A high performance polymer with both low water uptake and high thermostability derived from a biorenewable plant oil (anethole) is reported here. By using the plant oil as the feedstock, a new monomer containing benzocyclobutene and vinyl units was successfully synthesized. The monomer was then converted to a polymer via radical polymerization, and the polymer was further postpolymerized to form an insoluble and infusible cross-linked network at high temperature (>200 °C). The cross-linked network exhibited water uptake of below 0.40% (kept at boiling water for 4 days) and dielectric constant of less than 2.9 at a range of frequencies varying from 1.0 to at 30.0 MHz at room temperature. TGA and TMA data showed that the cross-linked network had 5 wt % loss temperature of 432 °C (in N2) and a Tg of 369 °C, respectively. The cross-linked network also showed low thermal expansion coefficient of 41.24 ppm/°C at the range of temperatures varying from 50 to 300 °C. Nanoindentation tests indicated that the cross-linked film had an average hardness of 0.87 GPa and a Young’s modulus of 11.40 GPa. These data suggest that the new polymer derived from anethole possess excellent thermal and mechanical properties, and it has potential application in the microelectronic industry.Keywords: Anethole; Biomass; High performance polymer; Plant oil; Thermosetting polymer;

The conversion of a biorenewable plant oil (anethole) to a new fluoropolymer with both low dielectric constant and low water uptake is reported here. First, cationic polymerization of plant oil by using CF3SO3H as an initiator gave a polymer, which was then functionalized by introducing the thermocrosslinkable -OCF═CF2 groups via a three-step procedure. The obtained fluoropolymer can be easily thermally converted to an infusible and insoluble cross-linked network exhibiting low water uptake (<0.24%, in water of 96 °C for 4 days) and low dielectric constant (<2.64 at a range of frequencies varying from 1.0 to at 30 MHz at room temperature). TGA and DMA data showed that the cross-linked network had 5 wt % loss temperature of 400 °C (in N2) and a Tg of 160 °C, respectively. Nanoindentation tests indicated that the cross-linked film had an average hardness of 0.239 GPa and a Young’s modulus of 6.11 GPa. These results mean that the new polymer derived from biorenewable anethole is comparable to the petroleum-based materials, implying that the low k polymers widely utilized in microelectronic industry will have a new sustainable feedstock supply.Keywords: Anethole; Biomass; Dielectric constant; Fluoropolymer; Plant oil

An intrinsically microporous fluoropolymer has been successfully synthesized through thermo-cross-linking of a functional monomer having a quaternary carbon center and thermopolymerizable trifluorovinyl ether groups as the side chains. Because the monomer has a tetrahedral configuration, the thermo-cross-linking produces spontaneously formed micropores with an average size of 8 Å in the polymer. Because of the existence of the micropores, the fluoropolymer exhibits excellent dielectric properties with dielectric constant (Dk) of 2.36 and dissipation factor (Df) of 1.29 × 10–3 at a frequency of 5 GHz. Moreover, the polymer shows very low water uptake (<0.08% in water of 99 °C for 72 h) and high transparency (transmittance of 93% varying from 400 to 1100 nm). TGA and DMA data show that the polymer has 5 wt % loss temperature of 492 °C (in N2) and Young’s modulus of 4.95 GPa, respectively. These results suggest that the polymer is very suitable as the matrix resin for the production of the composites utilized in high-frequency printed circuit boards (HF-PCBs). In particular, this work is the first example for the production of a low Dk and Df polymer using a strategy of spontaneously forming pores. Because HF-PCBs have a broad range of applications, this contribution is of considerable industrial importance.

Three s-triazine-based functional monomers with thermo-polymerizable propargyl-ether units were synthesized by a facile procedure. These monomers can be thermally cured to form the crosslinked networks, which showed 5-wt% loss temperature of up to 400 °C and the char yields of more than 50% at 1000 °C. Moreover, the crosslinked networks exhibited the coefficients of thermal expansion (CTE) of below 43 ppm °C−1 varying from 30 to 300 °C and glass transition temperatures (Tg) of up to 290 °C, respectively. These monomers were also used to improve the thermostability of a commercial bismaleimide (4,4′-bismaleimidodiphenylmethane). The results indicated that blending the bismaleimide and the triazine monomers gave the new resins, which showed higher Tg and lower CTE than the bismaleimide, suggesting the triazine monomers can be considered as the modifiers for enhancement of the thermostability of the commercial bismaleimides.s-Triazine-based functional monomers with thermo-polymerizable propargyl-ether units are reported here. Thermopolymerization of the monomers gave the crosslinked networks, showing high low coefficients of thermal expansion (CTE) high glass transition temperatures (Tg). These monomers were also used to improve the properties of a commercial bismaleimide, producing the copolymers with the better thermostability than that the neat bismaleimide.

A propargyl ether-functionalized poly(m-phenylene) (PE-PMP) is reported here. This polymer exhibits good solubility and film-forming ability. After postpolymerization at high temperature, the polymer transforms to a cross-linked network, which shows high thermostability with a 5% weight loss temperature at 471 °C and a char yield of 67% at 1000 °C under N2. Thermo-mechanical analysis (TMA) reveals that the cured polymer shows an average linear coefficient of thermal expansion (CTE) of 30.6 ppm °C−1 ranging from 30 to 300 °C and a glass transition temperature (Tg) near 330 °C. Moreover, even at temperatures up to 300 °C, the cured polymer possesses a storage modulus exceeding 4.0 GPa. These data are superior to those of the commercial epoxy and novolac resins and polyimides. Furthermore, the cured polymer film has good mechanical properties with hardness, Young's modulus and a bonding strength to a silicon wafer of 1.22, 9.44 and 0.78 GPa, respectively. The cured polymer film also shows good dielectric properties with an average dielectric constant of 2.93 in a range of frequencies from 2 MHz to 30 MHz. Such results suggest that the polymer is a useful precursor for preparation of insulating materials with high modulus and Tg in the microelectronics industry.

A novel benzocyclobutene-functionalized poly(m-phenylene) was synthesized. This polymer showed good solubility and film-forming ability. When being heated at high temperature, the polymer film converted to an insoluble cross-linked network structure and did not show any cracks. Thermogravimetric analysis of the polymer film exhibited a weight loss of 5% at 547 °C and a char yield of 71% at 1000 °C in nitrogen. Moreover, the cured film had good dielectric and mechanical properties. In a range of frequencies from 0.10 MHz to 30 MHz, the cured film showed dielectric constant of less than 2.7, which was comparable with these of polyimides, polycyanates and the SILK resins. On a nano indenter system, the cured film showed an average hardness of 1.05 GPa and a Yong's modulus of 39.18 GPa. Those data imply that the polymer could be used as the varnish for enameled wire, sizing agents for high performance carbon-fiber, and encapsulation resins in microelectronic industry.