scholarly journals Lignin-Based Phenolic Foam Reinforced by Poplar Fiber and Isocyanate-Terminated Polyurethane Prepolymer

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1068
Author(s):  
Guoliang Chen ◽  
Jian Liu ◽  
Wei Zhang ◽  
Yanming Han ◽  
Derong Zhang ◽  
...  

Phenolic foams (PFs) are lightweight (<200 kg/m3), high-quality, and inexpensive thermal insulation materials whose heat and fire resistance are much better than those of foam plastics such as polyurethane and polystyrene. They are especially suitable for use as insulation in chemical, petroleum, construction, and other fields that are prone to fires. However, PFs have poor mechanical properties, poor abrasion resistance, and easy pulverization. In this paper, a polyurethane prepolymer was treated with an isocyanate, and then the isocyanate-terminated polyurethane prepolymer and poplar powder were used to prepare modified lignin-based phenolic foams (PUPFs), which improved the abrasion resistance and decreased the pulverization of the foam. The foam composites were comprehensively evaluated by characterizing their chemical structures, surface morphologies, mechanical properties, thermal conductivities, and flame-retardant properties. The pulverization ratio was reduced by 43.5%, and the thermal insulation performance and flame-retardancy (LOI) were improved. Compared with other methods to obtain lignin-based phenolic foam composites with anti-pulverization and flame-retardant properties, the hybrid reinforcement of foam composites with an isocyanate-terminated polyurethane prepolymer and poplar powder offers a novel strategy for an environmentally friendly alternative to the use of woody fibers.

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 148 ◽  
Author(s):  
Jian Liu ◽  
Liuliu Wang ◽  
Wei Zhang ◽  
Yanming Han

Phenolic foam composites (PFs) are of substantial interest due to their uniform closed-cell structure, low thermal conductivity, and good thermal insulation performance. However, their disadvantages of a high pulverization rate and poor mechanical properties restrict their application in building exterior insulation. Therefore, the toughening of these composites is necessary. In this paper, poplar fiber was treated with an acetylation reagent, and the acetylated fiber was used to prepare modified phenolic foams (FTPFs); this successfully solved the phenomenon of the destruction of the foam structure due to the agglomeration of poplar fiber in the resin substrate. The foam composites were comprehensively evaluated via the characterization of their chemical structures, surface morphologies, mechanical properties, thermal conductivities, and flame retardant properties. It was found that the compressive strength and compressive modulus of FTPF-5% respectively increased by 28.5% and 37.9% as compared with those of PF. The pulverization ratio was reduced by 32.3%, and the thermal insulation performance and flame retardant performance (LOI) were improved. Compared with other toughening methods for phenolic foam composites, the phenolic foam composites modified with surface-compatibilized poplar fiber offer a novel strategy for the value-added utilization of woody fiber, and improve the toughness and industrial viability of phenolic foam.


2013 ◽  
Vol 709 ◽  
pp. 242-245
Author(s):  
Zheng Qin Liu ◽  
Wei Guo Liu ◽  
Xiu Li Qiu ◽  
Yu Qing Zhang ◽  
Fan Dong Kong

Phenolic fiber is a new fiber and has excellent flame retardant properties. In order to investigate the textile possibility of phenolic fiber and to develop protective clothing and decorative fabrics containing phenolic fiber, the mechanical properties of phenolic fiber were studied firstly, then the polyester fiber was chosen to blend with different portion of phenolic fiber to enhance the strength of the blended yarn and finally the fabrics were knitted with different blended yarns. The strength and wear resistance of different blending ratio of phenolic/polyester blended yarn, and the bursting strength, abrasion resistance and flame retardant properties of the blended fabrics were analyzed and compared. The experimental results shows that the breaking tenacity and elongation at break are low, only 1.3 cN/dtex and 9.4%, respectively, which is not suitable for 100% phenolic fiber to be processed in yarn. The strength and wear resistance of the phenolic/polyester blend yarns and their knitted fabrics increase while the contents of polyester are increased. The flame retardant of phenolic/polyester blend fabrics is improved greatly due to phenolic fiber. Therefore, it is necessary for phenolic fiber to modify its strength and extension in order to be able to get the 100% phenolic yarn and products and in order to give full play to the excellent characteristics of the phenolic fiber.


2011 ◽  
Vol 393-395 ◽  
pp. 1012-1017 ◽  
Author(s):  
Yu Feng Ma ◽  
Wei Zhang ◽  
Ling Li ◽  
Ming Ming Zhang ◽  
Zeng Hui Cheng ◽  
...  

New composite foams were prepared by co-foaming of Melamine-Urea-Formaldehyde (MUF) resin and wood fiber in the closed mould at 70°C. The effects of amount of wood fiber on mechanical properties, brittleness, flame-retardant, insulation and microscopic structures of wood fiber-MUF foam were investigated. Results indicated that the flame-retardant properties increased, and the brittleness and mechanical properties decreased with the increase of the amount of wood fiber in composite foams. The addition of wood fiber resulted in more uniform cell size distribution and irregular cell shape, but had little effect on insulation properties.


2015 ◽  
Vol 30 (6) ◽  
pp. 816-826 ◽  
Author(s):  
Yiren Huang ◽  
Jianwei Yang ◽  
Zhengzhou Wang

Flame-retardant properties of ammonium polyphosphate (APP) and its two microcapsules, APP with a shell of melamine–formaldehyde (MF) resin (MFAPP) and APP with a shell of epoxy resin (EPAPP), were studied in styrene–butadiene–styrene (SBS). The results indicate that APP after the microencapsulation leads to an increase in limiting oxygen index in SBS compared with APP. When dipentaerythritol is incorporated into the SBS composites containing the APP microcapsules, a further improvement in flame retardancy of the composites is observed. The microencapsulation does not result in much improvement of mechanical properties. Moreover, the effect of a compatibilizer (SBS grafted with maleic anhydride) on flame-retardant and mechanical properties of SBS/APP composites was investigated.


2019 ◽  
Vol 2019 ◽  
pp. 1-25 ◽  
Author(s):  
Shaolin Lu ◽  
Wei Hong ◽  
Xudong Chen

Polymer materials are ubiquitous in daily life. While polymers are often convenient and helpful, their properties often obscure the fire hazards they may pose. Therefore, it is of great significance in terms of safety to study the flame retardant properties of polymers while still maintaining their optimal performance. Current literature shows that although traditional flame retardants can satisfy the requirements of polymer flame retardancy, due to increases in product requirements in industry, including requirements for durability, mechanical properties, and environmental friendliness, it is imperative to develop a new generation of flame retardants. In recent years, the preparation of modified two-dimensional nanomaterials as flame retardants has attracted wide attention in the field. Due to their unique layered structures, two-dimensional nanomaterials can generally improve the mechanical properties of polymers via uniform dispersion, and they can form effective physical barriers in a matrix to improve the thermal stability of polymers. For polymer applications in specialized fields, different two-dimensional nanomaterials have potential conductivity, high thermal conductivity, catalytic activity, and antiultraviolet abilities, which can meet the flame retardant requirements of polymers and allow their use in specific applications. In this review, the current research status of two-dimensional nanomaterials as flame retardants is discussed, as well as a mechanism of how they can be applied for reducing the flammability of polymers.


2015 ◽  
Vol 1120-1121 ◽  
pp. 519-522
Author(s):  
Xiao Wen Ren ◽  
Ya Ping Zhu ◽  
Fan Wang ◽  
Hui Min Qi

Phenolic resin modified with methylvinylcyclosilazanes (MVSZ) were prepared and their flame-retardant properties were investigated, and results exhibited that the Limited Oxygen Index (LOI) values increased with the content increasing of MVSZ, and the LOI reach to 40.8, when the content of MVSZ was 26.0%. The flame-retardant and mechanical properties of polyester fabrics reinforced phenolic resin modified with silazanes (PFMS) composites were measured, the results indicated that the LOI and flexural strength were enhanced compared with those of phenolic resins composites.


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