Effects of ammonium polyphosphate microencapsulated on flame retardant and mechanical properties of the rigid polyurethane foam

Abstract

In this article, a flame retardant microcapsule ammonium polyphosphate microencapsulated by polyurea (POAPP) was successfully synthesized by interfacial polymerization method using ammonium polyphosphate (APP) as core and polyurea as shell. The microencapsulation is observed by scanning electron microscopy and characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis and hydroscopicity test, which prove the success in synthesizing microencapsulation. When the POAPP is added into rigid polyurethane foam (RPUF), the flame retardant and mechanical properties are investigated using cone calorimeter, limited oxygen index test, and compressive strength test. The PHRR of RPUF‐POAPP20 decreased from 336.52 kW/m2 (Ref. RPUF) to 203.84 kW/m2 and the THR of RPUF‐POAPP20 was only 7.6 MJ/m2, which is 33.9% lower than that of Ref. RPUF. Furthermore, the limiting oxygen index of RPUF‐POAPP20 reaches 24.8%, which increased by 36.3% compared to Ref. RPUF. Whereas the maximum compressive strength of RPUF‐POAPP5 was 7.46 MPa, which is higher than that of RPUF‐APP5.

Impacts of cellulose nanofibers on the morphological behavior and dynamic mechanical thermal properties of extruded polylactic acid/cellulose nanofibril nanocomposite foam

“…16,17 Elements for the mercantile growth of foams contain lightness, inexpensiveness, lower thermal conductivity, a broad domain of formulations from hard foam to elastic foam, a number of different processes, simple production of various parts, absence of pressure in several production methods, the higher strength-to-mass ratio in analogy to another polymer families and great impact. [18][19][20][21] In extrusion foaming processes, due to the high pressure, the gas injected into the polymer melt dissolves. The dissolution of the gas causes the polymer melt to plasticize, resulting in a uniform polymer-gas mixture flowing along the extruder.…”

“…Polymer with bubbles of gas makes polymer foams which are caused by the blowing agent and classified into three categories as regular, microcellular (cell size: <10 μm and cell density: 10 9 –10 12 cells/cm 3 ), and nanocellular (cell size: <1 μm and cell density: >10 15 cells/cm 3 ) 16,17 . Elements for the mercantile growth of foams contain lightness, inexpensiveness, lower thermal conductivity, a broad domain of formulations from hard foam to elastic foam, a number of different processes, simple production of various parts, absence of pressure in several production methods, the higher strength‐to‐mass ratio in analogy to another polymer families and great impact 18–21 …”

Fire performance of piperazine phytate modified rigid polyurethane foam composites

“…Compared with RPUF, the PHRR of RPUF/PA‐Pi10 was decreased to 217.9 kW/m 2 . It was also found that RPUF/PA‐Pi20 and RPUF/PA‐Pi30 presented increased PHRR values which can be ascribed that PA‐Pi reduced the thermal stability of polyurethane molecular chain 6 . As shown in Figure 7(B), the THR of RPUF/PA‐Pi composites showed an obvious downward trend.…”

“…At the same time, due to its porous structure and organic skeleton, RPUF exhibited rapidly fire spread speed with the release of smoke and toxic gases, causing serious casualties and property losses 5 . Therefore, how to effectively enhance fire performance of RPUF composites is an urgent problem to be solved in the industry 6 …”

Flame Retarded Rigid Polyurethane Foams Composites Modified by Aluminum Diethylphosphinate and Expanded Graphite

“…Cheng et al prepare polyurea microencapsulated ammonium polyphosphate (POAPP), which is further applied into RPUF/POAPP composites. It is observed that RPUF/ POAPP20 with 20 wt% POAPP loading possessed LOI of 24.8 vol% with 33.9% decrease of PHRR value compared with virgin RPUF (Cheng et al, 2020). Tang et al combine melamine polyphosphate with steel slag; 2.5 wt% of steel slag and 7.5 wt% of MPP made RPUF composites reach LOI of 24.0 vol% .…”