Preparation and Properties of Polyimide/Mesoporous SiO2 Composite Films with Low Dielectric Constant
Zi-xiang Wang,
Rong-rong Zheng,
Lei Han,
Shu-wu Chen,
Hong-tao Wu,
Jing-ying Wang,
Xing-wei Li,
Hongjing Liu,
Liyan Wang
Issue:
Volume 8, Issue 2, June 2022
Pages:
21-27
Received:
11 April 2022
Accepted:
4 May 2022
Published:
24 May 2022
DOI:
10.11648/j.ajpst.20220802.11
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Abstract: In this paper, mesoporous silica (NH2-SiO2) containing amino groups was firstly prepared using amino-ended hyperbranched polyamides as template agent and KH550 as surface treatment agent, and then polyimide/mesoporous NH2-SiO2 composites with low dielectric constant were successfully prepared by in situ polymerization method. The composite materiasl not only have excellent thermal properties but also have a very low dielectric constant compared to pure polyimides. The SEM results show that the surface of mesoporous NH2-SiO2 has an increased amount of wrinkles after surface treatment, and a uniform film is formed due to the excellent compatibility of mesoporous NH2-SiO2 containing amino groups with polyimides. The excellent heat resistance themselves can improve the thermal performance of the composite films. In addition, their mesoporous property increase the proportion of air (the minimum dielectric constant is 1.00056) in the composite films and reduce their dielectric performance. When the addition amount is 5 wt%, the dielectric constant of the composites at 10 MHz is 2.39, the dielectric loss is 0.02, and the glass transition temperature is 222.92°C. Therefore, the present work provides a promising solution for the preparation of PIs for the microelectronics industry with low dielectric constant and excellent thermal properties.
Abstract: In this paper, mesoporous silica (NH2-SiO2) containing amino groups was firstly prepared using amino-ended hyperbranched polyamides as template agent and KH550 as surface treatment agent, and then polyimide/mesoporous NH2-SiO2 composites with low dielectric constant were successfully prepared by in situ polymerization method. The composite materias...
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Valorization of the Pn-Pozzolana to the Synthesis of Fe-pn-Pozzolana Study - Application to the Synthesis of the Fe-Pn-SiO2
Andry Tahina Rabeharitsara,
Ando Princia Randriamalala,
Nambinina Richard Randriana,
Baholy Robijaona,
Marie Hanitriniaina Ratsimba
Issue:
Volume 8, Issue 2, June 2022
Pages:
28-37
Received:
12 July 2022
Accepted:
27 July 2022
Published:
5 August 2022
DOI:
10.11648/j.ajpst.20220802.12
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Abstract: The valorization of pozzolana into pn-pozzolana used as water softening was studied. This article treated particularly the valorization of the pn-pozzolana and pn-SiO2 by adding iron-Fe atoms to give the Fe-pn-pozzolana and Fe-pn-SiO2. Two synthesis procedures were used with the ironIIethoxide Fe(OEt)2 as precursor material of the iron-Fe atoms deposits on the pn-pozzolana: first there was the solid-solid synthesis where the pn-pozzolana and the Fe(OEt)2 are both in solid phase; then there was the solid-liquid synthesis where the Fe(OEt)2 was a liquid phase solution and pn-pozzolana still in solid phase. It was found that the conversion of the Fe(OEt)2 deposited on the pn-pozzolana depended very significantly on its amount in relation to the pn of the pn-pozzolana. Thus, as the amount of the Fe(OEt)2 increased, so its conversion and thus the deposit of the iron-Fe atoms on the pn-pozzolana was better. The ratio noted: “7×n”; where n was the moles numbers of the Fe(OEt)2 on each monomer unit composing the pn; allowed to parameterize each tests. Thus, seeing that one mole of pn contains 7 moles of pn, hence the total number of the Fe(OEt)2 deposited in an n-pn trial was "7×n". Consequently, it was shown that the radical mechanism of the iron-Fe atoms depositions on the pn-pozzolana or the pn-SiO2 by the intermediate of the Fe(OEt)2 passed initially by the formation of an intermediate by dismutation of the neighboring molecules of the Fe(OEt)2 with iron-Fe atoms depositions followed by the formation of a by-product “diethyl-peroxide” with other iron-Fe atoms depositions by which the reactions progress had been followed. This mechanism allowed to understand and explain the excellence of the iron-Fe atoms depositions on pn-pozzolana or pn-SiO2. Thus, a kinetic study of this Fe(OEt)2 on the pn-pozzolana followed by the iron-Fe atoms depositions had been carried out at 55°C with the optimum ratio "7×4" and allowed to evaluate and calculate the value of its rate constant of the order of 0.6841 [mol×l-1×s-1] with 2nd partial order in relation to the Fe(OEt)2. Finally, some Fe-pn-pozzolana and Fe-pn-SiO2 materials were synthesized followed by their characterizations in particular by xrf-spectrophotometer which made it possible to confirm the pn's role of the pn-pozzolana as support promoting the excellent iron-Fe atoms depositions on the pn-pozzolana or the pn-SiO2 by the intermediate of the ironIIethoxide Fe(OEt)2 with weight dispersion and alkene rate in the order respectively of 5.11% à 23.02% and 5.59E-4 [mol×g-1] to 8.91E-4 [mol×g-1].
Abstract: The valorization of pozzolana into pn-pozzolana used as water softening was studied. This article treated particularly the valorization of the pn-pozzolana and pn-SiO2 by adding iron-Fe atoms to give the Fe-pn-pozzolana and Fe-pn-SiO2. Two synthesis procedures were used with the ironIIethoxide Fe(OEt)2 as precursor material of the iron-Fe atoms dep...
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