Polymerizable Component Research Articles

Fabrication of Ruby by 3D printing of transparent salt solutions

A novel method is presented for fabricating 3D-printed Cr3+-doped α-Al2O3 complex structures, known as Ruby, using digital light processing (DLP) 3D printing and sol-gel reactions based on solutions only. The aqueous printing solution comprises aluminum and chromium chloride as the sol-gel precursor and acrylic acid (AA) as the polymerizable component. After photopolymerization, aging, and sintering at 1150°C, structures shrink up to 28±7 %, achieving a final printing resolution of 55.7±0.7 μm, surpassing the nominal printer’s resolution of 200 μm. Characterization includes X-ray diffraction, scanning electron microscopy, UV-Vis, and fluorescence measurements, revealing crystalline Cr:α-Al2O3 composition emitting at 693 nm. The structures exhibit maximum compression stress of 89±3 MPa and microhardness of 340–500 HV, showcasing potential applications in thermal insulation, jewelry, and mechanical uses.

A processable ionogel with thermo-switchable conductivity.

We report an ionogel with thermo-switchable conductivity and high processability based on physical self-assembly of poly(styrene-b-ethylene oxide-b-styrene) (PS-PEO-PS) in mixed ionic liquids composed of thermo-responsive 1,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide and polymerizable 1-(4-vinylbenzyl)-3-butylimidazolium bis(trifluoromethylsulfonyl)imide, and subsequent chemical crosslinking of the polymerizable component.

A novel conductive composite gel based on polyvinyl alcohol/polymerizable deep eutectic solvent with superior tear resistance, tensile properties and recyclability

The polymerizable deep eutectic gel has become one of the essential materials for wearable electronic devices because of its low volatility, excellent ionic conductivity, and electrochemical stability. Finding strategies to improve the strength of gel-like materials was a huge challenge. In this paper, we present for the first time a deep eutectic solvent (DESD) with hydrogen bond acceptors as polymerizable components. We also discover a new strategy for inducing PVA crystallization with it as the core. Using DESD can induce PVA crystallization extremely easily, avoiding the complicated steps of traditional PVA hydrogels which need to cycle freeze–thaw to induce crystallization. The crystalline domain formed by PVA acts as the physical cross-linking site, greatly enhancing the strength (stress up to 4 MPa, strain up to 1558%) and tear resistance (tearing energy up to 12.3 kJ/m2) of eutectic gel. The fully non-covalent cross-linked structure made eutectic gels have excellent self-healing ability (99%) and recycling ability. This strategy provided a new idea for the preparation of high-strength ionic conductive gel. High strength and recyclability gave gel great development space in the engineering application field.

Reversibly growing crosslinked polymers with programmable sizes and properties

Growth constitutes a powerful method to post-modulate materials’ structures and functions without compromising their mechanical performance for sustainable use, but the process is irreversible. To address this issue, we here report a growing-degrowing strategy that enables thermosetting materials to either absorb or release components for continuously changing their sizes, shapes, compositions, and a set of properties simultaneously. The strategy is based on the monomer-polymer equilibrium of networks in which supplying or removing small polymerizable components would drive the networks toward expansion or contraction. Using acid-catalyzed equilibration of siloxane as an example, we demonstrate that the size and mechanical properties of the resulting silicone materials can be significantly or finely tuned in both directions of growth and decomposition. The equilibration can be turned off to yield stable products or reactivated again. During the degrowing-growing circle, material structures are selectively varied either uniformly or heterogeneously, by the availability of fillers. Our strategy endows the materials with many appealing capabilities including environment adaptivity, self-healing, and switchability of surface morphologies, shapes, and optical properties. Since monomer-polymer equilibration exists in many polymers, we envision the expansion of the presented strategy to various systems for many applications.

Growing Strategy for Postmodifying Cross-Linked Polymers' Bulky Size, Shape, and Mechanical Properties.

Living organisms are open systems that can incorporate externally provided nutrients to vary their appearances and properties, while synthetic materials normally have fixed sizes, shapes, and functions. Herein, we report a strategy for enabling cross-linked polymers to continuously grow with programmable bulky structures and properties. The growing strategy involves repeatable processes including swelling of polymerizable components into the cross-linked polymers, in situ polymerization of the components, and homogenization of the original and newborn polymer networks. Using acrylate-based polymers as an example, we demonstrate that homogenization allows the grown polymer materials to further integrate various polymerizable components to alternate their bulky properties. During the growth, the changes from elastomers to organogels and then to hydrogels with updated covalent-linked functions (i.e., photochromism and thermoresponsiveness) are shown. Since this growing strategy is applicable to different acrylate systems, we envision its great potential in the design of next-generation polymers, smartening systems, and postmodification of cross-linked polymer materials.

Light-regulated growth from dynamic swollen substrates for making rough surfaces

Natural organic structures form via a growth mode in which nutrients are absorbed, transported, and integrated. In contrast, synthetic architectures are constructed through fundamentally different methods, such as assembling, molding, cutting, and printing. Here, we report a photoinduced strategy for regulating the localized growth of microstructures from the surface of a swollen dynamic substrate, by coupling photolysis, photopolymerization, and transesterification together. Photolysis is used to generate dissociable ionic groups to enhance the swelling ability that drives nutrient solutions containing polymerizable components into the irradiated region, photopolymerization converts polymerizable components into polymers, and transesterification incorporates newly formed polymers into the original network structure. Such light-regulated growth is spatially controllable and dose-dependent and allows fine modulation of the size, composition, and mechanical properties of the grown structures. We also demonstrate the application of this process in the preparation of microstructures on a surface and the restoration of large-scale surface damage.

Self-Healing Epoxy Composite with Heat-Resistant Healant

To provide self-healing epoxy composite with adequate heat resistance for high-performance application, we developed a novel microencapsulated epoxy/mercaptan healing agent. The key measure lies in usage of diglycidyl ether of bisphenol A (EPON 828) as the polymerizable component and 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30) as the catalyst. Because of the higher thermal stability of EPON 828 and lower volatility of DMP-30, the healing agent and the self-healing composite not only survive high-temperature curing and thermal exposure, but also offer satisfactory capability of autonomous properties restoration, as characterized by both fracture mechanics and fatigue tests. Especially when the operation temperature is not higher than 200 °C, the performance of the healing system is nearly independent of thermal history.

Study of factors related to performance improvement of self-healing epoxy based on dual encapsulated healant

Our earlier work developed epoxy based self-healing composites with embedded dual microcapsules, which contain unreacted epoxy as the polymerizable component and mercaptan and tertiary amine catalyst as the hardener, respectively. Self-healing was allowed to proceed rapidly, offering attractive repair effectiveness. To give full play to the healing agent, influences of a series of factors on healing chemistry of the composites were studied in this paper. It was found that strong alkality of the catalyst, high activity of mercaptan, and low viscosity of the encapsulated epoxy prepolymer ensured high healing efficiency and rate of healing. In addition, matching of the microcapsules' sizes and fractions was critical for keeping stoichiometric ratio of the components at the damage areas, as required by the mechanism of the healing reaction (i.e. addition polymerization). Homogeneous dispersion of the capsules under proper stirring speed led to timely contacts between the healant fluids flowing out of the fractured capsules. Larger microcapsules favored filling of the cracks in terms of larger amount of the released healing agent, while smaller ones facilitated mixing and interdiffusion of the ingredients. The results provided key data for optimizing the self-healing system.

In situ fabrication of polyacrylate/nanozirconia hybrid material via frontal photopolymerization

Frontal photopolymerization was applied to fabricate polymer/nanozirconia hybrid material by using acrylates as polymerizable components and tetrabutyl zirconate (TBZ) as the precursor of nanozirconia, respectively. The nanozirconia particles were in-situ generated with the polymerization front traveling and gradiently dispersed in the simultaneously formed polymer rod. The iodonium salt was utilized as photoacid generator to produce protonic acid and drive TBZ into nanozirconia particles. With the frontal polymerization traveling downward, the particle size and concentration of zirconia increased, but layer-resolved conversion of TBZ decreased. The particle size of zirconia could be reduced remarkably by the protection of monoalkyl titanate bearing six long chains. The refractive index of the hybrid rod was found to increase from top to down. The top–down layer-resolved storage modulus of the hybrid rod increased due to nanoparticle filling effect but decreased beyond the depth of 4 cm from the top, which may be ascribed to particle aggregation.

Adhesion evaluation on low-cost alternatives to thermosetting epoxy encapsulants

The thermosetting epoxy curing systems have been widely used as encapsulants in the electronic packaging industry. With the continual evolving of electronic product markets, material suppliers have been challenged to provide more options to meet the requirements of advanced, yet cost effective, packaging solutions. In this paper, two low-cost alternative materials have been investigated experimentally regarding their adhesion and reliability performance, and these have then been compared with the thermosetting epoxy systems. One of the materials is thermoplastic bisphenol A epoxy/phenoxy resin, and the other is an interpenetrating polymer network composed of an epoxy curing component and a free radical polymerizable component. Some formulations of the materials being studied could exhibit excellent adhesion, durability and application reliability. While reworkability is expected for these materials, they are promising as cost effective encapsulants for electronic packaging, and may be applied with appropriate processing techniques.

Mass Spectrometric Characterization of a New 2‐Hydroxypropyl‐β‐cyclodextrin Derivative Bearing Methacrylic Moieties and Its Copolymerization with 1‐Vinyl‐2‐pyrrolidone

AbstractThe characterization of a new cyclodextrin (CD) derivative, developed by Wacker Chemie GmbH under the name βW7‐MAHP and consisting of methacrylic moieties attached to hydroxypropyl‐β‐CD units, was investigated in terms of molecular structure and reactivity. The structural study was performed using a matrix‐assisted laser‐desorption ionization time‐of‐flight (MALDI‐TOF) mass spectrometry analysis, which revealed that βW7‐MAHP is a mixture of at least 60 identified compounds. The substituent nature was determined from the two successive chemical modifications performed on β‐CD (hydroxypropylation with propylene oxide followed by the reaction with glycidyl methacrylate). Furthermore, each reaction resulted in a mixture of compounds having different numbers of substituents because of the polyfunctionality of the β‐CD molecule (14 secondary and 7 primary OH groups). Only 50 wt.‐% of the mixture consisted of polymerizable components among which a small proportion contained two or more methacrylic residues. The polymerizability of βW7‐MAHP was studied, and the reactivity ratios in the copolymerization with 1‐vinyl‐2‐pyrrolidinone were estimated. Soluble copolymers were obtained for monomer compositions having a βW7‐MAHP fraction less than 60 mol‐% whereas for higher amounts cross‐linked gels were produced.MALDI‐TOF mass spectrum of βW7‐MAHP.magnified imageMALDI‐TOF mass spectrum of βW7‐MAHP.

Effect of polyacid aqueous solutions on photocuring of polymerizable components of resin-modified glass ionomer cements

Objectives. Resin-modified glass ionomer cements (RMGI) are hybrid materials prepared by incorporation of polymerizable components (typically 2-hydroxyethyl methacrylate (HEMA) with possible addition of multifunctional methacrylates) into a conventional acid–base mixture (a polymeric acid with powdered calcium fluoro-aluminosilicate glasses). During setting, the photopolymerization process and the acid–base reaction affect each other. The aim of this work was to examine the effect of a 45% aqueous solution of poly(acrylic acid) (PAA) and the liquid component of a commercial glass ionomer cement on HEMA and triethyleneglycol dimethacrylate (TEGDMA) photopolymerization. Methods. The polymerization was initiated by 2,2-dimethoxy-2-phenylacetophenone (DMPA) and camphorquinone (CQ)/coinitiator system. The reaction course was monitored under Ar and air by isothermal differential scanning calorimetry. Results. The main effect of addition of polyacid solution (PAA and commercial) up to 10 wt% to HEMA on the polymerization initiated with DMPA was earlier onset of autoacceleration. For the process initiated by the CQ-based system, the addition of 5 wt% of PAA solution strongly accelerated the polymerization and increased the conversion, both in Ar atmosphere as well as in air. TEGDMA photopolymerization was not influenced or slightly retarded by the presence of 3 wt% of PAA solution (the upper limit of solubility), depending on the initiating system used. Significance. Under initiation conditions used in curing of commercial dental products (CQ-based two component initiating system), the presence of polyacid-aqueous solution in HEMA-based photocurable component increases markedly the polymerization rate and the conversion both in Ar atmosphere as well as in air. This result contributes to a characterization of the setting process of RMGIs.

Polyacid‐modified composite (compomer) systems containing polymers of N‐vinylpyrrolidone

AbstractThe objective of this work was to develop polyacid‐modified composite systems (compomers) suitable for dental restoratives in which high molecular weight hydrophilic (co)polymers containing variable amounts of N‐vinylpyrrolidone were incorporated in small amounts. It was expected that the added polymer would become part of a semi‐IPN (interpenetrating network) after the polymerizable components were cured. These systems could absorb water relatively rapidly at the early stages and thus provided good fluoride release. The effect of the addition of the high molecular hydrophilic polymers of varying compositions on the rheological, mechanical and thermal properties of the compomer systems was also investigated. The polymeric additive, significantly improved the rheological characteristics and without having any deleterious effect on the mechanical properties. The coefficient of thermal expansion of the compomers matched more closely with that of tooth structure when the N‐vinylpyrrolidone content of the polymeric additives was increased. Copyright © 2001 John Wiley & Sons, Ltd.

Cytoskeleton in the archaebacterium Thermoplasma acidophilum? Viscosity increase in soluble extracts

Thermoplasma acidophilum has no cell wall, and so its irregular shape implies the presence of a cytoskeleton. When soluble extracts of T. acidophilum were incubated in vitro they increased in viscosity, suggestive of a polymerizable component. Optimal conditions for the viscosity increase coincided with physiological ionic concentrations. Electron micrographs of negatively stained extracts showed a meshlike lattice of elements 10 nm in diameter similar to nuclear lamins. However, immunologically there was no cross-reaction with lamins nor with the other eukaryotic cytoskeletal proteins tested: tubulin, calmodulin, giardin, actin or myosin.

Synthesis and bioactivity of copolymers with fragments of heparin

A new type of biocompatible copolymer comprising small fragments of heparin, (octa- to dodecasaccharides) copolymerized with a synthetic monomeric component, viz. acrylamide, has been prepared. The heparin fragments are produced by enzymatic or chemical means and are copolymerized, directly or after suitable derivatization, with acrylamide as the major polymerizable component. The polymeric material incorporates the heparin segments as pendant moieties such that their essential functional groups and structural features for specific binding with the selective serine protease coagulation factor inhibitor antithrombin III are preserved. An important feature of this copolymer is its biocompatibility which relates specifically to its antithrombotic and antithrombogenic activity derived from those of heparin fragments. The biological activity of heparin fragments and copolymers thereof are determined in terms of APTT and anti-Xa activity, their antithrombotic potential being expressed as a ratio of anti-Xa activity to APTT. The copolymers reported have biological activities similar to equivalent amounts of respective heparin fragments, and show higher antithrombotic activity compared to intact heparin or commercially available low-molecular-weight heparin (4,000-6,000 Da).

(−)-(9Z)-1,9-Heptadecadiene-4,6-diyn-3-ol as a Principal Component of the Resinous Sap of Evodiopanax innovans Nakai, Japanese Name, Takanotsume, and Its Role in an Ancient Golden Varnish of Japan

Abstract (−)-(9Z)-1,9-Heptadecadiene-4,6-diyn-3-ol was for the first time isolated in high yield (29%) from the resinous sap of Evodiopanax innovans Nakai, Araliaceae. This compound has been associated with the main polymerizable component of an ancient golden varnish. It has also been associated with a phytoalexin and a defense material which produces a water-insoluble coating film by photopolymerization under sunlight for a Takanotsume tree upon being wounded.

Polymerization characteristics of a dye of anthraquinone

AbstractA technical dye of the anthraquinone type was analyzed by GPC, mass spectroscopy, and elemental analysis. Along with the polymerizable component, N‐[4‐amino‐3‐methoxyanthraquinonyl‐(1)] methacrylamide (I), it contained a saturated admixture, N‐[4‐amino‐3‐methoxyanthraquinonyl‐(1)]‐2‐chloro‐2‐methylpropionamide (II). The homopolymerization of I was carried out, and admixture II was isolated and characterized. The copolymerization of the dye with styrene and methyl methacrylate was verified, and the retardation effect of II on the polymerization of these monomers was evaluated.

Compound Membranes of Linearly Polymerized and Cross‐Linked Macrolipids with Phospholipids: Preparation, Microstructure and Applications

AbstractMethods for the assembly and for studying the structural and dynamic properties of partially polymerized membranes are described. Mixtures of two classes of polymerizable amphiphiles with diacyl phosphatidylcholines are studied: (1) phosphatidylcholines carrying a diacetylene group per chain (abbreviated as (m,n)‐DIINPC (where m + n + 6 equals number of C‐Atoms per chain) and (2) a phospholipid‐like molecule with a polymerizable methacryl ligand connected to the phosphate head group via (CH2CH2O)m spacers which is abbreviated as (m.n)‐POMECY (n = number of C‐atoms per chain). — Phase diagrams of the lipid mixtures are established by static light scattering in combination with freeze fracture electron microscopy. The latter technique is also used to study the microscopic organization of the components before and after polymerization. Measurements of lateral diffusion by the photobleaching technique allow to determine (1) the fraction of lipid polymerized and (2) the liquidus and solidus lines of individual vesicles. — By suitable choice of the chain lengths of the components, giant vesicles with DIINPC's can be prepared in such a way that they are stable against transitions into the solid state which is a prerequisite for polymerization of this lipid. For that, use is made of the domain‐like lateral organization of the lipid components. The cross‐linked DIINPC‐domains exhibit a structure reminiscent of a two‐dimensional sponge with inclusions (microdomains) of monomeric lipid embedded into the network. The mechanical stability of the vesicles against repeated transitions through the phase changes is established by phase contrast microscopy and the tightness by a fluorescence technique. By absorption spectroscopy the existence of a “red” and a “white” species of macrolipid is established. — The mixed vesicles with POMECY exhibit a much mechanical stability against phase changes but are less tight with respect to leakage of small dye molecules. By freeze fracture electron microscopy the degree of polymerization was estimated to N ⌣︁ 100. These membranes behave as two‐dimensional macromolecular solutions up to about 10 mole‐% of the polymerizable component. Above this limit lateral decomposition into a dilute solution and a two‐dimensional polymer melt occurs.

W/O MICROEMULSION OF POLYKERIZABLE COMPONENTS

Abstract W/0 microemulsions, containing only polymerizable components in addition to the water, were polymerized at 50° C and the concentration regions in which transparent solids were obtained were observed. The results showed the water content to be limited to the magnitude of 10-20%.

Investigation of the properties of films obtained by the curing of a plastisol system modified by reactive oligomers

A study has been made of the properties of films prepared from PVC plastisols modified by oligoester acrylates. Extremal dependences have been revealed for the glass temperature T g and the yield point T y of the cured thermoreactive PVC plastisols plotted against the concentration of the polymerizable component. It is shown that rheological, thermomechanical and physicomechanical properties of the plasticized PVC depend on the degree of polymerization of oligoester acrylates under conditions of dilution by nonreactive dioctylphthalate. Light has been shed on the role of oligoester acrylate functionality. The regularities obtained are hypothetically explained from the viewpoint of the crosslinking process taking place via a stage of β-polymerization and in terms of the microheterogeneity of the polymer-oligomer system.