Physicomechanical and thermal properties of moldings made from liquefied wood‐based novolak PF resins under various hot‐pressing conditions

Lee, Wen‐Jau; Chen, Yi-Chun; Wu, Chiou-Chang; Juan, Yu-Mei

doi:10.1002/app.30066

Cited by 12 publications

(10 citation statements)

References 27 publications

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“…During the period of liquefaction with phenol as a solvent, the chemical components of biomass will be degraded and decomposed to various oligomers and monomers and will react with phenol to form hydroxyl benzyl derivatives containing the phenolic functional groups, which can react with formaldehyde, just like phenol (Lin et al 2001;Zhang et al 2006). The phenolliquefied biomass is suitable as raw material to prepare novolak-type PF resins (Lin et al 1995;Alma et al 1996;Lee et al 2002a;Lee and Chen 2008;Lee et al 2009) and resoltype PF resins (Lee et al 2002b;Hassan et al 2009), which can be utilized for moldings or adhesives. However, their applicability as raw materials to prepare spherical PF beads is not known.…”

Section: Introductionmentioning

confidence: 98%

Spherical PF resin beads prepared from phenol-liquefied Bambusa dolichoclada with suspension polymerization

Lee

Chang

et al. 2011

Holzforschung

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Bambusa dolichoclada Hayata (long-shoot bamboo) was liquefied in phenol with H 2 SO 4 as a catalyst. The phenol-liquefied bamboo was then used as a raw material to prepare spherical phenol-formaldehyde (PF) resin beads by a suspension polymerization in a two-step process. The influence of the stirring speed (300, 350 and 400 rpm), the stabilizer dosage (3%, 4% and 5%) and the total molar ratio of formaldehyde to free phenol (F/P) (3.0/1, 3.5/1 and 4.0/1) on the properties of spherical PF beads was investigated. The results show that the yield, diameter and dimensional distribution of prepared PF beads were influenced by reaction conditions. The diameter of beads decreased as the stabilizer dosage increased. It had a more uniform dimensional distribution when stirred with a speed of 400 rpm. Differential scanning calorimetry analysis shows that PF beads obtained were not completely cured and the post-curing reaction took place at temperatures exceeded 1508C. As revealed by thermal gravimetric analysis, the char yield was over 60% after heating to 8008C.

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Section: Introductionmentioning

confidence: 98%

Spherical PF resin beads prepared from phenol-liquefied Bambusa dolichoclada with suspension polymerization

Lee

Chang

et al. 2011

Holzforschung

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“…Phenolic resins are preferred for aircraft interiors due to the extraordinary fire, smoke, and toxicity characteristics. Due to their excellent ablative properties, they are also used to manufacture carbon–carbon composites, rocket nozzles and heat shields . However, the major shortcoming is the evolution of volatiles during high temperature curing, which necessitates application of expensive processing equipment like autoclave, hydroclave, or hot press .…”

Section: Introductionmentioning

confidence: 99%

Properties and curing behavior of reactive blended allyl novolak with bismaleimide using dicumyl peroxide as a novel curing agent

Jiang

Wang

Farhan

et al. 2014

J of Applied Polymer Sci

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For reducing the cure temperature and improving the thermal stability and mechanical properties, a thermosetting resin system composed of novolak and bismaleimide (BMI) was developed by reactive blending and using dicumyl peroxide (DCP) as a novel curing agent. Novolak was allylated and reacted with BMI to produce bismaleimide allylated novolak (BAN), and the effect of DCP on flexural, impact and heat distortion temperature of cured resin were investigated. On the basis of improved mechanical and thermal properties at 0.5% DCP contents, the curing behavior of DCP/BAN resin system was evaluated by DSC analysis. Ene, Diels-Alder, homo-polymerization and alternating copolymerization which occurred in DCP/BAN resin system were further verified using FTIR at sequential cure conditions from 140 to 200 C. Kissinger and Ozawa-Flynn-wall methods were used to optimize the process and curing reactions of DCP/BAN resin system. The results showed that the addition of 0.5% DCP in BAN reduced the curing temperature and time of the modified resin. For evaluating process ability of the modified system, composite samples using polyvinyl acetyl fiber were molded and tested for flexural properties. The resulting samples showed better flexural properties when compared with the composite made with neat BAN. The modified 0.5% DCP/BAN resin system with good mechanical properties and manufacturability can be used for making bulk molding compounds and fiber reinforced composites required in various commercial and aerospace applications.

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“…Additionally, if the LW is prereacted with formalin, the thermal fluidity can be improved and the physical, mechanical, and thermal stability of MPs improve too (Lin et al 1995;Alma and Kelley 2000;Lee et al 2002). Novolaks with favorable thermomelting characteristics can be prepared by mixing LW with formalin without extra heating (Lee and Chen 2008) and resin powders made of it are suited for preparation of MPs (Lee et al 2009). …”

Section: Introductionmentioning

confidence: 97%

Properties of molding plates made with various matrices impregnated with PF and liquefied wood-based PF resins

Lee¹,

Lee²,

Hsu³

et al. 2013

Holzforschung

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Phenol (P) and phenol-liquefied wood (LW; Cryptomeria japonica, Japanese cedar) have been reacted with formalin and ammonium hydroxide as a catalyst to prepare alcohol-soluble phenol-formaldehyde (PF) resins named PF and LWPF, respectively. The resins prepared were dehydrated, diluted with ethanol, and impregnated into wood powders, filter papers, and cloths. The PF resinimpregnated matrix materials were then hot-pressed to form molding plates (MP) and their properties were tested. Differential scanning calorimetric (DSC) analysis shows that both PF and LWPF behave as hot-melting resins and are able to further condensation reactions to form a set resin. However, the maximal temperatures of LWPF are shifted to a higher temperature range compared with PF. MPs made with LWPF-impregnated materials have poorer performance than that of PF. However, the bending strength of MP with filter paper is 96.8 MPa, which fits the request of CNS 10559. The MPs made of filter papers have the best mechanical properties followed by MPs with wood powders and cloths.

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Physicomechanical and thermal properties of moldings made from liquefied wood‐based novolak PF resins under various hot‐pressing conditions

Cited by 12 publications

References 27 publications

Spherical PF resin beads prepared from phenol-liquefied Bambusa dolichoclada with suspension polymerization

Spherical PF resin beads prepared from phenol-liquefied Bambusa dolichoclada with suspension polymerization

Properties and curing behavior of reactive blended allyl novolak with bismaleimide using dicumyl peroxide as a novel curing agent

Properties of molding plates made with various matrices impregnated with PF and liquefied wood-based PF resins

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