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Molecules (Basel, Switzerland) Jun 2018Cyclodextrin complexes of fragrances, antimicrobial agents, dyes, insecticides, UV-filters can be incorporated into polymers (packaging films, trays, containers) either... (Review)
Review
Cyclodextrin complexes of fragrances, antimicrobial agents, dyes, insecticides, UV-filters can be incorporated into polymers (packaging films, trays, containers) either to ensure the slow release or a homogeneous distribution of the complexed substances. This way the propagation of microorganisms on surface of enwrapped products is decelerated, or the product is made more attractive by slowly released fragrances, protected against UV-light-induced deterioration, oxidation, etc. Incorporating empty cyclodextrins into the packaging material an aroma barrier packaging is produced, which decelerates the loss of the aroma from the packaged food, prevents the penetration of undesired volatile pollutants from the environment, like components of exhaust gases, cigarette smoke, and reduces the migration of plasticizers, residual solvents and monomers, etc. Applying cyclodextrins in active packaging allows to preserve the quality of food and ensures a longer shelf-life for the packaged items.
Topics: Cellulose; Cyclodextrins; Food Packaging; Polymers
PubMed: 29954121
DOI: 10.3390/molecules23071556 -
The Science of the Total Environment Oct 2023Plastic pollution is a critical problem that has the potential for long-lasting impact. While all plastics eventually break down to at least some degree, they can remain... (Review)
Review
Plastic pollution is a critical problem that has the potential for long-lasting impact. While all plastics eventually break down to at least some degree, they can remain in different transition states, such as microplastics and nanoplastics, for extended periods of time before reaching complete mineralisation to non-hazardous end products. Each of the transition states represents different types of hazards, so it is critical to understand the factors driving the lifetimes of plastics within these states. To do this, we propose a framework for assessing plastic lifetimes in natural environments based on the flow of material through potentially hazardous states: macroplastic and mesoplastic, microplastic, nanoplastic and soluble products. State changes within this framework are underpinned by three key processes: fragmentation, depolymerisation, and bioassimilation, with the pathways for generation of the different plastic states, and the lifetimes within these states, varying widely for individual materials in different environments due to their dependence on polymer material type, form and properties, and environmental factors. The critical factors driving these processes can therefore appear complex, but molecular weight, crystallinity, oxygen and water diffusivity, and inherent polymer chain reactivity (including to enzymes) are key to our understanding. By analysing currently available data that take factors such as these into consideration, we have generated information on the most likely states in which a range of plastics with different environmental degradation behaviour may exist over time in natural environments. Polyethylene (PE), for example, should be expected to fragment and accumulate in the environment as microplastic and nanoplastic. Interestingly, the state-profile for the biodegradable plastic polylactic acid (PLA) is similar, albeit over shorter timeframes. PLA also likely fragments, but then the relatively slow process of abiotic depolymerisation results in accumulation of microplastic and nanoplastic. By contrast, the state-profile for the biodegradable plastic polyhydroxyalkanoate (PHA) would be expected to be very different. The bulk material is less susceptible to embrittlement and fragmentation as a primary path to biodegradation, since the rapid enzyme catalysed depolymerisation of exposed surfaces proceeds in conjunction with bioassimilation.
Topics: Biodegradable Plastics; Plastics; Microplastics; Polyesters; Polymers; Biodegradation, Environmental; Water Pollutants, Chemical
PubMed: 37348710
DOI: 10.1016/j.scitotenv.2023.165025 -
Physiological Research Oct 2016Self-organization in a polymer system appears when a balance is achieved between long-range repulsive and short-range attractive forces between the chemically different... (Review)
Review
Self-organization in a polymer system appears when a balance is achieved between long-range repulsive and short-range attractive forces between the chemically different building blocks. Block copolymers forming supramolecular assemblies in aqueous media represent materials which are extremely useful for the construction of drug delivery systems especially for cancer applications. Such formulations suppress unwanted physicochemical properties of the encapsulated drugs, modify biodistribution of the drugs towards targeted delivery into tissue of interest and allow triggered release of the active cargo. In this review, we focus on general principles of polymer selforganization in solution, phase separation in polymer systems (driven by external stimuli, especially by changes in temperature, pH, solvent change and light) and on effects of copolymer architecture on the self-assembly process.
Topics: Drug Delivery Systems; Hydrophobic and Hydrophilic Interactions; Nanoparticles; Polymers; Surface-Active Agents
PubMed: 27762583
DOI: 10.33549/physiolres.933419 -
Proceedings of the National Academy of... Apr 2023Biomolecular phase separation has emerged as an essential mechanism for cellular organization. How cells respond to environmental stimuli in a robust and sensitive...
Biomolecular phase separation has emerged as an essential mechanism for cellular organization. How cells respond to environmental stimuli in a robust and sensitive manner to build functional condensates at the proper time and location is only starting to be understood. Recently, lipid membranes have been recognized as an important regulatory center for biomolecular condensation. However, how the interplay between the phase behaviors of cellular membranes and surface biopolymers may contribute to the regulation of surface condensation remains to be elucidated. Using simulations and a mean-field theoretical model, we show that two key factors are the membrane's tendency to phase-separate and the surface polymer's ability to reorganize local membrane composition. Surface condensate forms with high sensitivity and selectivity in response to features of biopolymer when positive co-operativity is established between coupled growth of the condensate and local lipid domains. This effect relating the degree of membrane-surface polymer co-operativity and condensate property regulation is shown to be robust by different ways of tuning the co-operativity, such as varying membrane protein obstacle concentration, lipid composition, and the affinity between lipid and polymer. The general physical principle emerged from the current analysis may have implications in other biological processes and beyond.
Topics: Polymers; Cell Membrane; Membranes; Membrane Proteins; Lipids
PubMed: 37018196
DOI: 10.1073/pnas.2212516120 -
Molecules (Basel, Switzerland) May 2023With the increasing energy demand, oil is still an important fuel source worldwide. The chemical flooding process is used in petroleum engineering to increase the... (Review)
Review
With the increasing energy demand, oil is still an important fuel source worldwide. The chemical flooding process is used in petroleum engineering to increase the recovery of residual oil. As a promising enhanced oil-recovery technology, polymer flooding still faces some challenges in achieving this goal. The stability of a polymer solution is easily affected by the harsh reservoir conditions of high temperature and high salt, and the influence of the external environment such as high salinity, high valence cations, pH value, temperature and its own structure is highlighted. This article also involves the introduction of commonly used nanoparticles, whose unique properties are used to improve the performance of polymers under harsh conditions. The mechanism of nanoparticle improvement on polymer properties is discussed, that is, how the interaction between them improves the viscosity, shear stability, heat-resistance and salt-tolerant performance of the polymer. Nanoparticle-polymer fluids exhibit properties that they cannot exhibit by themselves. The positive effects of nanoparticle-polymer fluids on reducing interfacial tension and improving the wettability of reservoir rock in tertiary oil recovery are introduced, and the stability of nanoparticle-polymer fluid is described. While analyzing and evaluating the research on nanoparticle-polymer fluid, indicating the obstacles and challenges that still exist at this stage, future research work on nanoparticle-polymer fluid is proposed.
Topics: Polymers; Petroleum; Chemical Phenomena; Viscosity; Nanoparticles
PubMed: 37298805
DOI: 10.3390/molecules28114331 -
Chemical Society Reviews Jun 2024Polymer prodrugs are based on the covalent linkage of therapeutic molecules to a polymer structure which avoids the problems and limitations commonly encountered with... (Review)
Review
Polymer prodrugs are based on the covalent linkage of therapeutic molecules to a polymer structure which avoids the problems and limitations commonly encountered with traditional drug-loaded nanocarriers in which drugs are just physically entrapped (, burst release, poor drug loadings). In the past few years, reversible-deactivation radical polymerization (RDRP) techniques have been extensively used to design tailor-made polymer prodrug nanocarriers. This synthesis strategy has received a lot of attention due to the possibility of fine tuning their structural parameters (, polymer nature and macromolecular characteristics, linker nature, physico-chemical properties, functionalization, ), to achieve optimized drug delivery and therapeutic efficacy. In particular, adjusting the nature of the drug-polymer linker has enabled the easy synthesis of stimuli-responsive polymer prodrugs for efficient spatiotemporal drug release. In this context, this review article will give an overview of the different stimuli-sensitive polymer prodrug structures designed by RDRP techniques, with a strong focus on the synthesis strategies, the macromolecular architectures and in particular the drug-polymer linker, which governs the drug release kinetics and eventually the therapeutic effect. Their biological evaluations will also be discussed.
Topics: Prodrugs; Polymerization; Drug Carriers; Humans; Polymers; Nanoparticles; Drug Liberation; Free Radicals
PubMed: 38775004
DOI: 10.1039/d2cs01060g -
Molecules (Basel, Switzerland) Aug 2019Polymerization provides an efficient strategy for synthesizing macromolecules with versatile functionality [...].
Polymerization provides an efficient strategy for synthesizing macromolecules with versatile functionality [...].
Topics: Biological Products; Biosensing Techniques; Drug Delivery Systems; Food Technology; Humans; Information Storage and Retrieval; Polymerization; Polymers; Tissue Engineering; Water Purification
PubMed: 31426353
DOI: 10.3390/molecules24162976 -
International Journal of Molecular... Sep 2022Using hybrid multi-particle collision dynamics (MPCD) and a molecular dynamics (MD) method, we investigate the effect of arms and shear flow on dynamical and structural...
Using hybrid multi-particle collision dynamics (MPCD) and a molecular dynamics (MD) method, we investigate the effect of arms and shear flow on dynamical and structural properties of the comb long-chain branched (LCB) polymer with dense arms. Firstly, we analyze dynamical properties of the LCB polymer by tracking the temporal changes on the end-to-end distance of both backbones and arms as well as the orientations of the backbone in the flow-gradient plane. Simultaneously, the rotation and tumbling behaviors with stable frequencies are observed. In other words, the LCB polymer undergoes a process of periodic stretched-folded-stretched state transition and rotation, whose period is obtained by fitting temporal changes on the orientation to a periodic function. In addition, the impact induced by random and fast motions of arms and the backbone will descend as the shear rate increases. By analyzing the period of rotation behavior of LCB polymers, we find that arms have a function in keeping the LCB polymer's motion stable. Meanwhile, we find that the rotation period of the LCB polymer is mainly determined by the conformational distribution and the non-shrinkable state of the structure along the velocity-gradient direction. Secondly, structural properties are numerically characterized by the average gyration tensor of the LCB polymer. The changes in gyration are in accordance with the LCB polymer rolling when varying the shear rate. By analyzing the alignment of the LCB polymer and comparing with its linear and star counterparts, we find that the LCB polymer with very long arms, like the corresponding linear chain, has a high speed to reach its configuration expansion limit in the flow direction. However, the comb polymer with shorter arms has stronger resistance on configuration expansion against the imposed flow field. Moreover, with increasing arm length, the comb polymer in shear flow follows change from linear-polymer-like to capsule-like behavior.
Topics: Molecular Conformation; Molecular Dynamics Simulation; Polymers; Rotation
PubMed: 36232591
DOI: 10.3390/ijms231911290 -
Angewandte Chemie (International Ed. in... Sep 2022Organocatalysis has evolved into an effective complement to metal- or enzyme-based catalysis in polymerization, polymer functionalization, and depolymerization. The ease... (Review)
Review
Organocatalysis has evolved into an effective complement to metal- or enzyme-based catalysis in polymerization, polymer functionalization, and depolymerization. The ease of removal and greater sustainability of organocatalysts relative to transition-metal-based ones has spurred development in specialty applications, e.g., medical devices, drug delivery, optoelectronics. Despite this, the use of organocatalysis and other organomediated reactions in polymer chemistry is still rapidly developing, and we envisage their rapidly growing application in nascent areas such as controlled radical polymerization, additive manufacturing, and chemical recycling in the coming years. In this Review, we describe ten trending areas where we anticipate paradigm shifts resulting from novel organocatalysts and other transition-metal-free conditions. We highlight opportunities and challenges and detail how new discoveries could lead to previously inaccessible functional materials and a potentially circular plastics economy.
Topics: Catalysis; Plastics; Polymerization; Polymers
PubMed: 35700152
DOI: 10.1002/anie.202203043 -
Biomacromolecules Aug 2023Nanocellulose is emerging as a sustainable building block in materials science. Surface modification via polymer grafting has proven to be effective in tuning diverse...
Nanocellulose is emerging as a sustainable building block in materials science. Surface modification via polymer grafting has proven to be effective in tuning diverse material properties of nanocellulose, including wettability of films and the reinforcement effect in polymer matrices. Despite its widespread use in various environments, the structure of a single polymer-grafted nanocellulose remains poorly understood. Here, we investigate the morphologies of polymer-grafted CNFs at water-mica and air-mica interfaces by using all-atom molecular dynamics simulation and atomic force microscopy. We show that the morphologies of the polymer-grafted CNFs undergo a marked change in response to the surrounding environment due to variations in the conformation of the surface polymer chains. Our results provide novel insights into the molecular structure of polymer-grafted CNFs and can facilitate the design and development of innovative biomass-based nanomaterials.
Topics: Polymers; Aluminum Silicates; Nanostructures; Molecular Structure
PubMed: 37499269
DOI: 10.1021/acs.biomac.3c00530