Polyacrylate glue protein analogs of the glue secreted by Phragmatopoma californica, a marine polycheate, were synthesized with phosphate, primary amine, and catechol sidechains with molar ratios similar to the natural glue proteins. Aqueous mixtures of the mimetic polyelectrolytes condensed into liquid complex coacervates around neutral pH. Wet cortical bone specimens bonded with the coacervates, oxidatively crosslinked through catechol sidechains, had bond strengths nearly 40% of the strength of a commercial cyanoacrylate. The unique material properties of complex coacervates may be ideal for development of clinically useful adhesives and other biomaterials.
Hydrophobically associating polyacrylamides (HAPAMs) were synthesized via inverse suspension polymerization using ammonium persulphate (APS)/tertramethylethylenediamine (TEMED) as the redox initiators, 2-methacryloyloxyethyl n-alkyl dimethyl ammonium bromide (DM-n, n = 8, 12, 16) as the hydrophobic comonomers. The structures of the copolymers were elucidated by FT-IR and ionic chromatographic analysis, respectively. The morphology and particle size of the resultant HAPAMs were characterized by scanning electronic microscope (SEM) and laser particle size analyzer, which revealed that spherical particles were formed and the particle size exhibited Gaussian distribution centered from 25 μ m to 162 μ m. Furthermore, the solution properties of the copolymers were studied with viscometry and the results showed that HAPAMs synthesized under optimal conditions exhibited an obvious viscosity enhancement in aqueous solution and excellent salt-tolerant capability in brine. 相似文献
The strong adhesion ability of mussel foot‐byssal proteins (Mfps) has inspired scientists to develop novel materials for strong and reversible adhesion, coating, antifouling, and many other applications. However, in many cases, the high costs and the tedious preparation steps of such bioinspired materials hamper the process to push them into practical application. Here a simple but effective way (one step) is presented to synthesize a mussel‐inspired glue from two cheap commercially available materials: polyvinyl alcohol (PVA) and 3,4‐dihydroxybenzaldehyde (DBA). This bioinspired hot curing adhesive exhibits a strong bonding ability as high as 17.3 MPa on stainless steel surfaces, which surpasses most of the commercially available adhesives.
Swellable PEG amine/dextran aldehyde composite materials are emerging as a controlled, biocompatible tissue adhesive. We explain how preservation of natural tissue amines provides biocompatibility for PEG/dextran that exceeds the stringent, destructive cyanide‐based chemistry of cyanoacrylates, and adhere far better than fibrin glue. Strategic variations of material composition allow for the improvement of biocompatibility and adhesion strength. Material variations can be tailored to match the needs of specific tissue beds for an array of clinical applications. PEG/dextran cohesive properties are most responsive to variations in the PEG component (number of arms and solid content), while tissue/material adhesion strength is primarily determined by the number of aldehydes in the dextran.
Synthetic substrates with defined chemical and structural characteristics may potentially be prepared to mimic the living ECM to regulate cell adhesion and growth. Hydrogels with cell‐adhesive peptides (0.28 ± 0.03 nmol peptide · cm?2, TTA‐R‐0.5; and 0.91 ± 0.12 nmol peptide · cm?2, TTA‐R‐2.0) and/or micro‐scaled topographical patterns (10, 25, and 80 µm grooves) are prepared using enzymatic polymerization. The adherent morphology and proliferation of C2C12 skeletal myoblasts and human aortic smooth muscle cells (hAoSM) on the hydrogels are studied. The newly developed hydrogels may be useful in investigating the roles of cell adhesion and substrate surface properties in the communication of adherent cells with the ECM.
Starch nanoparticle (SNP)‐based pressure sensitive adhesives (PSAs) with core‐shell particle morphology (starch nanoparticle core/acrylic polymer shell) are produced via seeded, semi‐batch emulsion polymerization at 15 wt% SNP loading (relative to total polymer weight) and 40 wt% latex solids. Crosslinker and chain transfer agent (CTA) are introduced to the acrylic shell polymer formulation at a range of concentrations according to a 32 factorial design to tailor the latex and adhesive properties of SNP‐based latexes. The crosslinker and CTA show no significant effect on polymerization kinetics, particle size, and viscosity. Latex gel content is predicted using an empirical model, which is a function of crosslinker and CTA concentration. Both the gel content and glass transition temperature strongly affect the adhesive properties (tack, peel strength, and shear strength) of the SNP‐based latex films. 3D response surfaces for the adhesive properties are constructed to facilitate the design of SNP‐based PSAs with desired properties. 相似文献
Four different types of cellulosic fines were isolated from refiner mechanical and kraft pulp samples to characterize their chemical and physical properties. The pulp fines were flocculated using four different types of cationically modified polyacrylamides. The extent of flocculation was observed with multiple light scattering apparatus. The maximum adsorption of the polyelectrolytes on the pulp fines was determined by polyelectrolyte titration. It was concluded that it is the combination of the molar mass and the charge density of a polyelectrolyte, as well as the origins and characteristics of the fines which define the adsorption and flocculation behavior. None of these properties alone could fully describe these phenomena, but the molar mass of the polyelectrolyte was the predominant factor. The most important fines characteristics were the charge properties and the microstructure. 相似文献
Miniemulsion polymerization is a promising approach to produce and tailor pressure sensitive adhesives (PSAs). In this paper, a systematic comparison of the adhesive properties of latexes produced by miniemulsion and conventional emulsion polymerization is presented. Specifically, the influence of the total surfactant concentration, chain transfer agent concentration and chemical composition on the final adhesive properties of the polymer 2-ethyl hexyl acrylate/methyl methacrylate/acrylic acid was discerned using a 23 factorial design for each polymerization method. In addition to the adhesive properties (i.e., loop tack, peel strength and shear strength), molecular weight distribution, particle size distribution (PSD) and glass transition temperature were analyzed. The results show that under the conditions used in this work, it is possible to produce PSAs using miniemulsion polymerization, a process wherein monomer droplet nucleation is the dominant particle nucleation mechanism. The use of a miniemulsion polymerization process, as opposed to the conventional emulsion technique, produced several differences such as larger particles sizes and narrower molecular weight distributions. Focusing on the PSA films that exhibited adhesive rather than cohesive failure, the PSA films generated via miniemulsion polymerization displayed higher values of loop tack and peel strength compared to those produced via conventional emulsion polymerization. Shear strength results were strongly dependent on the amount of gel content and sol molecular weight for both cases. 相似文献
Mucoadhesion is defined as the adherence of a synthetic or natural polymer to a mucosal membrane via physical or chemical interactions. Mucoadhesive materials are widely used to develop dosage forms for transmucosal drug delivery via ocular, nasal, esophageal, oral, vaginal, rectal, and intravesical routes of administration. This review will discuss some of the most prominent and recent synthetic methodologies employed to modify polymeric materials in order to enhance their mucoadhesive properties. This includes chemical conjugation of polymers with molecules bearing thiol‐, catechol‐, boronate‐, acrylate‐, methacrylate‐, maleimide‐, and N‐hydroxy(sulfo)succinimide ester‐ groups. 相似文献
We report the preparation of nor-bisabolyl epoxide 13 and its use as a common biomimetic intermediate for the synthesis of nor-sesquiterpenoids. Through a cationic cyclization cascade pathway, we prepared nor-isozizaenol 25 , ultimately constituting an eight-step access to this complex sesquiterpenoid from inexpensive and abundant starting materials. Using a radical cyclization cascade pathway, we prepared nor-cedryl alcohol 26 from the same intermediate. Derivatization of these two products led to the discovery of two potent woody odorants of interest in perfumery. 相似文献
Heat shrinkable tubes and tapes made of irradiated polyethylene have been produced for several years. The memory effect of such products is widely used in many industrial applications. Hot-melt adhesive is often applied to provide better sealing properties of heat shrinkable products.
Radiation grafting of hot-melt adhesives based on PP and copolymers like EVA was investigated. Several monomers were selected for radiation grafting process. Comparison of structural and mechanical properties with nonirradiated material was carried out. 相似文献
Summary: Pressure-Sensitive Adhesives (PSAs) are used for many applications (e.g. tapes and labels), and the market is still growing as new applications are regularly discovered. Emulsion polymerization is widely used to produce water-based PSAs. In this work, the influence of morphology, diameter and acrylic acid concentration in the particles on adhesion properties (peel, tack and shear) was studied. To do so, two series of homogeneous and core-shell latex particles of poly(butyl acrylate-2-ethyl-hexyl acrylate) with different concentrations of acrylic acid (0, 1, 3 and 5 wt%) and three different average diameters, were synthesized by means of emulsion polymerization techniques. The materials were characterized by dynamic light scattering, zeta potential and transmission electronic microscopy. The contents of acrylic acid in the polymer and dispersed medium were determined and the higher quantity of it was found within the particles. The best equilibrium between adhesion properties was found in the core-shell particles with 3 wt% of AA. 相似文献
Plant polyphenols, such as the African potato (Hypoxis hemerocallidea)-derived bis-catechol rooperol, can display promising anticancer activity yet suffer from rapid metabolism. Embarking upon a program to systematically examine potentially more metabolically stable replacements for the catechol rings in rooperol, we report here a general, scalable synthesis of rooperol and analogues that builds on our previous synthetic approach incorporating a key Pd-catalyzed decarboxylative coupling strategy. Using this approach, we have prepared and evaluated the cancer cell cytotoxicity of rooperol and a series of analogues. While none of the analogues examined here were superior to rooperol in preventing the growth of cancer cells, analogues containing phenol or methylenedioxyphenyl replacements for one or both catechol rings were nearly as effective as rooperol. 相似文献
A template Schiff condensation of 2,6-pyridine dicarbaldehyde or 2,6-diformyl-4- bromophenol and 1,3–diamino-2-hydroxy propane or 3,4-diaminotoluene in the presence of copper(II) salts (CuX2) (X = Cl, Br, CH3COO, or ClO4) affords different types of copper(II) complexes. Depending on the employed molar ratio of the dicarbonyl compounds and diamines, different types of copper(II) complexes formed during the template condensation reaction. Structural formulation of the complexes was confirmed by elemental analysis (C, H, N, and M), physical measurements such as thermal analysis (TAG & DTG), molar conductivity, and magnetic moments in addition to spectral studies (UV–Vis, IR, and ESR). Homobinuclear in a four-coordinate square planar and five-coordinate square pyramidal and trigonal bipyramidal in monomeric structures are proposed. A mononuclear hexa-coordinate in an octahedral geometry is suggested as well. Oxidase biomimetic catalytic activity of these newly synthesized copper(II) complexes was examined toward the aerobic oxidation of 4-tert-butylcatechol (4-TBCH2) and o-aminophenol under catalytic conditions. Both catalytic and kinetic investigations demonstrate promising oxidase catalytic activity and based on the kinetic results, probable mechanistic catalytic implications are discussed. Geometrical structures of representative copper(II) complexes were determined by optimizing their bond lengths, bond angles, dihedral angles, and the structural index (τ). 相似文献