanization and Electropolymerization.

The synthesis of polymeric materials using elemental sulfur (S8) as the chemical feedstock has recently been developed using a process termed inverse vulcanization. The preparation of chemically stable sulfur copolymers was previously prepared by the inverse vulcanization of S8 and 1,3-diisopropenylbenzene (DIB); however, the development of synthetic methods to introduce new chemical functionality into this novel class of polymers remains an important challenge. In this report the introduction of polythiophene segments into poly(sulfur-random-1,3-diisopropenylbenzene) is achieved by the inverse vulcanization of S8 with a styrenic functional 3,4-propylenedioxythiophene (ProDOT-Sty) and DIB, followed by electropolymerization of ProDOT side chains. This methodology demonstrates for the first time a facile approach to introduce new functionality into sulfur and high sulfur content polymers, while specifically enhancing the charge conductivity of these intrinsically highly resistive materials.

“Click”-Inspired Chemistry in Macromolecular Science: Matching Recent Progress and User Expectations

This year, it has been a decade that the concept of “click” chemistry was pioneered in polymer and material science by the exploration of the synthetic scope of copper-catalyzed azide/alkyne cycloaddition (CuAAC), the “click” benchmark. The impact on the endeavors of polymer chemists has been substantial because the power of this concept, featuring modularity, orthogonality, and versatility for the design and synthesis of polymeric materials, was recognized very soon in macromolecular research groups worldwide. After this first burst of research activity, challenging the boundaries of CuAAC in terms of attainable polymer constructs, ongoing method development, and implementation, in response to the need for metal-free alternatives, resulted in a valuable toolbox of “click”-inspired conjugation methods. Because of the large diversity of employable reactions, applied in various polymeric systems, the first-time or occasional “click” user will be confronted with a burden of choice. Therefore, the principal aim of this Perspective is to clearly denote the recent progress of “click”-inspired chemistry in macromolecular science by detailed conceptual analysis and to provide some selection procedures, allowing potential users to readily match their expectations of “click” chemistry to the state-of-the-art. Consequently, first-time or occasional users should be able to identify and select the most appropriate “click”-inspired reaction for their purposes and eventually contribute to the next generations of advanced polymeric materials.

Polymer Thermosets from Multifunctional Polyester Resins Based on Renewable Monomers

The use of monomers based on natural materials as a future supply of raw materials has gained more interest in the last decade. Sources ranging from wood to plant oils and algae are exploited as alternatives to traditional fossil‐based resources for the synthesis of polymeric materials. The use of these raw materials is not only of interest because of its abundance, but also in terms of price, durability, and/or biodegradability. In the present study, a series of resins utilizing a monomer derived from birch bark is prepared. The thermoset resins are formed by reacting an epoxy‐functional ω‐hydroxy fatty acid with methacrylate monomers using enzyme catalysis to form multifunctional resins via a one‐pot synthesis. The derived oligomers are crosslinked through different polymerization routes to produce thermosets with different properties and/or functionalities. This approach allows natural‐based resins with tuned functionalities and mechanical and thermal properties to be obtained. image

Engineering the surface chemistry of porous polymers by click chemistry and evaluating the interface properties by Raman spectroscopy and electrochromatography

This manuscript is intended to summarize strategies developed to chemically functionalize the surface of porous polymeric materials using the so‐called click reactions with the general aim of developing chromatographic stationary phases with well‐defined interfacial characteristics. The preparation pathway starts with the synthesis of polymeric materials with micrometre‐sized channel‐like pores providing enhanced permeability and fast mass transfer. Such monolithic structure is obtained by solvent‐induced phase separation occurring in the course of the free radical polymerization of functional monomers and crosslinkers mixture. The presence of functional groups on the monolith surface allows its further functionalization through click chemistry. Herein, implementation of Huisgen, thiol‐ene, thiol‐yne and diels–alder click‐type reactions is discussed for the grafting of molecular and oligomeric selectors. This work undoubtedly highlights click‐surface chemistry as a powerful surface modification strategy for tuning, at the molecular level, the chemical nature of pores surface. Copyright © 2014 John Wiley & Sons, Ltd.

Solvothermal synthesis of polyazomethine microspheres by Pickering emulsion templates and their transformation into complex microtubes and anisotropic hollow spheres enabled by dynamic imine chemistry

Dynamic covalent chemistry has attracted much attention in recent decades. Here we report a facile one-pot solvothermal synthesis of anisotropic polyazomethine particles using Pickering emulsions formed in situ as templates. An unexpected morphological transformation from nanoparticles to anisotropic particles and finally to complex anisotropic yolk-shell structures was observed. The underlying mechanism is a controlled chemical etching process enabled by the dynamic imine bonding and the inhomogeneous nature of the resulting anisotropic particles. The generalizability of this process was further proved by fine tuning the initial solvent composition, through which an interesting morphological transformation from hollow spheres to worm-like tubes and finally to microtubes with a smooth surface was observed, thus providing a novel template-free strategy for the synthesis of polymeric materials with complex hollow interiors, which has rarely been reported in polymeric systems. Complex polymeric hollow spheres were made easy. We reported a facile one-pot solvothermal synthesis of anisotropic polyazomethine particles using the in-situ formed Pickering emulsion as templates. Taking advantage of the dynamic nature of imine bonding and the inhomogeneous nature of the particles, these anisotropic particles can further hollow into and result in complex anisotropic yolk-shell and anisotropic hollow spheres, which were heretofore rarely reported in polymeric systems.

Polymeric Materials Synthesis by Oxidative Polymerization of Triacylglycerides and Derivatives

Polymeric Materials Synthesis by Oxidative Polymerization of Triacylglycerides and Derivatives

Novel aliphatic polyesters from an oleic acid based monomer. Synthesis, epoxidation, cross-linking and biodegradation

The synthesis of polymeric materials based on monomers from renewable feedstocks is a steadily growing field. New aliphatic polyesters derived from the 1,18-(Z)-octadec-9-enedioic acid (D18:1), a high oleic sunflower oil fatty acid derivative, and aliphatic diols of different molecular weight (from 1,3-propanediol to 1,12-dodecanediol) have been synthesized and characterized. The polymerization was undertaken by direct bulk polycondensation of a diacid with a diol, with or without a metal catalyst, leading to viscous liquid to solid semi-crystalline polyesters at room temperature, depending on the diol type. The molecular weights of polyesters ranged between 7000 and 20,000gmol−1. The main attractive aspects of these polyesters are the renewable biomass origin of the diacid and the presence of double bonds on the polymer backbone (oleic acid derivative) allowing subsequent chemical modifications. The epoxidation of these double bonds was undertaken on the macromolecular chains to induce the photochemical cross-linking of the epoxide functions. Transparent and homogeneous cross-linked films were made by photo-polymerization of the epoxy units with less than 5% of extractible products. Enzymatic degradation of these polyesters (cross-linked) was poor over 8weeks.

Preparation and Properties of Polyurethane Heat Insulating Building Materials Based on Lignin

The synthesis of polymer materials from renewable biomass resources has attracted lots of attention. In this study, lignin based polyurethane heat insulating building materials were prepared from isocyanate and lignin polyol. Lignin was modified by polyethylene glycol and glycerol with 0.6% acid at 120°C to obtain lignin polyol containing reactive hydroxyl groups, and then polyurethane foams were prepared by the reaction between the above lignin polyol and isocyanate. Hydroxyl value of lignin polyol, gel time, apparent activation energy for polymerization, impact strength and thermal conductivity of lignin based polyurethane were investigated. The results showed that: (1) hydroxyl value achieved 397.0 mgKOH/g at temperature 120°C; (2) the apparent activation energy for lignin based polyurethane polymerization was 34.12 kJ/mol; (3) compressive strength reached 291 kPa with lignin polyol content 30%; (4) thermal conductivity was 0.02517 W/mK when lignin polyol dosage was 30%. It was detected that lignin could be used to prepare polyurethane heat insulating building materials in replacement of petroleum polyols.

Curing Behavior Characterization of Phenolic Resin Derived from Starch

With increasing concern about the protection of the environment and the shortage of petroleum resources, the synthesis of polymer materials from renewable biomass resources has attracted a lot of attention. Starch based phenolic resin was prepared via hydrolyzation and condensation of starch at different temperatures from 120 °C to 200 °C. Gel time, apparent activation energies for curing reaction, impact strength, crystal structure and thermal resistance were studied. The results showed that: (1) the apparent activation energy for curing reaction was 19.8 kJ/mol; (2) crystal structure changed as a function of starch hydrolysis; (3) electron microscopy showed the disappearance of starch during the hydrolyzation; (4) the impact strength of starch based phenolic resin was 741 J/m2 and residual mass at 600 °C was 40%. These results were compared with those of formaldehyde based phenolic resin, and it was detected that starch could be used to prepare phenolic resin in replacement of formaldehyde

Sustainable Polymers Derived From Naturally Occurring Materials

Nearly 95% of monomers or chemical intermediates used today are based on fossilized carbon such as coal and petroleum. This has resulted in a high rate of depletion of fossilized reserves, continuous escalation in petroleum prices, environmental impact with the increase in emission of greenhouse gases, and accumulation of non-biodegradable waste on earth. Current global main challenges are moving towards green sources - need for vast new and sustainable material resources; supplement, reuse and replace petroleum based polymeric materials; biodegradability of materials to prevent build up of waste; toxicity associated with the preparation, usage and environmental safety. Recent investigations are therefore, focused on procuring materials from the plant resources, agricultural waste and their utility in synthesis of polymeric materials. Amongst the polymers derived from natural resources poly(lactic acid) is a leading candidate. Commercial quantities of natural oil-based polyols such as castor, soya bean oil have been available over the past several years and currently used for synthesis of polyesters, polyurethanes etc, but today many other natural materials are also being investigated. It should be possible to produce sustainable polymers commercially and economically.

Controlled radical polymerization: Prospects for application for industrial synthesis of polymers (Review)

Existing methods for polymerization in the “living” chain mode are briefly analyzed and opportunities for its use for synthesis of polymeric materials under industrial conditions are considered. Particular examples of application of radical polymerization in manufacture of homo- and copolymers are given, and prospects for development of basic and applied research in this topical area of polymeric chemistry in the nearest years are critically analyzed.

Hydrosilylation of 3,3,4,4-tetrafluorohexa-1,5-diene and 4-bromo-3,3,4,4-tetrafluorobut-1-ene

Fluoroalkylchlorosilanes are of interest as starting material for the synthesis of polymeric materials with some unique properties. The most promising method for the synthesis of these compounds is organofluorine hydrosilylation of unsaturated derivatives. However, the literature on studies of such reactions is rather limited. Common Spayer or Karsted catalysts are mentioned in most papers [1–3]. An exception is the work [4], where Ojima et al. describe in detail the hydrosilylation of 3,3,3-trifluoropropene and pentafluorostyrene catalysed by palladium, rhodium, and ruthenium complexes. When using Rh and Ru catalysts,the reaction proceeds non-selectively that excludes their practical application. Addition of chloroosilanes to fluoroalkenes in the presence of catalysts based on Pt complexes proceeds with high regioselectivity in accordance with Farmer rule. The hydrosilylation of 3,3,3-trifluoropropene with methyldichlorosilane forms the basis for the synthesis of the known SKTFt rubber of high oil and fuel resistance. The interaction of 3,3,4,4,4-pentafluorobut-1-ene with methyldichlorosilane was catalysed by Pt complex described in [5].

Relevant developments and new insights on Sonoelectrochemistry

Sonoelectrochemistry is undergoing a reemerging activity in the last years with an increasing number of papers appearing in a wide range of peer review journals. Applied studies cover environmental treatments, synthesis and characterization of nanostructures, polymeric materials synthesis, analytical procedures, films preparations, membrane preparations among other interesting applications. Fundamental analyses are also carried out focused on electrochemical processes using unconventional solvents, elucidation of mechanisms and combination with other techniques. The interrelation between Electrochemistry and Acoustics presents mutual benefits for both disciplines, providing interesting information about the bubble dynamics for acoustics physicists and a higher number of possible applications for electrochemists. However, the vast majority of this research has been carried out at laboratory scale with individually designed systems based on ultrasonic horns dipped into traditional glass electrochemistry vessels. It is remarkable that even with this rudimentary experimental set-up many interesting results have been generated. However sonoelectrochemistry has suffered a few drawbacks related to reproducibility, scale-up and design aspects which have slowed its development. Almost certainly the reason for this is the lack of reactors that have been purpose built for sonoelectrochemistry. There have been many attempts to build lab-scale systems e.g. for electroanalysis, nanomaterials synthesis and the electrooxidation of organic pollutants but the results are often contradictory. A few groups have attempted to characterize lab-scale sonochemical reactors adapted as sonoelectrochemical reactors but the true optimization of such reactors requires contributions from many disciplines including physics, fundamental and applied electrochemistry, chemical engineering and material science.

Synthesis and Characterization of Polymeric Materials from Vegetable Oils

AbstractAlthough the petrochemical polymers have revolutionized the technological development, the intensive use of these materials have contributed to the global pollution. In this context, researches involving ecofriendliness materials are growing up, as well as, a current interest in developing materials from inexpensive and renewable resources, such as vegetable oils. In this work, is described the synthesis of polymeric materials by thermal polymerization from linseed oil (Linum usitatissimum L.) and passion fruit oil (Passiflora edulis) and their characterization by gas chromatographic (GC), Fourier transform infrared (FTIR) spectroscopy, solubility in organic solvents, thermogravimetry (TG), differential scanning calorimetry (DSC) and Raman spectroscopy. The TG curve shows that those polymeric materials present two stages of decomposition. DSC plots of the vegetable oils showed some endothermic and exothermic transitions which are not present in the DSC curves corresponding to oil‐based polymers. The Raman spectra of the polymers indicate declining of absorbance in the region of CC stretching (∼1600 cm−1). This absorption was used to estimate the degree of polymerization (79% and 67.5% for linseed and passion fruit oils, respectively).

Value-based Polymer Precursors from Paper Waste and its Application in Polyurethane Foams

Increase in generation of the paper waste around the world, especially in developing countries, has created a need to develop new ways to use this waste to obtain value-oriented products. Due to limited availability of petroleum resources and related environmental concerns, petroleum-based precursors for polymeric materials are being replaced by renewable resources, which are abundant in nature and economic. Paper waste is a rich source of cellulose, which can be chemically modified to produce valuable products. Polymeric precursors (polyols) were synthesized by glycosylation of cellulose of paper waste, obtained from magazines and transesterifying the obtained product using castor oil. The synthesized products were characterized by Fourier transform infrared spectroscopy, high performance liquid chromatography, and physicochemical analysis. The resultant polyols were of dark color, low viscosity, % nonvolatile mater <1, hydroxyl value ranging 200—400, moisture content <1%, and acid value <2.5. These synthesized precursors with good characteristics to use it for the synthesis of polymeric materials were used for the synthesis polyurethane foams, which were tested for their physical, mechanical, thermal (thermogravimetric analysis), and morphological (scanning electron micrograph) characteristics.

Enhanced spin capturing polymerization: An efficient and versatile protocol for controlling molecular weight distributions

A study was conducted to demonstrate a control mechanism employing a well-known class of radical spin traps (nitrones) as control reagents to efficiently capture macroradicals by forming irreversibly terminating macronitroxides that both enhance and control cross-termination reactions, thereby allowing for the synthesis of polymeric materials with defined properties. The efficiency and versatility of this technique, called enhanced spin capturing polymerization (ESCP), are exemplified by three distinctively different monomer systems. These monomer systems include the thermal polymerization of styrene and butyl acrylate (BA) in bulk and UV-induced polymerization of N-isopropylacrylamide (NIPAAm) in aqueous solution. The study has also shown how the molecular weight distributions of the polymers prepared through ESCP can be accurately predicted.

Atom transfer radical addition and polymerization reactions catalyzed by ppm amounts of copper complexes

Over the past decade, copper-catalyzed atom transfer radical polymerization (ATRP) has had a tremendous impact on the synthesis of polymeric materials with well defined compositions, architectures and functionalities. Apart from synthetic aspects of ATRP, considerable effort has also been devoted to structural and mechanistic understanding of copper complexes involved in ATRP, as well as development of methodologies to decrease the amount of catalyst needed in these systems. This tutorial review reports on recent advances in the area of catalyst regeneration in ATRP and mechanistically similar atom transfer radical addition (ATRA) using environmentally benign reducing agents. The outlined processes termed ARGET (activators regenerated by electron transfer) and ICAR (initiators for continuous activator regeneration) ATRP enable the synthesis of well-defined (co)polymers and single addition adducts using very low concentrations of copper catalysts (1-100 ppm). Recent developments in this area could have profound industrial implications on the synthesis of well-defined polymeric materials and small organic molecules.

Crystal Engineering with the Uranyl Cation II. Mixed Aliphatic Carboxylate/Aromatic Pyridyl Coordination Polymers: Synthesis, Crystal Structures, and Sensitized Luminescence

Eleven novel U(VI)-containing coordination polymers have been synthesized under hydrothermal conditions and characterized via single-crystal X-ray diffraction and fluorescence spectroscopy. These inorganic/organic hybrid materials represent an important advance in the synthesis of polymeric materials in that multiple organic species have been employed in an effort to influence topology and properties. This family of materials is thus the result of a systematic pairing of the uranyl cation, UO22+, with aliphatic dicarboxylates (see part I, this issue) and the dipyridyl species, 4,4‘-dipyridyl and 1,2-bis(4-pyridyl)ethane. This second organic component assumes a number of roles in these structures, including direct coordination, charge balance, and structure direction. Distinction between which role(s) the dipyridyl species will assume appears to be correlated to the size (length) matching between it and the dicarboxylate linker used. Further, polymerization of primary building units (i.e., monomeric uranyl species) to form novel tetrameric secondary building units is observed in four compounds, possibly as a compensation for size differential between the organic species.

Triterpenic and Other Lipophilic Components from Industrial Cork Byproducts

The detailed chemical composition of the lipophilic extractives of cork and cork byproducts generated throughout industrial processing has been investigated by gas chromatography-mass spectrometry. Triterpenes (cerine, friedeline, and betulinic acid) were the major components detected. Betulinic acid is the main triterpene (11.7 g/kg) identified in industrial cork powder, whereas in black condensates friedeline (95.3 g/kg), betuline (13.1 g/kg), and betulinic acid (12.1 g/kg) are the main triperpenes. Significant fractions of alpha-hydroxy fatty acids (115.1 g/kg) and alpha,omega-dicarboxylic acids (21.2 g/kg) were also detected in black condensate after alkaline hydrolysis. The results demonstrate that these two industrial byproducts can be considered as promising sources of bioactive chemicals or chemical intermediates for the synthesis of polymeric materials.