Diffusion Of Polymer Chains Research Articles

Discussion on the microscale geometry as the dominant factor for strength anisotropy in material extrusion additive manufacturing

This paper presents a discussion and interpretation of the findings in the review paper “Fused filament fabrication of polymer materials: A review of interlayer bond” by Xia Gao, Shunxin Qi, Xiao Kuang, Yunlan Su, Jing Li, Dujin Wang [Additive Manufacturing (2020): 101658]. This discussion draws different conclusions based on the microscale filament geometry of interlayer bonds as opposed to molecular-scale bonding (diffusion and entanglement of polymer chains), which is predominantly considered in the review. Four complementary arguments on the matter are proposed, demonstrating that microscale geometry rather than incomplete molecular bonding is the predominant cause of strength anisotropy in material extrusion additive manufacturing (MEAM). These arguments consider the evidence from studies that (i) factored microscale geometry into strength calculation; (ii) eliminated the influence of geometry; (iii) improved the geometry to reduce its impact on strength, and (iv) tested the effect of manually reproduced interlayer geometry in bulk material. Overall, this discussion suggests that the underlying cause of anisotropy in MEAM is filament-scale geometric features (grooves and voids between layers), not the deficient bonding as is often theorised. Drawing upon the evidence in the literature, this discussion proposes that specimens attain bulk material strength for a range of printing conditions and materials.

Self-Exchange of Polyelectrolyte in Multilayers: Diffusion as a Function of Salt Concentration and Temperature

Polymer chain diffusion within a hydrated polyelectrolyte complex, PEC, has been measured using an ultrathin film format prepared by the layer-by-layer method. Isotopically labeled self-exchange of deuterated poly(styrene sulfonate), dPSS, with undeuterated PSS of the same narrow molecular weight distribution permitted reliable estimates of whole-molecule diffusion coefficients, D. Narrow molecular weight distribution poly(diallyldimethylammonium), PDADMA, was used as the polycation for the PEC. Extensive pretreatment of starting films was undertaken to remove residual stress, anisotropy, and layering. PSS/PDADMA “multilayers,” PEMUs, thin enough to provide substantial exchange of polyelectrolyte, even with diffusion coefficients as low as 10–16 cm2 s–1, as a function of salt concentration and temperature were measured for this PEC, which has a glass-transition temperature, Tg, close to room temperature. Two molecular weights of dPSS, about 15 and 100 kDa, presumed to be below and above the entanglement molecular weight, respectively, both diffused faster at higher temperatures with respective activation energies, Ea, of about 21 and 53 kJ mol–1, the latter about the same as Ea for the place exchange between two pairs of PSS:PDADMA. Studies of the linear viscoelastic response of macroscopic PECs showed a difference of about 8 °C in the Tg of the two lengths of PSS complexed with the same PDADMA. Increasing concentrations of NaCl influenced D of 100 kDa PSS but not 15 kDa PSS at room temperature. D was faster in the region of the film near the solution interface, again attributed to a lower Tg caused by greater water content at this interface.

Diffusion of Short Semiflexible DNA Polymer Chains in Strong and Moderate Confinement.

In many technological applications, DNA is confined within nanoenvironments that are smaller than the size of the unconfined polymer in solution. However, the dependence of the diffusion coefficient on molecular weight and characteristic confinement dimension remains poorly understood in this regime. Here, convex lens-induced confinement (CLiC) was leveraged to examine how the diffusion of short DNA fragments varied as a function of slit height by using single-molecule fluorescence tracking microscopy. The diffusion coefficient followed approximate power law behavior versus confinement height, with exponents of 0.27 ± 0.01, 0.32 ± 0.02, and 0.42 ± 0.06 for 692, 1343, and 2686 base pair chains, respectively. The weak dependence on slit height suggests that shorter semiflexible chains may adopt increasingly rodlike conformations and therefore experience weaker excluded-volume interactions as the confinement dimension is reduced. The diffusion coefficient versus molecular weight also exhibited apparent power law behavior, with exponents that varied slightly (from -0.89 to -0.85) with slit height, consistent with hydrodynamic interactions intermediate between Rouse and Zimm model predictions.

Weibull Modeling of Controlled Drug Release from Ag-PMA Nanosystems.

Traditional pharmacotherapy suffers from multiple drawbacks that hamper patient treatment such as antibiotic resistances or low drug selectivity and toxicity during systemic applications. Some functional hybrid nanomaterials are designed to handle the drug release process under remote-control. More attention has recently been paid to synthetic polyelectrolytes for their intrinsic properties which allow them to rearrange into compact structures, ideal to be used as drug carriers or probes influencing biochemical processes. The presence of Ag nanoparticles (NPs) in the Poly methyl acrylate (PMA) matrix leads to an enhancement of drug release efficiency, even using a low-power laser whose wavelength is far from the Ag Surface Plasmon Resonance (SPR) peak. Further, compared to the colloids, the nanofiber-based drug delivery system has shown shorter response time and more precise control over the release rate. The efficiency and timing of involved drug release mechanisms has been estimated by the Weibull distribution function, whose parameters indicate that the release mechanism of nanofibers obeys Fick’s first law while a non-Fickian character controlled by diffusion and relaxation of polymer chains occurs in the colloidal phase.

Microstructure–sealing performance linkage of metallocene linear low density polyethylene and low density polyethylene blends

The microstructure–sealing performance linkages of linear low density polyethylene (LLDPE) and low density polyethylene (LDPE) blends using thermo-rheological tools are discussed. The effect of molecular architecture in metallocene catalyzed LLDPE (mLLDPE), Ziegler–Natta catalyzed LLDPE (ZN-LLDPE) on the miscibility, and rheological behavior of the blends with LDPE is shown. Even though the macro parameters like density, melt flow rate of the LLDPEs are comparable, subtle differences in the microstructure manifested by comonomer type and its distribution across molecular weight affects the sealing performance of the LLDPE/LDPE blends. For LLDPE matrix, tailor-made comonomer distribution affording thinner lamellas (viz., thickness <11.8 nm) is more critical to sealing process than having total higher comonomer content. For LLDPE/LDPE blends, the thicker lamellae of main chain polymer of LDPE co-crystallize with homo-polyethylene like fraction of LLDPE. The co-crystallization of LLDPE and LDPE helps to achieve hot tack sealing at lower percentage of molten polymer and it appears to be the dominating factor over diffusion of polymer chains across the melt interface to achieve sealing.

Optimization of intrinsic self-healing silicone coatings by benzotriazole loaded mesoporous silica

Multifunctional intrinsic self-healing polymers (ISP) are gaining increasing attention these days, and many studies have been devoted to solving the conflict between achieving high mechanical polymer strength and active polymer chain diffusion. In this research, we developed an optimized self-healing composite coating by adding Benzotriazole (BTA) loaded nano silica (SiO2@BTA) to a dynamic cross-linked Polydimethylsiloxane (PDMS) network，which allows substantial and fast healing of the material integrity upon damage due to the hydrogen interaction between urea and BTA. BTA leaching tests demonstrated a longer release profile during the coating service life and corrosion tests in a 3.5 wt% NaCl aqueous solution indicated that the SiO2@BTA modified PDMS coating shows enhanced corrosion protection of carbon steel upon coating damage. Moreover, after addition of SiO2@BTA, the material failure strength increased from ~1.5 MPa to ~5.5 MPa, and the healing efficiency increased from ~59% to ~90% for 24 h healing at room temperature. Above all, this research provides an intrinsic self-healing coating design method to improve the mechanical strength and the self-healing ability of the ISP as well as enhancing the coating's corrosion protection ability.

Relationship between pore structure with residual pore and mechanical properties of expanded graphite nanocomposites at varying molding pressures

AbstractThe main challenges of developing expanded graphite (EG) composites are to improve the diffusion of polymer chains into EG pores and consequently to reduce the residual pore as defects in the final composites. In this paper, composites of unsaturated polyester (UP) resin containing 0.75 wt% EG are prepared at varying molding pressures of 1, 10, 20, and 30 bar. The EG particles are prepared at different exfoliation temperatures in the range of 700 to 900°C to have EGs with different porous structures. The scanning electron microscopy (SEM) micrographs show that residual pores are observed in the composites prepared at a low pressure of 1 bar. However, when the molding pressure increases, the number of the residual pores decreases and consequently the flexural properties improve. The highlighted improvements achieved by increasing the molding pressure from 1 to 30 bar are a decrease in the value of the residual pore from 23% to 3%, an increase in the flexural modulus from 1523 to 1744 MPa, and an increase in the flexural strength from 30.6 to 54.5 MPa. Interestingly, applying higher molding pressure affects the composites containing EGs with the highest degree of porosity, or rather larger pores, more remarkably.

Simulation study on the critical adsorption and diffusion of polymer chains on heterogeneous surfaces with random adsorption sites.

The critical adsorption and diffusion of a linear polymer chain on a heterogeneous surface with randomly distributed adsorption sites are studied using dynamic Monte Carlo simulations. Results show that the critical fraction of the adsorption sites at which critical adsorption takes place decreases exponentially with the increasing polymer-surface attraction strength and, at the same time, decreases with the increasing intra-polymer attraction strength. For adsorbed polymers with large intra-polymer attraction strength, we also find an adsorption-induced structural transition from a three-dimensional compact globule to a two-dimensional compacted pancake with an increasing fraction of adsorption sites. Anomalous sub-diffusion is observed for the adsorbed polymer diffusion on heterogeneous surfaces, in contrast to the normal diffusion on a homogeneous surface. The polymer on heterogeneous surfaces shows larger fluctuation in the total surface attraction energy and a longer waiting time.

Formulation and evaluation of sertaconazole nitrate loaded nanosponges for topical application

The aim of present research work is to formulate sertaconazole nitrate an antifungal drug into nanosponges loaded topical hydrogel using simple and cost effective method. Nanosponges loaded hydrogels were prepared by “Emulsion solvent diffusion method” using different polymers like ethyl cellulose and polymethyl methacrylate, a surfactant named polyvinyl alcohol and a crosslinking agent dichloromethane. Taguchi experimental design (L8) was applied for screening nanosponges by taking independent variables as type of polymers (X1), concentration of surfactant (X2) and amount of crosslinking agent (X3) while percentage entrapment efficiency (Y1) is dependent variable. Further, they were evaluated for particle size, PDI, zeta potential, percentage yield, entrapment efficiency, in-vitro and ex-vivo diffusion studies. Formulation F2 was screened based on its percentage drug release from in-vitro diffusion studies. Ex-vivo studies were conducted for screened formulation, marketed formulation (Onabet), pure drug dispersion and control gel to determine there percentage drug release and skin retention. F2 formulation followed zero order kinetics with Higuchi release mechanism, which indicates the rate of drug release through the mode of diffusion. The value of ‘n’ from korsemeyerpeppas indicates the anomalous transport concluding the drug release both by diffusion and relaxation of polymer chains. F2 formulation have shown 70.40% skin retention which was more when compared with marketed formulation, pure drug dispersion and control gel. The study concluded that sertaconazole nitrate loaded nanosponges have control release effect for prolonged period of time in the skin and it has been reported to show site targeted effect with reduced incidence of side effects and dosing frequency for the treatment of skin disorders like athelete's foot, dermatophytosis and candidiasis.

Structured, Composite Nanoparticles from Emulsion Polymerization - Morphological Possibilities.

Emulsion polymerization allows the creation of aqueous dispersions of polymer nanoparticles in the 50-500 nm size range, and these products (synthetic latexes) have been made at commercial scales for nearly a century. In the latter half of that period, there emerged a wide variety of nanoparticles composed of two, phase-incompatible materials producing composite particles having a large number of morphological features. Among those are the so-called core-shell, occluded, multilobed, hollow, and mixed structures. This has led to advanced materials serving markets for impact-resistant plastics, architectural and industrial coatings, adhesives, low density opacifiers, printing inks, among others. As the need for such materials has grown, the chemical and physical mechanisms that control the development of particle structure have been substantially investigated and much progress has been made. The objective of the following discussion is to describe the scientific and engineering principles at play when creating these composite particles and to demonstrate how the balance of thermodynamic equilibrium conditions and kinetic limitations (chemical reaction and polymer chain diffusion) combine and/or compete to result in particular morphologies. Many examples are presented.

Chain conformation and dynamics in ultrahigh molecular weight polyethylene melts undergoing extensional–shear coupled flow: insight from dissipative particle dynamics simulation

AbstractA first attempt is made to present a detailed mesoscopic‐level description of the conformation and equilibrium dynamic properties of macromolecular chains in ultrahigh molecular weight polyethylene/polypropylene blends driven by extension‐dominated coupled flow, in comparison with shear‐dominated coupled flow. Extension‐dominated coupled flow can be defined as = 0.005, ≥ 0.1 and shear‐dominated coupled flow as = 0.1, ≥ 1, as verified by the time‐dependent evolution tendency of cell parameters and velocity profiles along the x, y, z directions. In the case of extension‐dominated coupled flow, the chains are greatly elongated and prefer to align along the flow direction, where the polypropylene chains appear to form a somewhat uniform layer. By comparison, the macromolecular chains assume a highly collapsed conformation and have a greater preference to align themselves perpendicular to the flow direction under shear‐dominated coupled flow, which can be ascribed to the rapid diffusion of polymer chains and a minor role of the weak van de Waals interaction in structural transitions. Analyses of conformational behavior derived from dissipative particle dynamics trajectories can, in general, serve as a useful guideline for experimental investigations of ultrahigh molecular weight polyethylene based materials prepared by eccentric rotor extrusion. © 2020 Society of Chemical Industry

Understanding the viscosity decline of poly(amic acid) solution from the correlation point of view

The effects of storage time and temperature on the properties of poly(amic acid) (PAA) solution were re-examined by dynamic and static light scattering. One fast and one slow relaxation modes were observed in fresh prepared semidilute solution. The fast mode corresponds to cooperative diffusion of chain segments inside each “blob” while the slow mode comes from the long-range correlated concentration fluctuation of transient network. Chains relaxation during storage at room temperature (20 °C) leads to the disentanglement of transient network and viscosity drop, thereby only one fast relaxation mode was observed which was related to the mutual diffusion of separated polymer chains. Cooling (to 2 °C) rejuvenates the solution to a certain extent, by which the slow relaxation mode can be regenerated and viscosity re-rises. These results indicate that PAA solutions experience a slow thermodynamic and kinetic transition during storage. Hydrolysis may not be the only reason responsible for the viscosity decrease of the PAA solution, the arrangement of chain conformation during storage should be accounted for.

Prediction of interlayer strength in material extrusion additive manufacturing

The interlayer strengths of parts produced through material extrusion (also referred to as fused filament fabrication or FFF) suffer due to poor interlayer contact and insufficient diffusion. A model for predicting interlayer contact, based on pressure-driven flow, is combined with a model for polymer chain diffusion to predict the interlayer strength (aka, bond strength) of material extrusion parts. Interlayer contact is predicted based on in-line pressure measurements while diffusion is predicted based on in-line temperature and viscosity measurements, demonstrating that a combination of the appropriate in-line sensors and models can be used for real-time monitoring and process control. The interlayer strength model is successfully validated against strength measurements of parts made with high impact polystyrene, indicating that the strength of all parts suffers due to incomplete interlayer contact while only some parts suffered from incomplete diffusive healing. The melt pressure and in-line rheological measurements have proven extremely valuable for understanding the material extrusion process, optimizing quality, and monitoring consistency. Practical insights from the model are provided about how to select appropriate materials and processing conditions, and it concludes with a demonstration of using the in-line sensors and real-time modeling for defect detection.

Thermogravimetric and dynamic mechanical analysis of woven glass/kenaf/epoxy hybrid nanocomposite filled with clay

ABSTRACT This research studies the thermogravimetric and dynamic mechanical analysis of woven glass/kenaf/epoxy hybrid nanocomposites filled with clay. Epoxy resin modified with 1.0 wt% silicon is sonicated with varying clay loading of 1.0, 3.0 and 5.0 wt%. The resin is then spread onto alternating woven glass and NaOH-treated woven kenaf. Thermogravimetric analysis (TGA) reveals the benefits of dispersing clay onto the thermal properties of nanocomposite. Higher residue and higher temperature at 10 wt% mass loss is observed in clay nanocomposite. In addition to that, kenaf treatment, woven glass reinforcement and epoxy modification also help in improving the thermal stability of composites. Dynamic mechanical analysis (DMA) reveals that TKG1% composite possessed the highest storage modulus at room temperature with 136.74% higher than UKG1% composite due to the polymer chain diffusion between well dispersed clay structures. TKG1% also achieved the highest loss modulus which indicates strongest internal friction among other composites. Despite that, TKG1% composite exhibited the lowest Tg which is 72°C. This could be reasoned with the elimination of hemicellulose due to fibre treatment that is responsible for stiffness in natural fibre. Elimination of hemicellulose is proven through Fourier-transform Infrared Spectroscopy (FTIR) analysis conducted on treated kenaf fibre at wavenumber 1514, 1696 and 1726 cm−1.

Molecular Dynamics Simulation on the Scaling Relation of Single Polymer Chain Diffusion on Single Wall Carbon Nanotube

ABSTRACT The diffusion of polymer confined on the surface has been an important topic of interest in polymer science. Extensive research has been done on the scaling relation between diffusion coefficient and chain length for polymer confined in flat two-dimension surface and three-dimension bulk. More work is still needed to be done on the polymer confined on a curved surface. In the present work, the molecular dynamics method is used to simulate the diffusion of a single polymer chain with different lengths on single-wall carbon nanotube. We investigate the influences of the temperature and the nanotube diameter on the scaling relation between the diffusion coefficient and the chain length. The results show that the scaling relation is independent on the temperature. However, the nanotube diameter influences the scaling relation obviously. With the nanotube diameter increasing, the scaling exponent increases.

On the effect of particle surface chemistry in film stratification and morphology regulation.

Combinations of colloids and binders are often used to formulate functional coatings. In these mixtures, competition between particle migration, polymer chain diffusion, evaporation and sedimentation affects their respective spatial location and therefore can govern the surface features. In addition to this, the surface chemistry of the nanoparticles (NPs) and the resulting interparticle interactions can play a significant role in dictating the morphology and the properties of resultant films. Hence it would be possible to tune the surface and bulk topology of the films by controlling these parameters. A combination of various acrylic binders with two types of silica sols, bare (BSiO2) and modified silica (MSiO2), differing in their ability to gel, were formulated and dried under controlled conditions. Factors influencing the mobility and migration of binder and silica particles were evaluated with respect to particle concentration and drying rate. MSiO2 films showed prominent pores with gradual increase in Si% across the cross-section of the films, whereas, BSiO2 films had no pores and showed a uniform Si content across the cross-section of the films. This difference is explained by the variation in gelation between BSiO2 compared to MSiO2, that hindered the NPs migration and affects the infiltration and stratification process. This study paves a path forward to achieve desired surface and bulk porosity from colloidal silica coatings by effective control of chemistry of particles along with process parameters.

Mechanics of self-healing thermoplastic elastomers

Self-healing polymers crosslinked by dynamic bonds have shown great potential in various engineering applications ranging from electronics to robotics. Due to the intrinsic weakness of dynamic bonds, most of the existing self-healing polymers have relatively weak mechanical strengths. To address this drawback, it is proposed to incorporate crystalline domains within the polymer matrix during the synthesis to make tough and strong self-healing thermoplastic elastomers with semi-crystalline phases. Despite the success in the polymer synthesis, the theoretical understanding of self-healing thermoplastic elastomers remains elusive. In this paper, we develop a theoretical framework to model the constitutive and healing behaviors of self-healable thermoplastic elastomers with both dynamic bonds and semi-crystalline phases. We model the virgin thermoplastic elastomer by using a spring-dash model that couples the soft rubbery phase and the stiff crystalline phase. The rubbery polymer network is formed by layering the body-centered unit cubes that link polymer chains via dynamic bonds. Then, the healing is considered as a coupling of polymer chain diffusion and dynamic-bond binding, leading to an effective diffusion-reaction model. Based on the theoretical framework, we can model the stress-strain behavior of the virgin and healed polymers and theoretically explain the relationship between the healing strength and the healing time. The model can consistently explain our own experiments on self-healable thermoplastic elastomers polyurethane and the documented experiments on self-healable thermoplastic elastomers with disulfide bonds and π-π interactions.

Physicochemical characterization and release properties of oral drug delivery: A pH-sensitive nanocomposite based on sodium alginate–pectin–tannic acid–silver

A pH-sensitive nanocomposite formed from sodium alginate (SA)/pectin (Pec)/tannic acid (TA)–silver (Ag) was developed using microwave irradiation and it was applied as a carrier for propranolol drug. TA acts as a cross-linker and a reducing agent for Ag ions. Physicochemical characteristics of the fabricated system using Fourier transform infrared spectroscopy, X-ray diffraction, field-emission scanning electron microscope, high-resolution transmission electron microscope, dynamic light scattering instrument, and energy dispersive X-ray analysis. The swelling percent and the drug release were observed to be pH-sensitive. The occurrence of Ag nanoparticles in the network enhances the drug release that is 96% at pH 7.4 within 420 min. The drug release data were adjusted into different kinetic models involved zero order, first order, Higuchi, and Ritger–Peppas models. The release mechanism is a non-Fickian character where it controls by diffusion and relaxation of polymer chains. It can be concluded that SA/Pec/TA-Ag nanocomposite is a candidate for the oral drug carrier specific for the intestinal system and has ability against the gastric fluid.

Material Extrusion-Based Additive Manufacturing with Blends of Polypropylene and Hydrocarbon Resins

Filament-based material extrusion additive manufacturing (MEAM) is one of the most commonly used techniques in additive manufacturing (AM). In spite of recent notable development in the MEAM process, there is still a need to develop more materials that can be printed consistently using this technique. Isotactic polypropylene (PP), a popular thermoplastic material, undergoes rapid crystallization and subsequent volume contraction. This can lead to residual stress buildup in PP parts when processed using MEAM, resulting in poor adhesion to the printing platform, poor geometric tolerance, and mechanical performance. In this work, the effects of varying composition of low molecular weight hydrocarbon resins incorporated to PP are investigated. Specifically, the thermal behavior, crystallization, morphology, and printability of the blends are studied. The rapid crystallization of PP has been delayed by the addition of hydrocarbon resins that provided a larger time window for the residual stresses to relax. The addition of the resins to the pure PP matrix lowers the crystallization temperature of PP from 121.8 to 116.0 °C, which further enables additional diffusion during the solidification process. Polarized optical microscopy demonstrates the differences in crystalline morphology, which is expected to impact the structure at the interlayer boundaries between deposited layers. The combination of modifications in crystallization rate, time, and morphology significantly affects the interlayer adhesion and residual stress state, which directly controls the mechanical properties and part warpage of printed parts. Tensile bars of the different blends were printed in two different orientations to analyze the mechanical performance and study part anisotropy. The maximum tensile stress of pure PP (26.8 ± 2.1 MPa) printed at a ±45° raster angle increased with addition of 20 wt % hydrocarbon resin (32.4 ± 3.0 MPa) when printed under the same conditions. The improvement in the tensile strength is due to a combination of changes in crystallinity, morphology, and improved interlayer adhesion during printing. The parts were annealed postprinting to improve polymer chain diffusion across the layers, thereby improving interlayer adhesion and resulting in tensile modulus and strength values in excess of 90% of injection-molded PP parts.

The Impact of the Ionic Cross-Linking Mode on the Physical and In Vitro Dexamethasone Release Properties of Chitosan/Hydroxyapatite Beads.

In this study, the effect of the ionic cross-linking mode on the ability to control physical properties and in vitro release behavior of the dexamethasone (DEX) drug from chitosan (CS) and chitosan/hydroxyapatite (CS/HA) beads was investigated. CS solutions without and with HA and DEX were dripped into two coagulation solutions, prepared with a non-toxic ionic crosslinker (sodium tripolyphosphate, TPP) and distilled water, one at pH = 9.0 and other at pH = 6.0. Optical microscopy (OM) and scanning electron microscopy (SEM) results showed changes on the surface topology of the beads, with a reduction of roughness for beads prepared at pH = 6.0 and an increase for the one prepared at pH = 9.0. The diameter and sphericity of the beads prepared at pH = 6.0 proved more uniform and had a larger pore size with a good interconnectivity framework. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) suggested a higher crosslinking degree for beads prepared at pH = 6.0, corroborated by X-ray diffraction profiles (XRD) analysis that indicated a decrease in the crystalline structure for such beads. In in vitro drug release data, all beads presented a sustained release during the studied period (24 h). The drug release rate was affected by the pH of the coagulation solution used in the preparation of the beads. The in vitro kinetics of the release process was of the Peppas–Sahlin model, controlled by both diffusion and relaxation of polymer chains or swelling (anomalous transport mechanism). Our results suggest that DEX-loaded CS/HA beads, crosslinked in TPP coagulation solution at pH = 9.0, led to a decrease in the DEX release rate and prolonged the release period. Thus, this composition might have prospective as a functional material for bone and cartilage tissue engineering.