Patrick Knaack
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View article: Photoinduced liberation of a phosphazene superbase as an initiator for oxa-Michael addition reactions
Photoinduced liberation of a phosphazene superbase as an initiator for oxa-Michael addition reactions Open
We describe herein the facile preparation and characterization of new photobase generators based on carboxylate-functionalized chromophores. They pair high wavelength absorption with the liberation of an extremely strong phosphazene superb…
View article: Investigation of Lewis photobase-catalysed oxa-Michael addition for hot lithography
Investigation of Lewis photobase-catalysed oxa-Michael addition for hot lithography Open
A set of Lewis-type photobase generators was synthesized and their ability to catalyze an oxa-Michael model reaction was compared. The best performing photobase generator was then used 3D-printing setups to produce objects with excellent r…
View article: Insights into the bulk kinetics of a 2K radical polymerization system based on the copper catalyzed cleavage of diboranes and its perspectives
Insights into the bulk kinetics of a 2K radical polymerization system based on the copper catalyzed cleavage of diboranes and its perspectives Open
This work explores the potential of a new two-component radical polymerization system with innovative analytical methods such as rheology/IR measurements during bulk polymerization.
View article: Monitoring the imidization reaction of polyimide thin films using an in-situ LIBS approach
Monitoring the imidization reaction of polyimide thin films using an in-situ LIBS approach Open
High-performance polymers like polyimides are well known for their outstanding chemical and physical properties and play an important role in high-demanding applications like automotive, aerospace, medical, etc. Polyimide thin films are es…
View article: Color-Stable Formulations for 3D-Photoprintable Dental Materials
Color-Stable Formulations for 3D-Photoprintable Dental Materials Open
Color stability is crucial for dental materials to ensure they perfectly match a patient’s tooth color. This is particularly challenging in photoresist-based additive manufacturing. Although some studies have addressed this issue, the exac…
View article: Examining differences in the uptake of corrosive gases in polymer films and its dependence on temperature and relative humidity using a novel procedure combining sample weathering and LA-ICP-MS analysis
Examining differences in the uptake of corrosive gases in polymer films and its dependence on temperature and relative humidity using a novel procedure combining sample weathering and LA-ICP-MS analysis Open
In polymer coating applications for technological products exposed to harsh environmental operating conditions, it is essential to provide and extend the protection capability of the coating material against corrosive gases, such as hydrog…
View article: Photo‐induced catalytic poly‐trimerization of polyisocyanurates
Photo‐induced catalytic poly‐trimerization of polyisocyanurates Open
Radiation curing is an excellent option for the economical implementation of coatings while simultaneously producing technically advanced products. Nevertheless, the number of materials used is mainly limited to pure (meth)acrylate and epo…
View article: Boron–boron bonds: boldly breaking boundaries towards amine- and peroxide-free 2K radical polymerization
Boron–boron bonds: boldly breaking boundaries towards amine- and peroxide-free 2K radical polymerization Open
Free radical polymerization (FRP) is one of the most important tools for the production of polymer materials.
View article: Novel thermal initiator systems for radical induced cationic frontal polymerization
Novel thermal initiator systems for radical induced cationic frontal polymerization Open
Frontal polymerization is an extremely efficient and rapid method for producing bulk polymers, characterized by a self-sustaining curing front that propagates throughout the resin.
View article: Contents list
Contents list Open
The home for the most innovative and exciting polymer chemistry, with an emphasis on polymer synthesis and applications thereof rsc.li/polymersThe Royal Society of Chemistry is the world's leading chemistry community.Through our high impac…
View article: Group transfer polymerization in bulk methacrylates
Group transfer polymerization in bulk methacrylates Open
Group transfer polymerization (GTP) is a polymerization method developed to obtain targeted (meth)acrylic polymers in solution at ambient temperatures. In this work, it is employed with methacrylic monomers to obtain low Ð polymers in bulk…
View article: Evaluation of Sulfonium Borate Initiators for Cationic Photopolymerization and Their Application in Hot Lithography
Evaluation of Sulfonium Borate Initiators for Cationic Photopolymerization and Their Application in Hot Lithography Open
Sulfonium hexafluorophosphates and perfluorinated tetraphenylborates are well established initiators in the field of cationic photopolymerization and have already been applied in 3D-printing at elevated temperatures, named hot lithography.…
View article: Additive manufacturing of high-performance polycyanurates <i>via</i> photo-induced catalytic poly-trimerization
Additive manufacturing of high-performance polycyanurates <i>via</i> photo-induced catalytic poly-trimerization Open
Investigation of a cyanate ester based formulation and stereolithography-based additive manufacturing via Hot Lithography to produce polycyanurates with a glass transition temperature of 336 °C without any additives.
View article: Iodonium Borate Initiators for Cationic Photopolymerization and Their Application in Radical-Induced Cationic Frontal Polymerization
Iodonium Borate Initiators for Cationic Photopolymerization and Their Application in Radical-Induced Cationic Frontal Polymerization Open
Iodonium antimonates and borates are well established initiators in the field of cationic photopolymerization and preferred substances for radical-induced cationic frontal polymerization (RICFP). Extensive research in the fields of ionic l…
View article: Cationic photopolymerization of cyclic esters at elevated temperatures and their application in hot lithography
Cationic photopolymerization of cyclic esters at elevated temperatures and their application in hot lithography Open
The 3D printing of polyesters is most commonly performed using polylactide filaments for material extrusion (formerly known as fused‐deposition modelling) or by introducing methacrylate end‐groups to polyesters, which can be polymerized by…
View article: Photo-chemically induced polycondensation of a pure phenolic resin for additive manufacturing
Photo-chemically induced polycondensation of a pure phenolic resin for additive manufacturing Open
Additive manufacturing of phenolic resins as a proof-of-concept for the first photo-chemical induced polycondensation by Hot Lithography. Through the dual use of a photoacidgenerator, the first pure 3D printing of Bakelite © is investigate…
View article: A systematic study of temperature‐dependent cationic photopolymerization of cyclic esters
A systematic study of temperature‐dependent cationic photopolymerization of cyclic esters Open
The polymerization of cyclic esters to form polyesters is a thoroughly investigated topic and can be performed via anionic, cationic or metal‐mediated techniques. While there have been attempts to apply light‐induced on‐demand initiation t…
View article: Evaluation of suitable onium tetrafluoroborates for cationic polymerization of epoxides
Evaluation of suitable onium tetrafluoroborates for cationic polymerization of epoxides Open
Epoxides are frequently used in coatings due to their great adhesion to most materials, high resistance towards chemicals and well‐defined material properties. Onium salts such as iodonium and sulfonium salts are one of the most widespread…
View article: Solvent-Free Ultrasonic Dispersion of Nanofillers in Epoxy Matrix
Solvent-Free Ultrasonic Dispersion of Nanofillers in Epoxy Matrix Open
Dispersion of carbon nanotubes and carbon nanofibers is a crucial processing step in the production of polymer-based nanocomposites and poses a great challenge due to the tendency of nanofillers to agglomerate. One of the most effective me…
View article: Radical-induced cationic frontal polymerisation for prepreg technology
Radical-induced cationic frontal polymerisation for prepreg technology Open
In this study, a new type of prepreg technology has been established using a dual curing system consisting of 1,6-hexanediol diacrylate (HDDA) and frontally polymerisable components based on the epoxide resin. The study of the polymerisati…
View article: Novel synthesis routes for the preparation of low toxic vinyl ester and vinyl carbonate monomers
Novel synthesis routes for the preparation of low toxic vinyl ester and vinyl carbonate monomers Open
UV curing of photopolymerizable monomers, like (meth)acrylates, has been utilized for coatings for more than half a century and more recently in further developed areas such as tissue engineering. However, these monomers have major disadva…
View article: UV-Induced Cationic Ring-Opening Polymerization of 2-Oxazolines for Hot Lithography
UV-Induced Cationic Ring-Opening Polymerization of 2-Oxazolines for Hot Lithography Open
The cationic ring-opening polymerization (CROP) of 2-oxazolines gives polymers with unique characteristics arising from its polyamide backbones and structural versatility. Up to now, poly(2-oxazoline)s were obtained by classical thermal po…
View article: Biocompatible photoinitiators based on poly‐α‐ketoesters
Biocompatible photoinitiators based on poly‐α‐ketoesters Open
Die Photopolymerisation von (Meth) acrylat-basierten Formulierungen hat sich aufgrund der hohen Energieeffizienz und niedrigen Aushärtungszeiten dieser Technologie für viele Branchen zu einer weit verbreiteten Methode entwickelt. Verschied…
View article: Microstructural study of epoxy-based thermosets prepared by “classical” and cationic frontal polymerization
Microstructural study of epoxy-based thermosets prepared by “classical” and cationic frontal polymerization Open
Epoxides prepared by cationic frontal polymerization have a greater reduced void fraction than “classically” cured samples revealing free-volume consequences of waves.
View article: Radical induced cationic frontal polymerization in thin layers
Radical induced cationic frontal polymerization in thin layers Open
Radical induced cationic frontal polymerization (FP) is a technique that allows the curing of huge epoxy parts (e.g., rotors of generators and construction composites), as well as parts with < 1 mm, within minutes instead of hours to days …
View article: Novel photoacid generators for cationic photopolymerization
Novel photoacid generators for cationic photopolymerization Open
Novel cationic photoinitiators based on the non-nucleophilic [Al(OC(CF3)3)4]− anion were prepared and their high efficiency was presented in comparison to benchmark systems.
View article: Rapid formation of regulated methacrylate networks yielding tough materials for lithography-based 3D printing
Rapid formation of regulated methacrylate networks yielding tough materials for lithography-based 3D printing Open
Vinyl sulfone esters are described as a new class of AFCT reagents for methacrylate-based photopolymerization without the drawback of retardation but good regulation of network architecture. Resulting materials show low shrinkage stress an…