scholarly journals Preparation and Properties of 3-Pentadecyl-phenol In-Situ Modified Foamable Phenolic Resin

Author(s):  
Tiejun Ge ◽  
Kaihong Tang ◽  
Yang Yu ◽  
Xiapeng Tan

In this present study, 3-pentadecyl-phenol was selected as a modifier to prepare a foamable phenolic resin with excellent performance, which was successfully prepared by in-situ modification. Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (1H NMR, 13C-NMR) were used to test and characterize the molecular structure of the modified resin. The results showed that 3-pentadecyl-phenol successfully modified the molecular structure of phenolic resin with a reduction in resin gel time. The effect of changing the added amount of 3-pentadecyl-phenol on the mechanical properties, microstructure and flame retardancy of the modified foam was investigated. The results showed that when the amount of added 3-pentadecyl-phenol was 15% of the total amount of phenol, this resulted in the best toughness of the modified foam, which could be increased to 300% compared to the bending deflection of the unmodified phenolic foam. The cell structure showed that the modified phenolic foam formed a more regular and dense network structure and the closed cell ratio was high. Furthermore, the compressive strength, bending strength, and limited oxygen index were improved, while the water absorption rate was lowered. However, the foam density could be kept below 40 mg/cm3, which does not affect the load.

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1124 ◽  
Author(s):  
Tiejun Ge ◽  
Kaihong Tang ◽  
Yang Yu ◽  
Xiapeng Tan

In this present study, 3-pentadecyl-phenol was selected as a modifier to prepare a foamable phenolic resin with excellent performance, which was successfully prepared by in situ modification. Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (1H NMR, 13C NMR) were used to test and characterize the molecular structure of the modified resin. The results showed that 3-pentadecyl-phenol successfully modified the molecular structure of phenolic resin with a reduction in the resin gel time. The effect of changing the added amount of 3-pentadecyl-phenol on the mechanical properties, microstructure, and flame retardancy of the modified foam was investigated. The results showed that when the amount of added 3-pentadecyl-phenol was 15% of the total amount of phenol, this resulted in the best toughness of the modified foam, which could be increased to 300% compared to the bending deflection of the unmodified phenolic foam. The cell structure showed that the modified phenolic foam formed a more regular and dense network structure and the closed cell ratio was high. Furthermore, the compressive strength, bending strength, and limited oxygen index were improved, while the water absorption rate was lowered. However, the foam density could be kept below 40 mg/cm3, which does not affect the load.


Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 334 ◽  
Author(s):  
Tiejun Ge ◽  
Kaihong Tang ◽  
Xiaojun Tang

In the present study, acetoacetic ester-terminated polyether was selected as a modifier to prepare a new type of polyether phenolic resin, which was successfully prepared by pre-synthesis modification. It is used to prepare interpenetrating cross-linked network structure modified phenolic foam with excellent mechanical properties. Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (1H NMR, 13C NMR) were used to characterize the molecular structure of the polyether phenolic resin. The results showed that the acetoacetic ester-terminated polyether successfully modified the phenolic resin and introduced a polyether skeleton into the resin structure. The effect of changing the added amount of acetoacetic ester-terminated polyether from 10% to 20% of the phenol content on the mechanical properties and microstructure of the modified phenolic foam was investigated. The results showed that when the amount of acetoacetic ester-terminated polyether was 16% the amount of phenol, this resulted in the best toughness of the modified foam, which had a bending deflection that could be increased to more than three times that of the base phenolic foam. The modified phenolic foam cell diameter was reduced by 36.3%, and the distribution was more uniform, which formed a denser network structure than that of the base phenolic foam. The bending strength was increased by 0.85 MPa, and the pulverization rate was as low as 1.3%.


Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2228 ◽  
Author(s):  
Yuxiang Yu ◽  
Yufei Wang ◽  
Pingping Xu ◽  
Jianmin Chang

Bio-oil was added as a substitute for phenol for the preparation of a foaming phenolic resin (PR), which aimed to reduce the brittleness and pulverization of phenolic foam (PF). The components of bio-oil, the chemical structure of bio-oil phenolic resin (BPR), and the mechanical performances, and the morphological and thermal properties of bio-oil phenolic foam (BPF) were investigated. The bio-oil contained a number of phenols and abundant substances with long-chain alkanes. The peaks of OH groups, CH2 groups, C=O groups, and aromatic skeletal vibration on the Fourier transform infrared (FT-IR) spectrum became wider and sharper after adding bio-oil. These suggested that the bio-oil could partially replace phenol to prepare resin and had great potential for toughening resin. When the substitute rate of bio-oil to phenol (B/P substitute rate) was between 10% and 20%, the cell sizes of BPFs were smaller and more uniform than those of PF. The compressive strength and flexural strength of BPFs with a 10–20% B/P substitute rate increased by 10.5–47.4% and 25.0–50.5% respectively, and their pulverization ratios decreased by 14.5–38.6% in comparison to PF. All BPFs maintained good flame-retardant properties, thermal stability, and thermal isolation, although the limited oxygen index (LOI) and residual masses by thermogravimetric (TG) analysis of BPFs were lower and the thermal conducticity was slightly greater than those of PF. This indicated that the bio-oil could be used as a renewable toughening agent for PF.


2020 ◽  
Vol 172 ◽  
pp. 01003 ◽  
Author(s):  
Nickolaj Feldt Jensen ◽  
Carsten Rode ◽  
Birgitte Andersen ◽  
Søren Peter Bjarløv ◽  
Eva B. Møller

The study investigated the hygrothermal performance and risk of mould growth in two thermal insulation systems for internal retrofitting purposes; a phenolic foam system with a closed cell structure, and a capillary active diffusion-open lime-cork based insulating plaster. The setup consisted of a 40-feet (12.2 m) insulated reefer container with controlled indoor climate, reconfigured with several holes (1x2 m each) containing solid masonry walls with embedded wooden elements on the interior side and different interior insulation systems, with and without exterior hydrophobisation. Focus was on the conditions in the interface between wall and insulation system, and in the embedded wooden elements. Relative humidity and temperature were measured in several locations in the test walls over two years, and the mould risk was evaluated by measurements and the VTT mould growth model. Findings for the interior phenolic foam system indicated that exposed walls experienced high relative humidity and high risk of moisture-induced problems. Exterior hydrophobisation had a positive effect on the moisture balance for the southwest oriented wall with phenolic foam. The lime-cork based insulating plaster showed high relative humidity and risk of moisture-induced problems, with and without hydrophobisation.


2011 ◽  
Vol 250-253 ◽  
pp. 523-527
Author(s):  
Wei Zhang ◽  
Yu Feng Ma ◽  
Fu Xiang Chu ◽  
Chun Peng Wang

The foamable phenolic resin was prepared by gradual copolymerization of formaldehyde, paraformaldehyde and phenol using sodium hydroxide (NaOH) as catalyst, by way of adding NaOH, paraformaldehyde in different steps. The environmental protection vesicant, foam stabilizer and mixed acid curing agent were mixed with the foamable phenolic resin to prepare flame-retardant insulation phenolic foam. The influence of the formaldehyde/phenol molar ratio on the activity, toxic residue of foamable phenolic resin was investigated. Besides, the foam cell structure, insulation and flame-retardant properties of the phenolic foam were also studied. The results showed that as the molar ratio of formaldehyde to phenol was 2.0, the free phenol content was 2.3% and hydroxymethyl content was 34.83%, the thermal conductivity was 0.046w/mk, oxygen index was 54.3% and carbon monoxide (CO) peak production was as high as 1.8584 kg/kg, which was suitable to be used as insulation and flame-retardant materials in buildings.


Author(s):  
D. Caillard ◽  
J.L. Martin

The behaviour of the dislocation substructure during the steady stage regime of creep, as well as its contribution to the creep rate, are poorly known. In particular, the stability of the subboundaries has been questioned recently, on the basis of experimental observations |1||2| and theoretical estimates |1||3|. In situ deformation experiments in the high voltage electron microscope are well adapted to the direct observation of this behaviour. We report here recent results on dislocation and subboundary properties during stationary creep of an aluminium polycristal at 200°C.During a macroscopic creep test at 200°C, a cell substructure is developed with an average cell size of a few microns. Microsamples are cut out of these specimens |4| with the same tensile axis, and then further deformed in the microscope at the same temperature and stain rate. At 1 MeV, one or a few cells can be observed in the foil thickness |5|. Low electron fluxes and an image intensifier were used to reduce radiation damage effects.


Author(s):  
Steven M. Le Vine ◽  
David L. Wetzel

In situ FT-IR microspectroscopy has allowed spatially resolved interrogation of different parts of brain tissue. In previous work the spectrrscopic features of normal barin tissue were characterized. The white matter, gray matter and basal ganglia were mapped from appropriate peak area measurements from spectra obtained in a grid pattern. Bands prevalent in white matter were mostly associated with the lipid. These included 2927 and 1469 cm-1 due to CH2 as well as carbonyl at 1740 cm-1. Also 1235 and 1085 cm-1 due to phospholipid and galactocerebroside, respectively (Figs 1and2). Localized chemical changes in the white matter as a result of white matter diseases have been studied. This involved the documentation of localized chemical evidence of demyelination in shiverer mice in which the spectra of white matter lacked the marked contrast between it and gray matter exhibited in the white matter of normal mice (Fig. 3).The twitcher mouse, a model of Krabbe’s desease, was also studied. The purpose in this case was to look for a localized build-up of psychosine in the white matter caused by deficiencies in the enzyme responsible for its breakdown under normal conditions.


2020 ◽  
Vol 35 (2) ◽  
pp. 221-228
Author(s):  
S.-B. Chen ◽  
T.-X. Li ◽  
S.-H. Wan ◽  
X. Huang ◽  
S.-W. Cai ◽  
...  

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