Preparation of Novel c-6 Position Carboxyl Corn Starch by a Green Method and Its Application in Flame Retardance of Epoxy Resin

Abstract

Novel c-6 position oxidized corn starch (OST) with high carboxyl content (26.3–54.5%) was prepared by a green method, using hydrogen peroxide as the oxidant. The as-obtained OSTs were then used as flame-retardant carbon sources with microencapsulated ammonium polyphosphate (MFAPP) in epoxy resin (EP). Compared to EP, the obtained EP/MFAPP/OST composites exhibit significantly enhanced flame retardancy. The introduction of only 6.25 wt % OSTs and 6.25 wt % MFAPP results in remarkably increased limiting oxygen index and decreased heat release rate, and all composites can reach UL94 V-0 rating. Thermogravimetric analyses and cone calorimetry results suggest both OSTs and MFAPP have good catalytic charring effects, and the increased carboxyl content benefits the char formation of the composites. Because of the formation of compact char on the sample surface during combustion, the transfer of oxygen, heat, and flammable gas products is inhibited; the flame retardancy of EP/MFAPP/OST composites is thus remarkably enhanced.

Flame Retardant Epoxy Composites on the Road of Innovation: An Analysis with Flame Retardancy Index for Future Development

“…Hollow symbols are indicative of fiber-incorporated composites with details earlier given in the bottom of Table 1 as notes a to i . Here: DiDOPO-1.5/GN-1.5 [28], DiDOPO-10/MWCNT-0.8 [29], DiDOPO-3.5/OMMT-3.5 [30], DiDOPO-0.5/OLDH-0.5, DiDOPO-2.5/OLDH-2.5, DiDOPO-5/OLDH-5 [31], IFR-40, IFR-39/CES-1, IFR-38/CES-2, IFR-37/CES-3, IFR-35/CES-5 [208], DOPO-15/P-KC-15, DOPO-20/P-KC-10, DOPO-25/P-KC-5 [41], mAPP-5/PER-5, mAPP-5/RCC-5, mAPP-5/ORCC-5 [209], PEPA–TMA-12/MCA-6, PEPA–TMA-16/MCA-8, PEPA–TMA-20/MCA-10 [210], ZIF8-1/MgAl-LDH-1, ZIF67-1/MgAl-LDH-1 [170], TAT-18/DOPO-2, TAT-16/DOPO-4, TAT-14/DOPO-6, TAT-12/DOPO-8, TAT-18/HPCP-2, TAT-16/HPCP-4, TAT-14/HPCP-6, TAT-12/HPCP-8 [52], EDA-APP-19/Cu 2 O-2 [55], CP-6B-3/MH-0.5 [56], IFR-20, IFR-19.5/HGM-0.5, IFR-19/HGM-1, IFR-18/HGM-2, IFR-16/HGM-4 [211], APP-5/PSA-5 [58], MFAPP-6.25/PER-6.25, MFAPP-6.25/ST-6.25, MFAPP-6.25/OST-6.25 [212], EG-16/DOPO-4, EG-14/DOPO-6, EG-12/DOPO-8, EG-10/DOPO-10, EG-16/HPCP-4, EG-14/HPCP-6, EG-12/HPCP-8, EG-10/HPCP-10 [66], TMT-8.3/DOPO-2.7, TMT-8.2/DOPO-4.1, TMT-8.1/DOPO-5.6, TMT-8/DOPO-7 [67], DOPO-3/APHP-3, DOPO-4/APHP-2 [75], TAD-4/OMMT-1 [77], FR-20/APP-10, FR-15/APP-15, FR-12/APP-18, FR-10/APP-20 [213], ATCP-15/FRHA-1, ATCP-15/FRHA-3, ATCP-15/FRHA-5 [89], ATCP-15/FRHA-1, ATCP-15/FRHA-3, ATCP-15/FRHA-5 [90], APP-4/MMT-6 [93], DOPO-5/MMT-1 [94], BDP-6.7/PHP-3.3 [95], OPS-2.5/DOPO-2.5 [102], …”

The synergistic effect of cuprous oxide on an intumescent flame-retardant epoxy resin system

“…10,11 To solve these problems, an extra carbonization agent and blowing agent were used to cover the shortage of the formation amount and intumescent degree of the char. [12][13][14][15][16] Pentaerythritol (PER) and melamine (MEL) are the most commonly used sources of charring and blowing agents, respectively. Surface modication of APP is an effective method to improve its compatibility in the polymer matrix.…”

A new approach on improving the fire resistance of polyamide 11 by incorporating sulfur‐based flame retardant

“…And the residues are characterized by FTIR as shown in Figure . The typical peaks of PA 11 (2925 and 2853 cm −1 : C─H stretching vibration, 1642 cm −1 : amide I stretching vibration, 1548 cm −1 : amide II stretching vibration, and 1275 cm −1 : C─N stretching) can be detected from the spectrum at 25°C . Moreover, the peak of SA salts (SO 3 − ) can also be found at 1073 cm −1 .…”