The novel application of chitosan: Effects of cross-linked chitosan on the fire performance of thermoplastic polyurethane

A novel inorganic and organic composite flame retardant (9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide [DOPO]–layered double hydroxide [LDH]) was synthesized via grafting DOPO with organic‐modified Mg/Al‐LDH, which was introduced into poly (methyl methacrylate) (PMMA) resin to prepare the flame‐retardant PMMA composites. Thermogravimetric analyzer (TGA) showed that the T‐50% of DOPO‐LDH/PMMA composites enhanced by about 20°C, and with the 20% flame retardant, the residual char content can be increased by 39.8% in the air atmosphere compared with LDH/PMMA composites. In the UL‐94 and the limiting oxygen index (LOI) tests, it can be found that compared with LDH/PMMA composites, the LOI value of DOPO‐LDH/PMMA composites were raised evidently with the increased flame retardants, and the droplet combustion was greatly improved. These results could be ascribed to the action of DOPO free‐radical, catalytic charring of polymer and the effect of LDH physical barrier. Moreover, the novel DOPO‐LDH not only given PMMA a good flame‐retardant property and thermal stability, but also have higher visible light transmittance, ultraviolet‐shielding effect, and low loss of mechanical properties, which could further facilitate the wide application of inorganic environment‐friendly flame retardants in general resins and engineering resins and broaden the application of polymers.

Section: Resultsmentioning

confidence: 98%

Section: Ftir Analysismentioning

confidence: 98%

A flame‐retardant DOPO‐MgAl‐LDH was prepared and applied in poly (methyl methacrylate) resin

Meng

Leng

et al. 2019

“…The CS derivative associated with APP has a good flame retardant effect on TPU. And it has been reported that the fire risk of TPU could be reduced by the mixture of cross‐linked CS and APP . The above results show that CS is a good carbon source, which can be combined with APP to reduce the fire risk of the polymer.…”

Section: Introductionmentioning

confidence: 78%

Flame retardancy and thermal decomposition behavior of TPU/chitosan composites

Jiao

Chen

et al. 2019

The application of chitosan (CS) in new materials is a hot research topic. In this paper, CS was used alone as flame retardant to prepare thermoplastic polyurethane elastomer (TPU) composites. Then, the flame retardancy and thermal decomposition behavior of TPU/CS composites were intensively investigated using cone calorimeter test (CCT), scanning electron microscope (SEM), microscale combustion colorimeter (MCC) test, thermogravimetric analysis/infrared spectrometry (TG‐IR), and gas chromatography‐mass spectrometry (GC‐MS). The results showed that CS can reduce the fire risk of TPU; 2.0‐wt% CS could make the peak value of heat release rate (pHRR) decreased to 457.2 kW/m2, reduced by 65.9% compared with TPU. And the peak value of smoke production rate (pSPR) and total smoke release (TSR) of the same sample was decreased by 79.4% and 54.2%, respectively. The TG‐IR and GC‐MS results confirmed that CS could promote TPU decomposition in advance, reacting with the decomposition products of TPU. Therefore, the production of combustible gas was reduced. The GC‐MS results showed that the production of isocyanates and ethers was reduced with the addition of CS. The digital photographs of SEM for the samples after CCT were shown that the char residue layer of the sample containing 2.0‐wt% CS was fibrous in shape. It could be speculated that the thermal decomposition products from TPU could react with CS at low temperature, which reduced the production of flammable gases. So CS had a good prospect in reducing the fire hazard for TPU.

“…It is apparently the thermal degradation of pure TPU contains two stages: the first stage around 300°C to 380°C is due to the fracture of TPU chains, and the second stage around 380°C to 500°C corresponded to the further destruction of C―C and C―O bonds on the main chain . But for TPU composites, the thermal degradation process goes through three stages, which mainly consist of the degradation of IFR, catalysis of the charring process, and decomposition of the main chain of TPU . The temperature at 5% and 10% mass loss (T 5% , T 10% ) of all TPU samples are defined as the onset temperature of the decomposition.…”

Section: Resultsmentioning

confidence: 99%

“…23 But for TPU composites, the thermal degradation process goes through three stages, which mainly consist of the degradation of IFR, catalysis of the charring process, and decomposition of the main chain of TPU. 38 The temperature at 5% and 10% mass loss…”

Section: Thermal Degradation Behaviormentioning

confidence: 99%

Synergistic effect between solid wastes and intumescent flame retardant on flammability and smoke suppression of thermoplastic polyurethane composites

Zhou

Liu

Zhou

et al. 2019

Phosphorus tailings and fly ash both are solid wastes and do harm to the environment. Here, they were added into thermoplastic polyurethane (TPU) matrices together with intumescent flame retardants (IFR), and the synergistic effects between IFR and phosphorus tailings or fly ash for improving the flame retardancy of TPU were investigated. The cone calorimeter test (CCT) results indicated that adding phosphorus tailings or fly ash substitute for part of IFR could obtain a better flame retardant effect. The peak heart release rate (PHRR) of TPU/25 wt% IFR composites exhibited a reduction of 77% than that of neat TPU, and the total smoke production presented a reduction of 16%. However, the PHRR value and total smoke production of the sample TPU/20 wt% IFR/5 wt% phosphorus tailings were reduced by 91% and 57%, respectively, compared to that of neat TPU. The dense char promoted by the presence of IFR and phosphorus tailings or fly ash delayed the diffusion of volatile pyrolysis products and transmission of heat and oxygen to the underlying material. Therefore, a certain amount of phosphorus tailings or fly ash can be used as synergistic agents with IFR to enhance the fire safety of TPU materials. From another aspect, it also provides a promising way for recycling use of phosphorus tailings and fly ash.