Polyhydroxyalkanoates Composites and Blends: Improved Properties and New Applications

Composites of Polyhydroxyalkanoates (PHAs) have been proven to have enhanced properties in comparison to the pure form of these polyesters. Depending on what polymer or material is added to PHAs, the enhancement of different properties is observed. Since PHAs are explored for usage in diverse fields, understanding what blends affect what properties would guide further investigations towards application. This article reviews works that have been carried out with composite variation for application in several fields. Some properties of PHAs are highlighted and composite variation for their modulations are explored

Electrospinning of Fiber Matrices from Polyhydroxybutyrate for the Controlled Release Drug Delivery Systems

The submission provides an overview of current state of the problem and authors’ experimental data on manufacturing nonwoven fibrous matrices for the controlled release drug delivery systems (CRDDS). The choice of ultrathin fibers as effective carriers is determined by their characteristics and functional behavior, for example, such as a high specific surface area, anisotropy of some physicochemical characteristics, spatial limitations of segmental mobility that are inherent in nanosized objects, controlled biodegradation, and controlled diffusion transport. The structural-dynamic approach to the study of the morphology and diffusion properties of biopolymer fibers based on polyhydroxybutyrate (PHB) is considered from several angles. In the submission, the electrospinning (ES) application to reach specific characteristics of materials for controlled release drug delivery is discussed

Пленочные материалы на основе полиэтилена с наночастицами кремния и карбида кремния

Polyethylene films containing 0.1-1.5% of mass of n-SiС and n-Si nanoparticles have been produced by the extrusion method. Using the spectral analysis method, it was found that the obtained films absorb UV radiation in the range 200-400 nm, which is harmful to organic substance. The average particle sizes and the quality of their dispersion in the films were determined by X-ray diffraction analysis. Using differential scanning calorimetry and physical and mechanical tests, it was found that nanoparticles did not affect the formation of the internal structure of the matrix polyethylene. The degree of crystallinity, the melting point and crystallization remain unchanged. The properties of the film surface, studied by the tribological, triboelectric methods and the determination of the wetting angle, remain constant and do not differ from the properties of PE films with nanoparticle content 0.1-1%. At 1.5% n-SiC content, a change in the surface microrelief is diagnosed, leading to a slight increase in the friction coefficient of the films. The polyethylene films filled with n-SiС and n-Si obtained in this work are recommended for use as UV protective coatings for various purposes.В настоящей научно-исследовательской работе экструзионным способом были получены полиэтиленовые пленки, содержащие 0,1-1,5% (мас.) наночастицы n-SiС и n-Si, полученные плазмохимическим методом. С помощью спектрального метода анализа установлено, что полученные пленки поглощают УФ-излучение в диапазоне 200-400 нм, губительное для органической материи. Методом рентгеноструктурного анализа были определены средние размеры частиц и качество их диспергирования в пленках. Методами дифференциальной сканирующей калориметрии и физико-механических испытаний установлено, что наночастицы не влияют на формирование внутренней структуры полиэтилена (ПЭ) матрицы. Степень кристалличности, температуры плавления и кристаллизации остаются неизменными. Свойства поверхности пленок, исследуемые трибологическими, трибоэлектрическими методами и определением краевого угла смачивания, остаются постоянными и не отличаются от свойств ПЭ-пленок при содержании наночастиц от 0,1 до 1%. При 1,5% содержании n-SiС диагностируется изменение микрорельефа поверхности, приводящее к небольшому росту коэффициента трения пленок. Полученные в работе наполненные n-SiС и n-Si полиэтиленовые пленки рекомендуются для использования в качестве УФ защитных покрытий различного назначения

Thermo-oxidative destruction and biodegradation of nanomaterials from composites of poly(3-hydroxybutyrate) and chitosan

A complex of structure-sensitive methods of morphology analysis was applied to study film materials obtained from blends of poly(3-hydroxybutyrate) (PHB) and chitosan (CHT) by pouring from a solution, and nonwoven fibrous materials obtained by the method of electrospinning (ES). It was found that with the addition of CHT to PHB, a heterophase system with a nonequilibrium stressed structure at the interface was formed. This system, if undergone accelerated oxidation and hydrolysis, contributed to the intensification of the growth of microorganisms. On the other hand, the antimicrobial properties of CHT led to inhibition of the biodegradation process. Nonwoven nanofiber materials, since having a large specific surface area of contact with an aggressive agent, demonstrated an increased ability to be thermo-oxidative and for biological degradation in comparison with film materials. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Film Materials Based on Polyethylene with Silicon Nanoparticles and Silicon Carbide

Abstract: In this research and development, the extrusion method was used to obtain polyethylene films containing 0.1–1.5 wt % n-SiC and n-Si nanoparticles obtained by the plasma chemical method. Using the spectral analysis method, it was found that the films obtained absorb UV radiation in the range of 200–400 nm, which is harmful to organic matter. The method of X-ray structural analysis was used to determine the average size of particles and the quality of their dispersion in the films. Differential scanning calorimetry and physicomechanical tests have shown that nanoparticles do not affect the formation of the internal structure of the polyethylene (PE) matrix. The degree of crystallinity, melting point, and crystallization point remain unchanged. The properties of the surface of the films, studied by tribological and triboelectric methods and determination of the contact angle, remain constant and do not differ from the properties of PE films with a nanoparticle content from 0.1 to 1%. At 1.5% nSiC content, a change in the surface microrelief is diagnosed, leading to a small increase in the film friction coefficient. The polyethylene films filled with n-SiC and n-Si obtained in this work are recommended for use as UV protective coatings for various purposes. © 2021, Pleiades Publishing, Ltd

Aggressive impacts affecting the biodegradable ultrathin fibers based on poly(3-hydroxybutyrate), polylactide and their blends: Water sorption, hydrolysis and ozonolysis

Ultrathin electrospun fibers of pristine biopolyesters, poly(3-hydroxybutyrate) (PHB) and polylactic acid (PLA), as well as their blends, have been obtained and then explored after exposure to hydrolytic (phosphate buffer) and oxidative (ozone) media. All the fibers were obtained from a co-solvent, chloroform, by solution-mode electrospinning. The structure, morphology, and segmental dynamic behavior of the fibers have been determined by optical microscopy, SEM, ESR, and others. The isotherms of water absorption have been obtained and the deviation from linearity (the Henry low) was analyzed by the simplified model. For PHB-PLA fibers, the loss weight increments as the reaction on hydrolysis are symbate to water absorption capacity. It was shown that the ozonolysis of blend fibrils has a two-stage character which is typical for O3 consumption, namely, the pendant group’s oxidation and the autodegradation of polymer molecules with chain rupturing. The first stage of ozonolysis has a quasi-zero-order reaction. A subsequent second reaction stage comprising the back-bone destruction has a reaction order that differs from the zero order. The fibrous blend PLA/PHB ratio affects the rate of hydrolysis and ozonolysis so that the fibers with prevalent content of PLA display poor resistance to degradation in aqueous and gaseous media. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Biocompatibility and Bioresorption of 3D-Printed Polylactide and Polyglycolide Tissue Membranes

We studied biocompatibility and bioresorption of 3D-printed polylactide and polyglycolide tissue membranes. Ultrasound microscopy and histological examination showed that membranes fabricated of a copolymer of lactic and glycolic acids in a mass ratio of 1:9 are bioresorbed and have good biocompatibility with soft tissues (connective tissue, adipose tissue, and epithelium). An important feature of the copolymer membranes, which differs them from pure polylactide membranes, is the formation of a thin fibrous capsule that did not interfere its destruction by the mechanism of hydrolytic resorption. © 2021, Springer Science+Business Media, LLC, part of Springer Nature