SWST 2015 International Convention Characterization of Polymerization of Isocyanate Resin and Phenolic Resins of Different Molecular weights. Part I: morphology and structure analysis Xiaomei Liu Department of Sustainable Bioproducts Mississippi State University
Outline 1. Background 2. Materials and Methods 3. Results and Discussion 4. Conclusions 5. Further study
1. Background PF resins has the properties of good heat resistance, dimensional stability, chemical resistance. It is brittle in nature and limits its applications. PF resins contain a hydroxyl group and thus have the potential to interact with other polymers. MDI reacts easily with chemicals which contain hydroxyl group and forms polyurethane elastomer. R N=C=O + OH- R === R NHCOOR Reference:Wu, Hew-Der, Peter P. Chu, and Chen-Chi M. Ma. "Thermodynamic properties of the novolac type phenolic resin blended with poly (hydroxyl ether of bisphenol A)." Polymer 39.3 (1998): 703-709.
2. Materials and Methods Materials Phenolic resins: 90%, from Fisher Formaldehyde: 50%, from Georgia Pacific NaOH: 100%, from Fisher MDI: M20 isocyanate, from BASF During the cooking procedure, get different viscosities of A, B, D, M, W using Tube type viscometer. According to Mark Houwink Sakurada equation: Where η is the intrinsic viscosity, M is the molecular weight. α and K is the Mark-Houwink Parameters. Reference:Pilato, Louis. Phenolic resins: a century of progress. New York: Springer, 2010.
2. Materials and Methods Methods: Transmission Electron Microscope (TEM) JEOL JEM-2100 LaB6 TEM, 200 kev X-ray diffraction analysis (XRD) Ultima III Lab X-ray diffraction system (λ=0.15418 nm); 40 kv and 44 Ma; 1º /min from 5º to 90º Fourier transform infrared spectroscopy (FTIR) Spectrum Two IR Spectrometers, 20 scans Thermogravimetric Analysis (TGA) SDT Q600 V20.9 Build 20, 10.00 C/min to 1000.00 C
3. Results and Discussion FTIR Results of PF with different viscosities out of phase stretching vibration of -CH 2 - alkane OH Stretch 3389 cm -1 C=C aromatic ring C-H aliphatic Asymmetric stretch of phenolic C-C-OH FTIR comparison of dried and liquid phenolic resins with different viscosities
-NCO indicates that not all the groups of MDI have completely reacted. FTIR of co-polymer system of MDI and PF resins with different molecular weights
FTIR of MDI/PF resins system and NCO groups With the increasing of PF s molecular weights, the NCO groups becomes weaker which indicates that higher molecular weights of PF resins can promote the reaction of MDI and PF resins.
C=C aromatic ring 1633 cm -1 1513 cm -1 CH out-ofplane, isolated H 885 cm -1 Compared with the PF resins, some functions like the C=C aromatic rings in the MDI/PF polymer appears while some functions like isolated H in PF resins disappeared.
3. Results and Discussion Thermal properties In the second decomposition stage, with the molecular weights increasing, the rate becomes slower and the total weight loss rate decreases. The co-polymer of MDI+PF(W) shows the best thermal property. There are two stages of the decomposition of MDI/PF polymer while there is only one in the decomposition of PF resins. At the beginning of the decomposition, the rate is much slower of co-polymer.
The first stage is the decomposition of MDI with the break of urethane bonds and the second is the ester decomposition. And the second stage is much slower than PF(M).
TG/DTG curve of MDI/PF(A) 61.78% mass loss for the first stage and 37.81% mass loss for the second stage.
TG/DTG curve of MDI/PF(M) 63.73% mass loss for the first stage and 30.52% mass loss for the second stage.
TG/DTG curve of MDI/PF(W) 56.76% mass loss for the first stage and 42.34% mass loss for the second stage.
Conclusions Till the temperature of 320, the decomposition rate of the co-polymer is much slower than PF resins Beyond the temperature of 625, the rate of MDI/PF(w) is the slowest and slower than PF resins. The mass lost are almost the same. MDI/PF(w) shows a better thermal property.
3. Results and Discussion TEM analysis TEM figures of MDI+PF(M) and PF(M) Through TEM experiment, it is confirmed that both MDI/PF and PF resins are amorphous material.
3. Results and Discussion XRD analysis XRD patterns of MDI/PF co-polymer and PF resins There are crystalline peaks at about 30.5 and 34 2theta in all the XRD patterns of MDI/PF co-polymer. The highest molecular weight leads to the highest the degree of crystallinity.
XRD patterns of MDI+PF(M) co-polymer and PF(M) resins The crystalline peaks indicated that the co-polymer system of MDI/PF resins has higher degree of crystallinity than PF resins in the structures.
4. Conclusions According to FTIR analysis, higher molecular weights of PF resins can promote the reaction of MDI and PF resins. According to TG/DTG analysis, the co-polymer MDI and the PF resins with the highest molecular weights has the best thermal property. The co-polymer system increase the degree of the crystallinity and the highest molecular weights has the highest degree.
5. Further study Techniques of recycling isocyanate based polyurethane wastes The main purpose of this study is to deal with millions of tons of isocyanate based polyurethane wastes and get the raw materials for the co-polymer system. Mechanical property of co-polymer as wood adhesive Conduct mechanical testing of isocyanate/phenolic resins copolymerization. Wood structure design and adhesive application study for co-polymer Proper wood panel structure design for this new-kind of wood resin.