Potential uses of N-methylmorpholine N-oxide for the treatment of agricultural waste biomass

Lignocellulosic fibers have been used in polymer composites for a long time but their treatment process is still challenging due to insufficient efficiency and environmental impact. This research analyses the influence of N-methylmorpholine N-oxide (NMMO) on the structure and properties of three types of lignocellulosic fibers â sweet clover (SCS), buckwheat (BS) and rapeseed straws (RS). The fibers were treated with an NMMO solution at 90 °C for different periods of time (80 min, 180 min, 300 min and 30 h). It was detected that after treatment in a dilute NMMO solution, non-cellulosic substances were removed, the morphology and aspect ratio were affected and the fibers were characterized by higher thermal stability. However, the results show that before using NMMO for the production of microfibers, additional research on the pretreatment process will be necessary because an insufficient aspect ratio value and surface morphology were obtained. The current research shows that it is not economically feasible to process fibers using NMMO for the production of reinforcement for polymer composites

Modified Silyl-Terminated Polyether Polymer Blends with Bisphenol a Diglycidyl Ether Epoxy for Adhesive Applications

Epoxy resins have been used successfully as adhesives for many years. Despite many advantages of epoxy resins like high strength, chemical and heat resistance, in many applications they lack flexibility. During service under dynamic stress and variable environment this may lead to cracking and even failure of the adhesive joint. To improve epoxy resin adhesive performance they can be modified with other polymers. In this work modified silyl-terminated polyether polymer (MS Polymer) was used as elastic matrix material in various mixing ratio with epoxy resin. In the MS Polymer/epoxy blend A component consists from MS Polymer, amine catalyst, aminosilane and additional fillers. B component is based on bisphenol A diglycidyl ether (DGEBPA) epoxy resin with tin catalyst, water and fillers. When epoxy resin is mixed together with MS Polymer at the right ratio they form heterogenic matrix/domain structure which consists of the epoxy domains functioning as hard segments in elastic MS Polymer matrix [1]. When A and B components are mixed together, curing happens by epoxy reacting with amine catalyst, at the same time MS Polymer reacting with water. Aminosilane links MS Polymer with epoxy. Tensile stress-strain characteristics according to DIN 53504 were determined by using Zwick/Roell Z010 universal testing machine. Fracture surfaces of brittle-broken test specimens were observed by using Mira/LMU field emission scanning electron microscope (TESCAN a.s.)

Rheological, Mechanical and Adhesion Properties of Two Component Adhesive based on Modified Silyl-Terminated Polyether Polymer and Epoxy Resin

Today an increasing interest in two component adhesive products can be sensed in the market. The driving force requesting more specific adhesive materials is automotive industry for bonding of light-weight structures or challenging designs. These requirements from industry make to seek for new raw material types to formulate adhesive systems with higher strength, broad superior adhesion spectrum and other demanding properties. The combination of epoxy resin with modified silyl-terminated polyether polymer (MS Polymer) is supposed to deliver a two component adhesive that shows superior strength compared to pure MS Polymer based adhesives, while combining all the other positive features from both polymer resin types. In two component adhesive formulation MS Polymer and epoxy hardener are main ingredients of one component and epoxy, MS Polymer catalyst and water are main ingredients of other component. Depending on the amount of methoxysilyl groups various MS Polymer types, namely, di-functional MS Polymers (DMS) and tri-functional MS Polymers (TMS), were used. Rheological characteristics were measured by using Bohlin CVO 100 rheometer. Instrument was equipped with 20 mm diameter spindle in plate-plate geometry with gap size 1000 m. Tests at 23 oC were performed in oscillatory shear mode at frequency 1.5 Hz and strain 0.15. Dynamic storage G’ and loss moduli G” were recorded as functions of the reaction time. Adhesive and tensile stress-strain characteristics were determined by using Zwick/Roell Z010 universal testing machine. Tensile tests were made according to DIN 53504. Lap shear tests were made according to EN 1465. Samples were tested after 1, 7, 14, 21 and 28 days of curing