The Use of Low Field NMR and Thermal Analysis to the Wood Polymer Composite Study

Abstract

The focus of this work was to characterize the molecular dynamic of High Impact Polystyrene (HIPS -5% PB), wood -A (Vochysia divergens) and B (Erisma uncinatum) -and their composites, using solid state nuclear magnetic resonance (NMR), by measuring the proton spin-lattice relaxation time (T 1 H) using a low field NMR, and by thermal analysis as Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). DSC and TGA measurements show that both woods present the same molecular behavior. On the other hand, the spin-lattice relaxation time observed that the water is interfering in the packing and arrangements of cellulose chains due to inter and intra hydrogen molecular interactions, promoting the T 1 H values changed to high values. T 1 H shows that the sample B presents a higher rigidity than sample A. However, HIPS presents higher T 1 H values comparing to wood types. Analyzing the relaxation data for the composites, the values indicate that composites present an interaction between both components.

Analysis of wood polymer composites by two-stage pyrolysis–GC/MS

“…The combination of different wood types, chemically modified wood and various polymers results in a rather complex heterogeneous material, which cannot be dissolved and is not fusible. Thus, their analytical characterization is limited to few techniques and so far the analysis of WPCs was accomplished by using FTIR [2], low field NMR and thermal analyses [3], or to determine the location of a polymer within a WPC autoradiography was used [4].…”

Effect of modified microcrystalline cellulose on poly(3-hydroxybutyrate) molecular dynamics by proton relaxometry

“…The relaxation times determined by one exponential provide the mean T 1 H values, related to the overall behavior of the samples, which are influenced by chemical structure, molecular interactions, and polymer organization, depicting the contribution of all relaxation times. 30 It has been observed that the addition of 0.25% cellulose caused a reduction in the value of T 1 H when compared to pristine polymer. There was an increase in the molecular mobility due to the possible insertion of cellulose among the polymer chains, causing their separation.…”