Investigating the nanomechanical behavior of thermosetting polymers using high-temperature nanoindentation. (September 2015)

• Record Type: Journal Article
• Authors: Wang, Xinzhou; Li, Yanjun; Wang, Siqun; Deng, Yuhe; Xing, Dong; He, Shuangshuang
• Is Part Of: European polymer journal. Volume 70(2015)
• Page Start: 360
• Page End: 370
• Publication Date: 2015-09
• Subjects: Thermosetting polymers -- Curing behavior -- Nanomechanical properties -- Temperature effects -- Nanoindentation -- Morphology; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; Polymerization; Polymers; Periodicals; Electronic journals; 547.705
• DOI: 10.1016/j.eurpolymj.2015.07.037
• Languages: English
• ISSNs: 0014-3057

Abstract

Graphical abstract: Highlights: Obtaining nanomechanics of cured thermosetting polymers during heating. Temperature exerted a positive effect on the mechanics of UF, PF, and pMDI. The curing behavior of polymers is prone to be affected by wood material. Different cure states resulted in a different indentation response of polymers. Abstract: High-temperature nanoindentation to investigate the temperature-dependent mechanical behavior of thermosetting polymers is introduced. Both the elastic modulus and hardness of three widely used adhesive polymers (phenol formaldehyde, urea formaldehyde, and polymeric isocyanate) in the pure phase and in the individual phase in wood-based composites were determined within a certain temperature range (from room temperature to 160 °C). The results indicated that Loblolly pine accelerated the curing of urea formaldehyde, whereas negatively affected the curing of phenol formaldehyde. The different cure states resulted in significantly different indentation responses between the pure polymer and the polymer within composite. Temperature exerted a positive effect on the mechanical properties of adhesive polymers. The adhesive polymers showed higher reduced elastic modulus ( Er ) and hardness ( H ) at elevated temperatures as compared to room temperature, possibly due to the positive contributions of the removal of moisture and post-polymerization. Irregular particles and micropores observed on the surface of polymer within wood-adhesive composite seem to provide evidence for the post-polymerization of the adhesive during the heating test.