Novel peroxide-initiating monomer with the peroxide group and the polymerizable vinyl double bond was designed and prepared through cheap industrial chemical reactants and facile synthesis. Here, one ...kind of the peroxide-initiating monomer 2-(tert-butylperoxy)ethyl methacrylate (BPEMA) prepared through three-step simple chemical reactions, using tert-butyl hydroperoxide and 2-bromoethanol as the raw ingredients, which reacted at low temperature and obtained the 2-tert-butyl peroxy ethanol, then esterified with methacryloyl chloride or isobutyryl chloride to obtain the peroxide-initiating monomer 2-(tert-butylperoxy)ethyl methacrylate(BPEMA). The analogue peroxide-initiating compound 2-(tert-butylperoxy)ethyl isobutyrate (BPEIB) was designed and obtained using the same reactions as those employed with BPEMA. The other kind of the peroxide-initiating monomer 2-hydroperoxide ethyl methacrylate (HPEMA). The purity of the three products was determined to be above 95%. Here, develop convenient and effective methods in using peroxide-initiating monomer for the in-depth study on the preparation of branched polymers.
The present study highlights a range of surface and volume extrudate patterns that can be detected during the extrusion flow of long‐chain branched polymers. Thus, four linear low‐density ...polyethylenes (LDPEs) have been extruded using a single‐screw extruder coupled to an inline optical imaging system. The selected LDPEs are selected to outline the influence of molecular weight and long‐chain branching on the types of melt flow extrusion instabilities (MFEI). Through the inline imaging system, space–time diagrams are constructed and analyzed via Fourier‐transformation using a custom moving window procedure. Based on the number of characteristic frequencies, peak broadness, and whether they are surface or volume distortions, three main MFEI types, distinct from those typically observed in linear and short‐chain branched polymers, are identified. The higher molecular weight, low long‐chain branching LDPEs exhibited all three instability types, including a special type volume instability. Independently of the molecular weight, higher long‐chain branching appeared to have a stabilizing effect on the transition sequences by suppressing volume extrudate distortions or limiting surface patters to a form of weak intensity type.
Melt flow extrusion instabilities (MFEI) in long‐chain branched polymers is a rather neglected topic in the field. In this study an intriguing array of MFEI in low‐density polyethylenes is highlighted, and the dependence of extrudate patterns on the molecular topology of the polymers is discussed.
Precipitation Polymerization (Pre-Poly) can be considered a nucleation and growth process in which complex and high molecular weight branched polymers are involved. From an experimental point of ...view, it is well-known that under Pre-Poly conditions the phase transition (nucleation) occurs in the first minutes of polymerization, and then a long growth stage is observed in which the critical nuclei simultaneously grow until reaching a highly monodisperse distribution of microspheres (characteristic mechanism of binodal decomposition). The high rate at which nucleation and growth processes usually take place when radical polymerization (extremely high polymerization rate) under Pre-Poly conditions is used, makes it very difficult to study experimentally some aspects of these processes, such as the size and concentration of critical nuclei, among others. Based on the thermodynamic principles of Pre-Poly, this analytical paper covers for the first time, to the best of our knowledge, the theoretical formulation of the distribution function of critical nuclei under Pre-Poly conditions. In addition, a simple empirical method to calculate the concentration of critical nuclei was also developed using only three global, physical experimental parameters, and good agreement was found between empirical and theoretical calculations.
Display omitted
•In precipitation polymerization nucleation is controlled by interaction parameter (χ).•The distribution function of critical nuclei vs. χ was theoretically formulated.•The concentration of critical nuclei follows a Gaussian distribution vs. χ.•An empirical method to calculate the distribution function was also developed.•Good agreement was observed between empirical and theoretical calculations.
The past decades have witnessed rapid development of lithium-based batteries. Significant research efforts have been progressively diverted from electrodes to electrolytes, particularly polymer ...electrolytes (PEs), to tackle the safety concern and promote the energy storage capability of batteries. To further increase the ionic conductivity of PEs, various branched polymers (BPs) have been rationally designed and synthesized. Compared with linear polymers, branched architectures effectively increase polymer segmental mobility, restrain crystallization, and reduce chain entanglement, thereby rendering BPs with greatly enhanced lithium transport. In this Mini Review, a diversity of BPs for PEs is summarized by scrutinizing their unique topologies and properties. Subsequently, the design principles for enhancing the physical properties, mechanical properties, and electrochemical performance of BP-based PEs (BP-PEs) are provided in which the ionic conduction is particularly examined in light of the Li+ transport mechanism. Finally, the challenges and future prospects of BP-PEs in this rapidly evolving field are outlined.
Immune response in the tumor microenvironment (TME) is an essential therapeutic factor for antitumor therapy. Herein, to improve immunostimulatory effects, photodynamic therapy (PDT) is combined with ...AZD2281 to trigger the stimulator of interferon genes (STING)‐dependent immune responses. A synthetic branched polymer‐pyropheophorbide a (Ppa) conjugate (BGSSP) is designed and developed in response to redox/cathepsin B of the TME. This conjugate with a unique structure and a large molecular weight (MW) can self‐assemble into a compact structure via hydrophilic and hydrophobic forces, inducing self‐quenching of conjugated Ppa. AZD2281 is encapsulated in BGSSP to obtain a TME‐activatable photodynamic nanoagent, AZD@BGSSP. AZD@BGSSP with a stable assembly structure accumulates effectively in tumors and enters lysosomes through endocytosis pathways. Polymer degradation, Ppa activation, and AZD2281 release are achieved after exposure of AZD@BGSSP to highly expressed cathepsin B and glutathione in tumor cells. After laser irradiation, AD2281 inhibits the repair of damaged DNA caused by ROS from PDT and promotes generation of cytosolic DNA, which activates the cGAS‐STING pathway and further induces interferons‐mediated immune responses and a long‐term immune memory effect for immunotherapy. This nanoagent opens a new door to combination PDT and immune response for anti‐cancer treatment.
Combination of a PARP inhibitor and branched biodegradable polymer‐Ppa, TME‐activatable nanoagents achieves a prominent antitumor effect by inhibiting the repair of damaged DNA and promoting generation of cytosolic DNA, activating the cGAS‐STING pathway and induing IFN‐mediated antitumor immune responses and a long‐term immune memory effect.
Cytosolic protein delivery is a prerequisite for protein‐based biotechnologies and therapeutics on intracellular targets. Polymers that can complex with proteins to form nano‐assemblies represent one ...of the most important categories of materials, because of the ease of nano‐fabrication, high protein loading efficiency, no need for purification, and maintenance of protein bioactivity. Stable protein encapsulation and efficient intracellular liberation are two critical yet opposite processes toward cytosolic delivery, and polymers that can resolve these two conflicting challenges are still lacking. Herein, hyperbranched poly(β‐amino ester) (HPAE) with backbone‐embedded phenylboronic acid (PBA) is developed to synchronize these two processes, wherein PBA enhanced protein encapsulation via nitrogen–boronate (N–B) coordination while triggered polymer degradation and protein release upon oxidation by H2O2 in cancer cells. Upon optimization of the branching degree, charge density, and PBA distribution, the best‐performing A2‐B3‐C2‐S2‐P2 is identified, which mediates robust delivery of various native proteins/peptides with distinct molecular weights (1.6–430 kDa) and isoelectric points (4.1–10.3) into cancer cells, including enzymes, toxins, antibodies, and CRISPR‐Cas9 ribonucleoproteins (RNPs). Moreover, A2‐B3‐C2‐S2‐P2 mediates effective cytosolic delivery of saporin both in vitro and in vivo to provoke remarkable anti‐tumor efficacy. Such a potent and universal platform holds transformative potentials for protein pharmaceuticals.
Reactive oxygen species (ROS)‐degradable, hyperbranched poly(β‐amino ester) (HPAE) with well‐tailored structure enables highly efficient cytosolic protein/peptide delivery into cancer cells, and it quickly degrades in response to over‐produced H2O2 to facilitate the intracellular cargo release and potentiate the protein activity.
•Branched dihydrophenazine polymer is reported as cathode material for batteries.•The electrodes showed high capacity, discharge voltage, energy and power density.•The electrochemical performances ...exceed most reported organic cathodes.•The charge storage mechanism was investigated in detail.
Organic electrode materials have exhibited good electrochemical performance in batteries, but their voltages and rate capabilities still require improvement to meet the increasing demand for batteries with high energy and power density. Herein, we design and synthesize a branched dihydrophenazine-based polymer (p-TPPZ) as a cathode material for dual-ion batteries (DIBs) through delicate molecular design. Compared with the linear dihydrophenazine-based polymer (p-DPPZ, with a theoretical capacity of 209 mAh g–1), p-TPPZ possessed a higher theoretical capacity of 233 mAh g–1 and lower highest occupied molecular orbital energy levels,which resulted in a high actual capacity (169.3 mAh g–1 at 0.5 C), an average discharge voltage of 3.65 V (vs. Li+/Li) and a high energy density (618.2 Wh kg–1, based on the cathode materials). The branched structure of p-TPPZ led to a larger specific surface area than that of p-DPPZ, which was beneficial for the electrolyte infiltration and fast ionic transport, contributing to the high power density. Due to the fast reaction kinetics, even at a power density of 23,725 W kg–1 (40 C), the energy density still reached 474.5 Wh kg–1. We also made a detailed investigation of the p-TPPZ cathode's charge storage mechanism. This work will stimulate the further molecular design to develop organic batteries with both high energy and power density.
Display omitted
A stimuli‐responsive polymeric prodrug‐based nanotheranostic system with imaging agents (cyanine5.5 and gadolinium‐chelates) and a therapeutic agent paclitaxel (PTX) is prepared via polymerization ...and conjugating chemistry. The branched polymeric PTX‐Gd‐based nanoparticles (BP‐PTX‐Gd NPs) demonstrate excellent biocompatibility, and high stability under physiological conditions, but they stimuli‐responsively degrade and release PTX rapidly in a tumor microenvironment. The in vitro behavior of NPs labeled with fluorescent dyes is effectively monitored, and the NPs display high cytotoxicity to 4T1 cells similar to free PTX by impairing the function of microtubules, downregulating anti‐apoptotic protein Bcl‐2, and upregulating the expression of Bax, cleaved caspase‐3, cleaved caspase‐9, cleaved‐PARP, and p53 proteins. Great improvement in magnetic resonance imaging (MRI) is demonstrated by these NPs, and MRI accurately maps the temporal change profile of the tumor volume after injection of NPs and the tumor treatment process is also closely correlated with the T1 values measured from MRI, demonstrating the capability of providing real‐time feedback to the chemotherapeutic treatment effectiveness. The imaging‐guided chemotherapy to the 4T1 tumor in the mice model achieves an excellent anti‐tumor effect. This stimuli‐responsive polymeric nano‐agent opens a new door for efficient breast cancer treatment under the guidance of fluorescence/MRI.
This study demonstrates a strategy to fabricate stimuli‐responsive branched polymeric prodrug‐based theranostic nanomedicine. The anticancer mechanism is studied well and the in vitro and vivo behaviors including biodistribution, retention, and anticancer efficacy can be monitored well by imaging. This stimuli‐responsive polymeric demonstrates great potential of a platform for cancer nanotheranostics.
Objectives.
Biologically active polymeric surfactants are a new promising class of macromolecules that can find application in medicine, cosmetology, and agriculture. In this study, a number of new ...biologically active amphiphilic polymers based on branched silatrane-containing polyesters and polyethers were obtained, and their surface-active properties were investigated.
Methods.
The branched polymers were represented by polyethers and polyesters, obtained respectively via the anionic polymerization of 1,2-epoxypropanol or a combination of equilibrium polycondensation and ring opening polymerization. The polymers were modified with 3-isocyanopropylsilatrane and trimethylethoxysilane to obtain the amphiphilic compounds containing silatrane groups bonded to the polymer backbone by the urethane bond. The structure of the synthesized polymer silatranes was confirmed via nuclear magnetic resonance spectroscopy and gel permeation chromatography. The surface active properties of all the copolymers obtained were investigated in connection with their obvious amphiphilicity. In particular, the formation of micelles in aqueous solutions is such a property. The critical micelle concentrations were determined by a method of quenching the fluorescence of the polymers.
Results.
It was shown that the values of the critical micelle concentrations and the hydrophilic-lipophilic balance values of polymers determined by the Griffin equation correlate well with each other. A linear relationship between the hydrophilic-lipophilic balance and the critical micelle concentrations was established. At the same time, polyether-based polymers generally showed higher critical micelle concentrations than polyester-based polymers, although the hydrophilic-lipophilic balance values for polymers of different series, but with close degrees of substitution, were close. It was found that the use of all synthesized polymers as stabilizers of direct and reverse emulsions leads to an increase in the aggregative stability of both types of emulsions. The stability of emulsions depended both on the degree of substitution of peripheral hydroxyl groups of polymers by silatranes and on the molecular weight and structure of the branched block of polymers. The stability of direct emulsions increased for all polymers, while that of inverse emulsions decreased with an increasing degree of substitution of hydroxyl groups by silatranes. The increase of the branched block molecular weight led to an increase of droplet sizes for both direct and inverse emulsions. The smallest droplet size for direct and inverse emulsions was obtained using polymers with low molecular weight branched polyester blocks as surfactants.
Conclusions.
The results obtained prove the possibility of creating polymer surfactants containing silatrane groups. By varying the structure of the polymer, its molecular weight and the degree of substitution of peripheral functional groups, it is possible to obtain surfactants with desired surface properties.
PDF
