scholarly journals Functionalized Biodegradable Polymers via Termination of Ring-Opening Polymerization by Acyl Chlorides

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 868
Author(s):  
Ilya Nifant’ev ◽  
Andrey Shlyakhtin ◽  
Vladimir Bagrov ◽  
Evgeny Shaputkin ◽  
Alexander Tavtorkin ◽  
...  

Aliphatic polyesters are an important class of polymeric materials for biomedical applications due to their versatile and tunable chemistry, biocompatibility and biodegradability. A capability of direct bonding with biomedically significant molecules, provided by the presence of the reactive end functional groups (FGs), is highly desirable for prospective polymers. Among FGs, N-hydroxysuccinimidyl activated ester group (NHS) and maleimide fragment (MI) provide efficient covalent bonding with –NH– and –SH containing compounds. In our study, we found that NHS- and MI-derived acyl chlorides efficiently terminate living ring-opening polymerization of ε-caprolactone, L-lactide, ethyl ethylene phosphonate and ethyl ethylene phosphate, catalyzed by 2,6-di-tert-butyl-4-methylphenoxy magnesium complex, with a formation of NHS- and MI-functionalized polymers at a high yields. Reactivity of these polymers towards amine- and thiol-containing model substrates in organic and aqueous media was also studied.

2017 ◽  
Vol 2 (4) ◽  
Author(s):  
Iuliana Cota

AbstractBiodegradable polymers represent a class of particularly useful materials for many biomedical and pharmaceutical applications. Among these types of polyesters, poly(ε-caprolactone) and polylactides are considered very promising for controlled drug delivery devices. These polymers are mainly produced by ring-opening polymerization of their respective cyclic esters, since this method allows a strict control of the molecular parameters (molecular weight and distribution) of the obtained polymers. The most widely used catalysts for ring-opening polymerization of cyclic esters are tin- and aluminium-based organometalliccomplexes; however since the contamination of the aliphatic polyesters by potentially toxic metallic residues is particularly of concern for biomedical applications, the possibility of replacing organometallic initiators by novel less toxic or more efficient organometallic complexes has been intensively studied. Thus, in the recent years, the use of highly reactive rare earth initiators/catalysts leading to lower polymer contamination has been developed. The use of rare earth complexes is considered a valuable strategy to decrease the polyester contamination by metallic residues and represents an attractive alternative to traditional organometallic complexes.


2020 ◽  
Author(s):  
Nathaniel Park ◽  
Dmitry Yu. Zubarev ◽  
James L. Hedrick ◽  
Vivien Kiyek ◽  
Christiaan Corbet ◽  
...  

The convergence of artificial intelligence and machine learning with material science holds significant promise to rapidly accelerate development timelines of new high-performance polymeric materials. Within this context, we report an inverse design strategy for polycarbonate and polyester discovery based on a recommendation system that proposes polymerization experiments that are likely to produce materials with targeted properties. Following recommendations of the system driven by the historical ring-opening polymerization results, we carried out experiments targeting specific ranges of monomer conversion and dispersity of the polymers obtained from cyclic lactones and carbonates. The results of the experiments were in close agreement with the recommendation targets with few false negatives or positives obtained for each class.<br>


2019 ◽  
Vol 3 (2) ◽  
pp. 112-119
Author(s):  
Jesús Miguel Contreras Ramírez ◽  
Dimas Medina ◽  
Francisco López-Carrasquero ◽  
Ricardo Rafael Contreras

Background: The synthesis of the aliphatic polyesters obtained by the ring opening polymerization has been achieved using as initiators a large amount of organometallic compounds derivative from: Alkali metals, alkaline earth metals, transition metals and lanthanide metals. Of all these compounds, the lanthanide derivatives have acquired great importance in the synthesis of aliphatic polyesters, since these show a greater catalytic activity and also can provide polymer with characteristics that will be very useful in the design of biomaterials. Objective: It was proposed the synthesis of poly(L-lactida) (PL-LA) through a ring opening polymerization process of L-lactide initiated with samarium(III) acetate (Sm(OAc)3) under solvent-free melt conditions. The influence of different parameters of reaction, such as temperature, time, molar ratio monomer to initiator, on typical variables of polymers, e.g., conversion, dispersity, and molar mass, were analyzed. Methods: All polymerizations were carried out under solvent-free melt conditions in ampoules-like flasks, equipped with a magnetic stirrer. The obtained polyesters were characterized by size exclusion chromatography (SEC) and 1H-NMR. Results: The Sm(OAc)3 induces the polymerization of L-LA at high conversion, and produce polyesters with number-average molecular weights of 1.00 x 103 to 30.00 x 103 Dalton. The 1H-NMR analysis indicates a typical polymerization mechanism of coordination-insertion, with a breakdown of the acyl-oxygen bond of the L-LA. Conclusion: Sm(OAc)3 was an effective initiator for the ring-opening polymerization of L-LA. SEC chromatography showed that, at high temperatures and prolonged reaction times, the molar mass of the polyester decreases, which is associated with the transesterification collateral reactions that occur during the polymerization process.


2020 ◽  
Vol 49 (14) ◽  
pp. 4737-4834 ◽  
Author(s):  
Alicia Rasines Mazo ◽  
Stephanie Allison-Logan ◽  
Fatemeh Karimi ◽  
Nicholas Jun-An Chan ◽  
Wenlian Qiu ◽  
...  

This review provides a comprehensive overview of the latest advances in the synthesis, architectural design and biomedical applications of polypeptides and their hybrids.


2020 ◽  
Vol 04 ◽  
Author(s):  
Manu Singhai ◽  
Sankha Bhattacharya

Abstract:: Polysarcosine (psar) is a non-ionic hydrophilic polypeptoid with numerous biologically relevant properties. Polysarcosine is poly (n-methylated glycine) and has been reported first by wesley and co-workers in the 1920s. Polysarcosine was first synthesized via ring-opening polymerization (rop) of sarcosine n-carboxyanhydride, using high-vacuum techniques. Overall, findings highlight the potential of poly(sarcosine) as an alternative corona-forming polymer to poly (ethylene glycol)-based analogues of (polymerization-induced self-assembly) pisa assemblies for use in various pharmaceutical and biomedical applications. Numerous studies suggested that such polypeptoids hold enormous potential for many biomedical applications, including protein delivery, colloidal stabilization, and nanomedicine.


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