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ARGET ATRP for Versatile Grafting of Cellulose Using Various Monomers
KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.ORCID-id: 0000-0002-8194-0058
KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.ORCID-id: 0000-0002-8348-2273
2009 (Engelska)Ingår i: ACS Applied Materials & Interfaces, ISSN 1944-8244, Vol. 1, nr 11, s. 2651-2659Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

In recent years, cellulose-based materials have attracted significant attention. To broaden the application areas for cellulose, polymers are often grafted to/from the surface to modify its properties. This study applies ARGET (activators regenerated by electron transfer) ATRP (atom transfer radical polymerization) when straightforwardly grafting methyl methacrylate (MMA), styrene (St), and glycidyl methacrylate (GMA) from cellulose in the form of conventional filter paper In the presence of a sacrificial initiator. The free polymer, formed from the free initiator in parallel to the grafting, was characterized by H-1 NMR and SEC, showing that sufficient control is achieved. However, the analyses also indicated that the propagation from the surface cannot be neglected compared to the propagation of the free polymer at higher targeted molecular weights, which is an assumption often made. The grafted filter papers were evaluated with FT-IR, suggesting that the amount of polymer on the surface increased with increasing monomer conversion, which the FE-SEM micrographs of the substrates also demonstrated. Water contact angle (CA) measurements implied that covering layers of PMMA and PS were formed on the cellulose substrate, making the surface hydrophobic, in spite of low DPs. The CA of the PGMA-grafted filter papers revealed that, by utilizing either aprotic or protic solvents when washing the substrates, it was possible to either preserve or hydrolyze the epoxy groups. Independent of the solvent used, all grafted filter papers were essentially colorless after the washing procedure because of the low amount of copper required when performing ARGET ATRP. Nevertheless, surface modification of cellulose via ARGET ATRP truly facilitates the manufacturing since no thorough freeze-thaw degassing procedures are required.

Ort, förlag, år, upplaga, sidor
2009. Vol. 1, nr 11, s. 2651-2659
Nyckelord [en]
ARGET ATRP, cellulose, controlled polymerization, grafting from, surface modification of cellulose, functional monomers, glycidyl, methacrylate, reducing agent, transfer radical polymerization, ring-opening polymerization, surface, modification, raft polymerization, reducing agent, methacrylate, polymers, fibers, nanoparticles, styrene
Nationell ämneskategori
Kemi
Identifikatorer
URN: urn:nbn:se:kth:diva-18979DOI: 10.1021/am900547gISI: 000272039700032Scopus ID: 2-s2.0-77951236507OAI: oai:DiVA.org:kth-18979DiVA, id: diva2:337026
Anmärkning
QC 20100525Tillgänglig från: 2010-08-05 Skapad: 2010-08-05 Senast uppdaterad: 2012-11-26Bibliografiskt granskad
Ingår i avhandling
1. ARGET ATRP as a Tool for Cellulose Modification
Öppna denna publikation i ny flik eller fönster >>ARGET ATRP as a Tool for Cellulose Modification
2012 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

The importance of finding new applications for cellulose‐based products has increased, especially to meet the demand for new environmentally friendly materials, but also since the digitalization of our society will eventually decrease the need for paper. To expand the application area of cellulose, modification to improve and/or introduce new properties can be a requisite. Thus, the focus of this study has been to achieve fundamental knowledge about polymer grafting of cellulose via well‐controlled radical polymerization.

Cellulose, in the form of filter paper, has successfully been grafted via activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) of the monomers: methyl methacrylate, styrene, and glycidyl methacrylate. The advantages of ARGET ATRP are that only a small amount of a copper catalyst is required and the reaction can be performed in limited amount of air; yet, providing for relatively well‐controlled reactions. These benefits can render ARGET ATRP an attractive method for industrial utilization.

The contact‐angle measurements of the grafted filter papers confirmed that the hydrophobicity of cellulose was significantly increased, even for shorter graft lengths. FT‐IR spectroscopy established that the amount of polymer successively increased with monomer conversion. High‐resolution FT‐IR microscopy (FT‐IRM) was proven to be a very useful technique for the analysis of cellulose substrates, displaying the spatial distribution of polymer content on cellulose fibers. The polymer was shown to be fairly homogenously distributed on the fiber.

An initiator with a reducible disulfide bond rendered cleavage of the polymer grafts possible, employing mild reaction conditions. The cleaved grafts and the free polymers – formed from a sacrificial initiator in parallel to the grafting – were shown to have similar molar masses and dispersities, confirming that the grafts can be tailored by utilizing a sacrificial initiator. Moreover, the initiator content on filter paper and microcrystalline cellulose was assessed.

A comparison between the two grafting techniques, grafting‐from cellulose via ARGET ATRP and grafting‐to cellulose via copper(I)‐catalyzed alkyne‐azide cycloaddition, was performed. To achieve a trustworthy comparison, the free polymer formed in parallel to the grafting‐from reaction was employed as the prepolymer in the grafting‐to approach, resulting in nearly identical graft length on the substrates for the two grafting methods. FT‐IRM analyses verified that under the selected conditions, the grafting‐from technique is superior to the grafting‐to approach with respect to controlling the distribution of the polymer content on the surface. The results were corroborated with X‐ray photoelectron spectroscopy.

Ort, förlag, år, upplaga, sidor
Stockholm: KTH Royal Institute of Technology, 2012. s. 62
Serie
Trita-CHE-Report, ISSN 1654-1081 ; 2012:60
Nationell ämneskategori
Polymerteknologi
Identifikatorer
urn:nbn:se:kth:diva-105762 (URN)978-91-7501-544-6 (ISBN)
Disputation
2012-12-14, K2, Teknikringen 28, KTH, Stockholm, 10:00 (Engelska)
Opponent
Handledare
Anmärkning

QC 20121126

Tillgänglig från: 2012-11-26 Skapad: 2012-11-26 Senast uppdaterad: 2012-11-26Bibliografiskt granskad

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Carlmark, AnnaMalmström, Eva

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