Low Molecular Weight Poly Research Articles

Poly(glycidyl azide) as Photo-Crosslinker for Polymers.

Crosslinking polymers to form networks is a universal and routinely applied strategy to improve their stability and endow them with solvent resistance, adhesion properties, etc. However, the chemical crosslinking of common commercial polymers, especially for those without functional groups, cannot be achieved readily. In this study, we utilized low-molecular weight poly(glycidyl azide) (GAP) as polymeric crosslinkers to crosslink various commercial polymers via simple ultraviolet light irradiation. The azide groups were shown to decompose upon photo-irradiation and be converted to highly reactive nitrene species, which are able to insert into carbon-hydrogen bonds and thus crosslink the polymeric matrices. This strategy was demonstrated successfully in several commercial polymers. In particular, it was found that the crosslinking is highly localized, which could endow the polymeric matrices with a decent degree of crosslinking without significantly influencing other properties, suggesting a novel and robust method to crosslink polymeric materials.

Direct encapsulation of biomolecules in semi-permeable microcapsules produced with double-emulsions.

Compartmentalization can serve different purposes such as the protection of biological active substances from the environment, or the creation of a unique combination of biomolecules for diagnostic, therapeutic, or other bioengineering applications. We present a method for direct encapsulation of molecules in biocompatible and semi-permeable microcapsules made from low-molecular weight poly(ethylene glycol) diacrylate (PEG-DA 258). Microcapsules are produced using a non-planar PDMS microfluidic chip allowing for one-step production of water-in-PEG-DA 258-in-water double-emulsions, which are polymerized with UV light into a poly-PEG-DA 258 shell. Semi-permeable microcapsules are obtained by adding an inert solvent to the PEG-DA 258. Due to the favorable hydrophilicity of poly-PEG-DA 258, proteins do not adsorb to the capsule shell, and we demonstrate the direct encapsulation of enzymes, which can also be dried in the capsules to preserve activity. Finally, we leverage capsule permeability for the implementation of a two-layer communication cascade using compartmentalized DNA strand displacement reactions. This work presents the direct encapsulation of active biomolecules in semi-permeable microcapsules, and we expect our platform to facilitate the development of artificial cells and generating encapsulated diagnostics or therapeutics.

Development of 3D-printed vaginal devices containing metronidazole for alternative bacterial vaginosis treatment

Bacterial vaginosis (BV) is an abnormal condition caused by the change of microbiota in the vagina. One of the most common bacteria found in the case of BV is Gardnerella vaginalis, which is categorised as anaerobic facultative bacteria. Currently, the available treatment for BV is the use of antibiotics, such as metronidazole (MTZ), in topical and oral dosage forms. The limitation of the currently available treatment is that multiple administration is required and thus, the patient needs to apply the drug frequently to maintain the drug efficacy. To address these limitations, this research proposed prolonged delivery of MTZ in the form of intravaginal devices made from biodegradable and biocompatible polymers. Semi-solid extrusion (SSE) 3D printing was used to prepare the intravaginal devices. The ratio of high and low molecular weight poly(caprolactone) (PCL) was varied to evaluate the effect of polymer composition on the drug release. The versatility of SSE 3D printer was used to print the intravaginal devices into two different shapes (meshes and discs) and containing two different polymer layers made from PCL and a copolymer of methyl vinyl ether and maleic anhydride (Gantrez™-AN119), which provided mucoadhesive properties. Indeed, this layer made from Gantrez™-AN119 increased ca. 5 times the mucoadhesive properties of the final 3D-printed devices (from 0.52 to 2.57 N). Furthermore, MTZ was homogenously dispersed within the polymer matrix as evidenced by scanning electron microscopy analysis. Additionally, in vitro drug release, and antibacterial activity of the MTZ-loaded intravaginal devices were evaluated. Disc formulations were able to sustain the release of MTZ for 72 h for formulations containing 70/30 and 60/40 ratio of high molecular weight/low molecular weight PCL. On the other hand, the discs containing a 50/50 ratio of high molecular weight/low molecular weight PCL showed up to 9 days of release. However, no significant differences in the MTZ release from the MTZ-loaded meshes (60/40 and 50/50 ratio of high molecular weight/low molecular weight PCL) were found after 24 h. The results showed that the different ratios of high and low molecular weight PCL did not significantly affect the MTZ release. However, the shape of the devices did influence the release of MTZ, showing that larger surface area of the meshes provided a faster MTZ release. Moreover, MTZ loaded 3D-printed discs (5% w/w) were capable of inhibiting the growth of Gardnerella vaginalis. These materials showed clear antimicrobial properties, exhibiting a zone of inhibition of 19.0 ± 1.3 mm. Based on these findings, the manufactured represent a valuable alternative approach to the current available treatment, as they were able to provide sustained release of MTZ, reducing the frequency of administration and thus improving patient compliance.

Enhanced crystallization of poly(lactic acid) bioplastics by a green and facile approach using liquid poly(ethylene glycol)

AbstractPolylactic acid (PLA) bioplastics have attracted increasing attention from both academic and industrial researchers due to their biomass‐derived nature and low toxicity for the human body and environment. A major drawback of PLA is slow crystallization during processing, which considerably limits its commercial applications. In this study, a simple and low‐cost approach involving the addition of eco‐friendly low molecular weight poly(ethylene glycol) (PEG; 400 g/mole) as a green solvent was developed to enhance the PLA crystallization process. Differential scanning calorimetry and polarized optical microscopy data revealed that the introduction of PEG into PLA considerably increased the PLA crystallization rate. In particular, the isothermal crystallization rate of a system with a PLA/PEG mass ratio of 70/30 was more than seven times greater than that of neat PLA. In addition, the miscibility, thermal properties, and microstructures of various PLA/PEG blends were determined. A substantial reduction in the equilibrium melting temperature of PLA after PEG addition confirmed that these polymer blends were thermodynamically miscible in the melt, which strongly influenced the PLA crystallization rate. Furthermore, the addition of PEG increased the regularity of PLA crystals and induced the formation of ring‐banded PLA spherulites with periodic twisted lamellae.

The Incorporation of Low-Molecular Weight Poly(Mannitol Sebacate)s on PLA Electrospun Fibers: Effects on the Mechanical Properties and Surface Chemistry.

We offer a report on the synthesis of low-molecular weight biobased poly(mannitol sebacate) (PMS) and its functionalization with acrylate groups (PMSAc). These synthesized polyesters were blended at a low level (10 wt%) with poly (lactic acid) PLA to prepare aligned fibers by electrospinning, coupled with a rotatory collector. The obtained fibers were extensively studied by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and wide-angle X-ray diffraction (WAXS), employing synchrotron radiation. The incorporation of the PMSs on the PLA fibers did not significantly affect the fiber diameters, whereas the alignment was almost maintained. The crystallinity and thermal properties were also slightly modified with the addition of PMSs, and an increase in the degree of crystallinity and in the glass transition temperature of the blend compared to PLA was observed. Remarkably, the PLA/PMSs fibers were more ductile due to the elastomeric character of PMS, with higher values of elongation at break and tensile strengths, and a smaller Young modulus in comparison with the PLA fibers. These modifications of the properties were more noticeable in the case of the acrylated PMS, which also provided readily available functional groups at the surface for further chemical reactions, such as the Michael addition or crosslinking processes.

Complicated Structure Change during Capillary Extrusion of Binary Blends of Polycarbonate and Poly(methyl methacrylate).

The effects of pressure and shear rate on the miscibility of binary blends comprising bisphenol-A polycarbonate (PC) and low molecular weight poly(methyl methacrylate) (PMMA) were investigated using a capillary rheometer. Both pressure and shear rate affected the miscibility. The examination of an extruded strand of the blend provided information about the cause of the phase change. Under high pressure, pressure-induced demixing occurred at temperatures below the lower critical solution temperature (LCST) of the blend. Consequently, the extruded strand became opaque throughout. During shear-induced mixing/demixing, a part of the strand became opaque because of the distribution of the shear rate in the strand. For example, during shear-induced demixing, only the exterior of the strand, i.e., the high shear rate region, became opaque. Above the LCST, shear-induced mixing occurred, and only the center region of the strand became opaque.

A simple low-cost method to prepare gel electrolytes incorporating graphene oxide with increased ionic conductivity and electrochemical stability

It has been reported that the existence of graphene oxide (GO) provides a fast-conducting pathway, promoting ionic conductivity in solid polymer electrolytes. However, the preparation of gel polymer electrolytes with GO has been less discussed. In addition, gel polymer electrolytes are usually prepared by adding polymers to organic solvent-based electrolyte solutions. In this study, we propose a facile method for preparing composite gel polymer electrolytes using gelators in low molecular weight (exhibited the liquid state) poly(ethylene glycol) (PEG)-based electrolytes. Mixing GO in PEG-based electrolytes results in precipitation due to significant aggregation of GO. However, PEG/GO composite gel electrolytes are obtained with an inexpensive organogelator, 1,3:2,4-dibenzylidene-d-sorbitol (DBS). The DBS gels entrap the GO and prevent its aggregation. The prepared composite gel electrolytes with GO show higher ionic conductivity and a wider electrochemical stability window, indicating that these electrolytes would be suitable for electrochemical devices.

Controlling Crystallization, Mechanical Properties and Heat Resistance of Poly(L-lactide)-b-polyethylene glycol)-b-poly(L-lactide) Bioplastic by Melt Blending with Low Molecular Weight Poly(D-lactide)/Poly(L-lactide) Mixtures

The crystallization behaviour, mechanical properties and heat resistance were determined for mixtures of poly(L-lactide)-b-polyethylene glycol-b-poly(L-lactide) (PLLA-PEG-PLLA) blended with poly(D-lactide)/poly(L-lactide) with m.w. of 6,000 g/mol (PDLA6k/PLLA6k). These blends were prepared by melt blending. PLLA-PEG-PLLA/PDLA6k/PLLA6k ratios of 90/10/0, 90/7.5/2.5, 90/5/5, 90/2.5/7.5 and 90/0/10 %wt. were investigated. PLLA-PEG-PLLA/PDLA6k and PLLA-PEG-PLLA/PLLA6k blends were also prepared for comparison. The presence of PDLA6k/PLLA6k mixture improved crystallization and heat resistance of PLLA-PEG-PLLA and this improvement was related to increased PDLA6k content. However, the 90/10/0 blend film was brittle but 90/7.5/2.5, 90/5/5, 90/2.5/7.5 and 90/0/10 blend films were not. The PLLA6k blending enhanced film flexibility. The results suggested that the PLLA-PEG-PLLA blends with controllable mechanical properties and heat resistance can be prepared by varying the PDLA6k/PLLA6k ratio for use as flexible and heat-resistant biodegradable bioplastics.

Methacrylate and Styrene Block Copolymer Synthesis by Cu‐Mediated Chain Extension of Acrylate Macroinitiator in a Semibatch Reactor

AbstractA process for the well‐controlled growth of acrylates by Cu‐mediated polymerization has been developed, with macroinitiator synthesized continuously in a copper tubular reactor and subsequently chain‐extended in a semibatch reactor without additional copper. Extending this process to methacrylates and styrene, however, has proven difficult due to a significant reduction in reaction rate. This barrier has been overcome by chain‐extending the low molecular weight (Mn of 760 g mol–1) poly(methyl acrylate) macroinitiator with methacrylates and styrene using PMDETA (N,N,N′,N″,N″‐pentamethyldiethylenetriamine) as ligand. Methyl methacrylate conversions of >80% at 70 °C and diethylene glycol methyl ether methacrylate conversions of >90% at room temperature are achieved in 4 h, with the same room temperature conditions successfully applied for controlled chain extensions with butyl methacrylate. Although styrene conversions are slightly lower (60–70%) over 4 h at 85 °C, the rates achieved are substantially higher than achieved in other studies. Hydrophobic–hydrophilic triblock structures are produced through sequential monomer feeds to the semibatch reactor, keeping total reaction time to less than 5 h. The ability to incorporate methacrylates and/or styrene into structured block polymers greatly extends the range of products that can be efficiently synthesized with low copper levels by this process.

UV assisted photo reactive polyether‐polyesteramide resin for future applications in 3D printing

AbstractAmong additive manufacturing, photocuring 3D printing technologies are very relevant because of its high printing speed and high precision. However, the limited performance of photosensitive thermoset polymers is the bottleneck for the application of photocuring 3D printing in some fields, particularly in the biomedical sector. Thus, the development of biodegradable and biocompatible materials is highly desirable and of utmost importance. In this work, a biodegradable and non‐cytotoxic thermoset polymer for photocuring 3D printing is reported. It consists of an unsaturated polyesteramide bearing phenylalanine, 2‐butene‐1,4‐diol and fumarate building blocks, which is photocured under UV irradiation using a low molecular weight poly(ethylene glycol) diacrylate as crosslinker. The main characteristics of the new thermoset are: (1) very high volumetric and mechanical integrity stabilities, comparable to that of photocured epoxides; (2) very high degradation temperature; (3) very low water absorption capacity; (4) relatively fast enzymatic degradation, reaching 16.5% after 3 months; and (5) non‐cytotoxic response in presence of epithelial cells, even when soluble molecular fragments coming from biodegradation are considered. These properties favor the future utilization of the new polyether‐polyesteramide resin in the manufacturing of more sustainable products via 3D printing methods, such as stereolithography, that uses UV sources.

3D printing nanocomposites with controllable “strength-toughness” transition: Modification of SiO2 and construction of Stereocomplex Crystallites

Modified nanoparticles are increasingly being used in the manufacture of multi-purpose polymers of high-performance. Most modifications only focus on the improvement of strength or toughness of the composite materials. These adjustments are however limited by the traditional molding method. In this paper, low molecular weight poly (d-lactic acid) (PDLA) was coated on the surface of silica dioxide (SiO2) using the green chemical method. This realized nano dispersion of SiO2 in the poly (L-lactic acid)/poly (butylene adipate terephthalate) biodegradable blend (PLLA/PBAT) and uniform distribution of Stereocomplex Crystallites (SC) in the matrix. The mechanical properties of composites were dependent on their crystallization behavior, which was influenced by the temperature of 3D printing nozzle to achieve the “strength-toughness” transition. The PDLA modified SiO2 (SiO2-PDLA) evenly nano dispersed in the composite, and it did not agglomerate even at 5 wt %. The heat resistance of the composites improved with an increase in SiO2-PDLA, attributed to the SC. At a temperature of the 3D printing nozzle of 180 °C, the tensile strength of composites was greatly enhanced by the distribution of SC and SiO2-PDLA in the composite material. At a nozzle temperature of 210 °C, the SC melted. The PDLA grafted on SiO2 can act as a low molecular weight plasticizer to improve the toughness of composites.

Membranes Prepared from Recombinant RGD-Silk Fibroin as Substrates for Human Corneal Cells.

A recombinant formulation of silk fibroin containing the arginine–glycine–aspartic acid (RGD) cell-binding motif (RGD-fibroin) offers potential advantages for the cultivation of corneal cells. Thus, we investigated the growth of corneal stromal cells and epithelial cells on surfaces created from RGD-fibroin, in comparison to the naturally occurring Bombyx mori silk fibroin. The attachment of cells was compared in the presence or absence of serum over a 90 min period and analyzed by quantification of dsDNA content. Stratification of epithelial cells on freestanding membranes was examined by confocal fluorescence microscopy and optimized through use of low molecular weight poly(ethylene glycol) (PEG; 300 Da) as a porogen, the enzyme horseradish peroxidase (HRP) as a crosslinking agent, and stromal cells grown on the opposing membrane surface. The RGD-fibroin reduced the tendency of stromal cell cultures to form clumps and encouraged the stratification of epithelial cells. PEG used in conjunction with HRP supported the fabrication of more permeable freestanding RGD-fibroin membranes, that provide an effective scaffold for stromal–epithelial co-cultures. Our studies encourage the use of RGD-fibroin for corneal cell culture. Further studies are required to confirm if the benefits of this formulation are due to changes in the expression of integrins, components of the extracellular matrix, or other events at the transcriptional level.

Sustainable lubrication: low molecular weight PTFE micro-particles as extreme pressure additives for heavy duty grease applications

Purpose The purpose of this paper is to formulate heavy-duty lithium complex grease using low molecular weight poly tetra fluoro ethylene (PTFE) micro-particles as extreme pressure (EP) additive manufactured by E-beam scissoring and ultra-high speed grinding process of pre-sintered PTFE scrap. Design/methodology/approach Lithium complex grease is formulated with PTFE micro-particles, and optimum treat rate was studied by standard bench tests by ASTM D 2266 and IP-239 for tribological properties and compared with commercially available Molybdenum Di sulphide (Moly)-based lithium complex grease. The performance of the grease was further evaluated by a cyclic load test at varying speeds and loads to simulate the operational field conditions. Findings The lithium complex PTFE grease was manufactured using PTFE micro-particles as EP additive. The PTFE micro-particles dispersed in the lithium complex grease significantly improve the anti-wear performance and load bearing properties. Further, when the product was tested under a cyclic load conditions on standard tribological bench test against commercially available Moly lithium complex grease, shows stable anti-wear properties and reduced coefficient of friction. Originality/value The low molecular weight PTFE micro-particles, manufactured in the in-house electron beam (E-beam) and ultra-high speed micronizer facility from a pre-sintered PTFE scrap has been used as EP additive for grease applications for the first time. The results on the cyclic load tests indicate significant performance improvement in retaining the anti-wear and friction properties. Thus, value addition is done in formulating superior performance grease and evaluating under cyclic load conditions similar to field operating conditions and also in creating value added additives by converting the pre-sintered PTFE scarp which is environmental hazard due to poor biodegradability, creating a cyclic economy and a sustainable concept.

Rheological analysis of heat labile poly(3-hydroxybutyrate-co-3-hydroxyvalerate):poly(ethylene glycol) blends

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHB-co-HV) has shown great promise as a sustainable and biodegradable packaging material, however, progressive embrittlement, caused by secondary crystallisation, and a poor thermal stability has limited widespread use. The addition of low molecular weight poly(ethylene glycol) (PEG) has previously been shown to reduce the rate of secondary crystallisation resulting in a more viable material. This paper aims to analyse the melt miscibility of these two polymers and to assess the effect of PEG on the thermal stability. As a result of the poor thermal stability of PHB-co-HV a modified rheological procedure is implemented to create Han plots and enable assessment of the miscibility. This approach showed PHB-co-HV and PEG to be miscible within the concentrations and molecular weights studied lending itself to the fine tuning of the properties of PHB-co-HV in order to produce the most suitable and stable packaging material. The presence of PEG was observed to increase the degradation rate of PHB-co-HV at 185 °C, however, the incorporation of PEG also enabled processing at lower temperatures significantly reducing the degradation rate and widening the narrow processing window commonly found with this polymer.

Overview of Beneficial Effects of (Poly)phenol Metabolites in the Context of Neurodegenerative Diseases on Model Organisms.

The rise of neurodegenerative diseases in an aging population is an increasing problem of health, social and economic consequences. Epidemiological and intervention studies have demonstrated that diets rich in (poly)phenols can have potent health benefits on cognitive decline and neurodegenerative diseases. Meanwhile, the role of gut microbiota is ever more evident in modulating the catabolism of (poly)phenols to dozens of low molecular weight (poly)phenol metabolites that have been identified in plasma and urine. These metabolites can reach circulation in higher concentrations than parent (poly)phenols and persist for longer periods of time. However, studies addressing their potential brain effects are still lacking. In this review, we will discuss different model organisms that have been used to study how low molecular weight (poly)phenol metabolites affect neuronal related mechanisms gathering critical insight on their potential to tackle the major hallmarks of neurodegeneration.

Biodegradable, Tissue Adhesive Polyester Blends for Safe, Complete Wound Healing.

Pressure-sensitive adhesives typically used for bandages are nonbiodegradable, inhibiting healing, and may cause an allergic reaction. Here, we investigated the effect of biodegradable copolymers with promising thermomechanical properties on wound healing for their eventual use as biodegradable, biocompatible adhesives. Blends of low molecular weight (LMW) and high molecular weight (HMW) poly(lactide-co-caprolactone) (PLCL) are investigated as tissue adhesives in comparison to a clinical control. Wounds treated with PLCL blend adhesives heal completely with similar vascularization, scarring, and inflammation indicators, yet require fewer dressing changes due to integration of the PLCL adhesive into the wound. A blend of LMW and HMW PLCL produces an adhesive material with significantly higher adhesive strength than either neat polymer. Wound adhesion is comparable to a polyurethane bandage, utilizing conventional nonbiodegradable adhesives designed for extremely strong adhesion.

Fluorinated low molecular weight poly(phenylene oxide): Synthesis, characterization, and application in epoxy resin toward improved thermal and dielectric properties

To explore the high performance epoxy resin with high thermal properties and low dielectric constant and loss for copper clad laminates (CCLs), poly(phenylene oxide) (PPO) with low molecular weight is usually used as a modifier. Toward this end, a fluorinated redistributed poly(phenylene oxide) (F-rPPO) with number-average molecular weight of 3.0 ~ 6.2 × 103 g/mol was synthesized via the redistribution reaction of commercial PPO with 4,4′-(hexafluoroisopropylidene) diphenol (BPAF) using benzoyl peroxide (BPO) as an initiator. The structure of F-rPPO was characterized by 1H NMR, 19F NMR and FT-IR, respectively. F-rPPO was employed in the modification of diglycidyl ether of bisphenol A (DGEBA)/methylhexahydrophthalic anhydride (MeHHPA) epoxy resin, and the effect of F-rPPO on the curing behaviors and resulting thermosets were investigated. The results showed that the cured EP/F-rPPO resins exhibited improved thermal and dielectric properties, as well as lower moisture absorption. At 40 phr F-rPPO (based on DGEBA), the cured EP/F-rPPO resin possessed a higher Tg of 146 ℃ and Td5% of 363 ℃ than that of 129 ℃ and 321 ℃ for the pristine epoxy resin, respectively. Moreover, EP/F-rPPO exhibited a lower moisture absorption (0.33%), dielectric constant and loss (2.69 and 0.0132 at 12 GHz) compared to the pristine epoxy resin (0.48%, 2.93 and 0.0303 at 12 GHz, respectively). This work provides an easy and effective solution to fabricate the high performance epoxy resins modified by PPO to better meet the requirement of CCLs.

Confined Crystallization of Polymers within Nanopores

Crystallization of polymeric materials under nanoscopic confinement is highly relevant for nanotechnology applications. When a polymer is confined within rigid nanoporous anodic aluminum oxide (AAO) templates, the crystallization behavior experiences dramatic changes as the pore size is reduced, including nucleation mechanism, crystal orientation, crystallization kinetics, and polymorphic transition, etc. As an experimental prerequisite, exhaustive cleaning procedures after infiltrations of polymers in AAO pores must be performed to ensure producing an ensemble of isolated polymer-filled nanopores. Layers of residual polymers on the AAO surface percolate nanopores and lead to the so-called "fractionated crystallization", i.e., multiple crystallization peaks during cooling.Because the density of isolated nanopores in a typical AAO template exceeds the density of heterogeneities in bulk polymers, the majority of nanopores will be heterogeneity-free. This means that the nucleation will proceed by surface or homogeneous nucleation. As a consequence, a very large supercooling is necessary for crystallization, and its kinetics is reduced to a first-order process that is dominated by nucleation. Self-nucleation is a powerful method to exponentially increase nucleation density. However, when the diameter of the nanopores is lower than a critical value, confinement prevents the possibility to self-nucleate the material.Because of the anisotropic nature of AAO pores, polymer crystals inside AAO also exhibit anisotropy, which is determined by thermodynamic stability and kinetic selection rules. For low molecular weight poly(ethylene oxide) (PEO) with extended chain crystals, the orientation of polymer crystals changes from the "chain perpendicular to" to the "chain parallel to" the AAO pore axis, when the diameter of AAO decreases to the contour length of the PEO, indicating the effect of thermodynamic stability. When the thermodynamic requirement is satisfied, the orientation is determined by kinetics including crystal growth direction, nucleation, and crystal growth rate. An orientation diagram has been established for the PEO/AAO system, considering the cooling condition and pore size.The interfacial polymer layer has different physical properties as compared to the bulk. In poly(l-lactic acid), the relationship between the segmental mobility of the interfacial layer and crystallization rate is established. For the investigation of polymorphic transition of poly(butane-1), the results indicate that a 12 nm interfacial layer hinders the transition of Form II to Form I. Block and random copolymers have also been infiltrated into AAO nanopores, and their crystallization behavior is analogously affected as pore size is reduced.

Rheological Behavior of Hydrogen Bonding Miscible Blend: High Molecular Weight Poly(2-vinyl pyridine) and Low Molecular Weight Poly(4-vinyl phenol)

Rheological Behavior of Hydrogen Bonding Miscible Blend: High Molecular Weight Poly(2-vinyl pyridine) and Low Molecular Weight Poly(4-vinyl phenol)

Toward an Efficient Process for the Cu(0)‐Mediated Synthesis and Chain Extension of Poly(methyl acrylate) Macroinitiator Using PMDETA as Ligand

AbstractMe6TREN (tris[2‐(dimethylamino)ethyl]amine) is commonly used in Cu(0)‐mediated polymerization of acrylates due to its ability to promote high reaction rates while maintaining excellent control of chain growth. However, its cost presents a significant barrier to commercialization. Thus, the use of PMDETA (N,N,Nʹ,Nʹʹ,Nʹʹ‐pentamethyldiethylenetriamine), a ligand that is significantly less expensive than Me6TREN but is known to reduce the polymerization rate as well as control, is explored. The continuous production of low molecular weight (MW) poly(methyl acrylate) using PMDETA ligand in a copper tubular reactor is demonstrated, with conversions >70% achieved with a residence time of 32 min at 70 °C. The resulting macroinitiator solution can be stored and chain extended with methyl acrylate (MA) to high conversion in a semibatch reactor using either PMDETA or Me6TREN as additional ligand, increasing the versatility of a newly developed process to efficiently produce block copolymers using either ligand, or a combination of the two. First results suggest that the two‐step process can also be used to chain extend the macroinitiator with methacrylates, thus extending the range of materials that can be produced.