Synthesis of fluorinated polyimides and their application to passive optical waveguides

Fluorinated and chlorofluorinated polyimides with high thermal stability and low optical absorption loss in the optical communication wavelengths of 1.3 and 1.55 μm were investigated for low‐loss passive waveguide applications. These polyimides were prepared from pyromellitic dianhydride (PMDA) with 1,4‐bis‐[4‐amino‐2‐(trifluoromethyl)phenoxy]tetrafluorobenzene (ATPT), 1,4‐bis‐[4‐amino‐2‐(trifluoromethyl)phenoxy]benzene (ATPB), and 1,3‐bis‐[4‐amino‐2‐(trifluoromethyl)phenoxy]‐4,6‐dichlorobenzene (ATPD). Control of the refractive indices of the polymers was achieved from 1.5397–1.5671 for TE polarization and 1.5239–1.5513 for TM polarization at 1.55 μm by copolymerization of PMDA/ATPT and PMDA/ATPB. As the amount of PMDA/ATPT was increased, the refractive indices of the polymers were decreased. Rib‐type optical waveguides were fabricated using these fluorinated polyimides. These waveguides exhibited a low propagation loss of less than 0.5 dB/cm at 1.55 μm. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2172–2177, 2000     

Synthesis and properties of organosoluble polyimides derived from 2,2′‐dibromo‐ and 2,2′,6,6′‐tetrabromo‐4,4′‐oxydianilines

Two new aromatic diamines, 2,2′‐dibromo‐4,4′‐oxydianiline (DB‐ODA 4 ) and 2,2′,6,6′‐tetrabromo‐4,4′‐oxydianiline (TB‐ODA 5 ), have been synthesized by oxidation, bromination, and reduction of 4,4′‐oxydianiline (4,4′‐ODA). Novel polyimides 6a–f and 7a–f were prepared by reacting DB‐ODA ( 4 ) and TB‐ODA ( 5 ) with several dianhydrides by one‐step method, respectively. The inherent viscosities of these polyimides ranged from 0.31 to 0.99 dL/g (0.5 g/dL, in NMP at 30°C). These polyimides showed enhanced solubilities compared to those derived from 4,4′‐oxydianiline and corresponding dianhydrides. Especially, polyimides 7a , derived from rigid PMDA and TB‐ODA ( 5 ) can also be soluble in THF, DMF, DMAc, DMSO, and NMP. These polyimides also exhibited good thermal stability. Their glass transition temperatures measured by thermal mechanical analysis (TMA) ranged from 251 to 328°C. When the same dianhydrides were used, polyimides 7 containing four bromide substituents had higher glass transition temperatures than polyimides 6 containing two bromide substituents. The effects of incorporating more polarizable bromides on the refractive indices of polyimides were also investigated. The average refractive indices (n_av) measured at 633 nm were from 1.6088 to 1.7072, and the in‐plane/out‐of‐plane birefringences (Δn) were from 0.0098 to 0.0445. It was found that the refractive indices are slightly higher when polyimides contain more bromides. However, this effect is not very obvious. It might be due to loose chain packing resulted from bromide substituents at the 2,2′ and 2,2′,6,6′ positions of the oxydiphenylene moieties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation of large‐sized graded‐index polymer preform

In this article, an improved method was put forward to overcome the defect of interfacial‐gel polymerization technique. The cause of the defects was analyzed, and the factors of reaction conditions on formation of the graded‐index (GI) polymer preform (i.e., reaction temperature and atmosphere pressure) were investigated. High‐performance large‐sized GI polymer preform was prepared by this improved technique, in which diphenyl sulfide was used as higher refractive index molecules. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 817–820, 2003     

Synthesis of new alicyclic polyimides by Diels‐Alder polymerization

Four new alicyclic poly{arylene‐9,10‐di[4‐(methyloxy)phenyloxy]‐1,2,3,4,5,6,7,8‐octahydroanthracene‐2,3,6,7‐tetracarboxdiimide}s (APIs) were prepared at 80°C in the presence of NaI in DMSO by the in situ Diels‐Alder polymerization of 1,4‐bis[4‐(methyloxy)phenyloxy]‐2,3,6,7‐tetrakis(bromomethyl)benzene (MPBB) with four arylenebismaleimides (AMIs). The stereochemical isomerisms measured for the model compound DPAI and MDA‐PI by HETCOR spectroscopy and ¹H‐NMR spectroscopy, respectively, revealed that DPAI and APIs presumably have only one trans‐bis‐endo‐configuration. Inherent viscosities of APIs varied in the 0.20–0.41 dL/g range. Solubility tests revealed that in spite of the alicyclic units incorporated the APIs were only marginally soluble in polar organic solvents. In TGA in N₂ the APIs began to decompose at temperatures higher than 380°C, revealing two‐step pyrolysis behavior. 4‐(Methyloxy)phenyloxy side groups were believed to degrade in the lower temperature range. In DSC and wide‐angle X‐ray diffractometry APIs all appeared completely amorphous and in UV‐Vis spectroscopy both DPAI and APIs were transparent at wavelengths longer than 375 nm. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis and characterization of partly fluorinated poly(phthalazinone ether)s crosslinked by allyl group for passive optical waveguides

It is necessary to introduce cross-linkable groups onto polymer chains as the processability and thermal stability of the polymers for passive waveguide device applications are very dependent on their cross-linking capabilities. Herein a series of novel cross-linkable allyl-containing fluorinated poly(phthalazinone ether)s (Allyl-FPPEs) have been prepared by a modified polycondensation of 4-(4-hydroxylphenyl)(2H)-phthalazin-1-one (DHPZ), decafluorobiphenyl (DFBP), 4,4′-(hexafluoroisopropylidene)diphenol (6F-BPA), and 3,3′-diallyl-4,4′-dihydroxybiphenyl (DA-DHBP) for optical waveguide applications. The obtained random polymers were characterized by FT-IR, NMR and GPC. The resulting polymers having good solubility in polar organic solvents at room temperature, can be easily spin-coated into thin films with attracting optical quality, good thermal stabilities (the temperatures of 1% mass-loss after curing: 455-503 °C), and high glass transition temperatures (T_gs: 167-251 °C) which could further increase by about 20 °C after thermal cross-linking. The crosslinked polymer films exhibit good optical properties. By adjusting the feed ratio of the reactants, the refractive indices of TE and TM modes (at 1550 nm) could be well controlled in the range of 1.4998-1.5618 and 1.4954-1.5520, respectively. The optical losses of the crosslinked polymers possess rather low values, less than 0.3 dB/cm at 1550 nm.     

Organosoluble,low‐dielectric‐constant fluorinated polyimides based on 9,9‐bis[4‐(4‐amino‐2‐trifluoromethyl‐ phenoxy)phenyl]xanthene

A new trifluoromethylated bis(ether amine) monomer, 9,9‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]xanthene (BATFPX), was prepared through the nucleophilic aromatic substitution reaction of 2‐chloro‐5‐nitrobenzotrifluoride and 9,9‐bis(4‐hydroxyphenyl)xanthene in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C in ethanol. A series of novel fluorinated polyimides were synthesized from BATFPX with various commercially available aromatic tetracarboxylic dianhydrides by one‐step polycondensation in m‐cresol. The resulting polyimides were readily soluble in many organic solvents such as N,N‐dimethylacetamide and tetrahydrofuran, and afforded transparent, flexible and strong films with low moisture absorption (0.28–0.51%), low dielectric constant (2.85–3.26 at 1 MHz) and good optical transparency with UV‐visible absorption cut‐off wavelengths at 352–410 nm. All the polyimides were amorphous and exhibited high thermal stability, with glass transition temperatures of 282–330 °C, 5% weight loss temperatures above 520 °C in nitrogen or air and char yields higher than 55% at 800 °C in nitrogen. Also, these polyimides had good mechanical properties with tensile strengths of 93–118 MPa, elongations at break of 9–16% and initial moduli of 2.07–2.58 GPa. Copyright © 2011 Society of Chemical Industry     

Synthesis and structure–property relationships of novel thiazole‐containing poly(amide imide)s with high refractive indices and low birefringences

The primary objective of this study was to investigate the structure–property relationships in high‐performance polymers with high refractive indices and low birefringences. A series of novel poly(amide imide)s (PAIs) were synthesized from a thiazole‐containing diimide–diacid monomer and various aromatic diamines. The influence of the pendant phenyl substituents on the optical properties of these PAIs was studied by comparison with the analogous polymers containing methyl groups. The PAIs exhibited excellent solubility and good thermal stability. The optical transmittances of the PAI films at 450 nm were higher than 75%. The combination of the thiazole units, thioether linkages and pendant phenyl rings provided the PAIs with high average refractive indices of 1.7361–1.7536 and low birefringences of 0.0066–0.0097 at 632.8 nm. © 2014 Society of Chemical Industry     

Evaluation of halogenated polyimide etching for optical waveguide fabrication by using inductively coupled plasma

Oxygen plasma etching of a series of halogenated polyimides was carried out for low‐loss waveguide fabrication by using inductively coupled plasma (ICP). The effects of etching parameters such as ICP power, rf power, and O₂ flow rate on the etching rate and etching profile of polymer films were investigated. The increase in the etch rate with the ICP power and the rf power was observed. Both the vertical profile and sidewall roughness were found to be related to the ion energy (dc bias). By optimizing these parameters, a vertical profile and a smooth sidewall were obtained by 500 W of ICP power, 150 W of rf power, 5 mTorr of chamber pressure, and 40 sccm of the O₂ flow rate. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 176–182, 2001     

Fabrication and characterization of planar and channel polymer waveguides. II. Poly(p‐phenylene benzobisthiazole) (PBZT) films

Solutions of poly(p‐phenylene benzobisthiazole) (PBZT) in methane sulfonic acid (MSA) were prepared and studied. Solutions with concentrations less than 0.04 wt % PBZT were characterized by dilute solution viscometry. Planar PBZT waveguides were spin‐coated from a 0.5 wt % PBZT solution onto oxidized silicon wafers. The optical attentuation of the resulting polymer waveguides was measured and found to depend on both the thickness of the oxide layer on the silicon substrate and also the wavelength of the incident light. The lowest optical loss recorded for PBZT in this investigation was 4.81 ± 1.39 dB/cm at 834 nm. This work thus demonstrates the successful fabrication of PBZT into thin‐film planar waveguides. The PBZT films prepared here also show improved optical characteristics over PBZT films prepared previously by either extrusion or spin coating. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1448–1456, 2000     

Synthesis and characterization of ternary‐copolymer of soluble fluorinated polyimides based on 1,4‐bis (4‐amino‐2‐trifluoromethylphenoxy) benzene

A series of novel ternary‐copolymer of fluorinated polyimides (PIs) were prepared from 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzene (pBATB), commercially available aromatic dianhydrides, and aromatic diamines via a conventional two‐step thermal or chemical imidization method. The structures of all the obtained PIs were characterized with FTIR, ¹H‐NMR, and element analysis. Besides, the solubility, thermal stability, mechanical properties, and moisture uptakes of the PIs were investigated. The weight‐average molecular weight (M_w) and the number‐average molecular weight (M_n) of the PIs were determined using gel‐permeation chromatography (GPC). The PIs were readily dissolved not only in polar solvents such as DMF, DMAc, and NMP, but also in some common organic solvents, such as acetic ester, chloroform, and acetone. The glass transition temperatures of these PIs ranged from 201 to 234°C and the 10% weight loss temperatures ranged from 507 to 541°C in nitrogen. Meanwhile, all the PIs left around 50% residual even at 800°C in nitrogen. The GPC results indicated that the PIs possessed moderate‐to‐high number‐average molecular weight (M_n), ranging from 9609 to 17,628. Moreover, the polymer films exhibited good mechanical properties, with elongations at break of 8–21%, tensile strength of 66.5–89.8 MPa, and Young's modulus of 1.04–1.27 GPa, and low moisture uptakes of 0.54–1.13%. These excellent combination properties ensure that the polymer could be considered as potential candidates for photoelectric and microelectronic applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Functionalized N‐(4‐hydroxy phenyl) maleimide monomers: Kinetics of thermal polymerization and degradation using model‐free approach

N‐(4‐Hydroxy phenyl) maleimide (HPMI) is prepared and is functionalized with acryloyl, methacryloyl, allyl, propargyl, and cyanate groups. The structural and thermal characterizations of the materials are done using FTIR, NMR, DSC, and TGA. Curing and degradation kinetics are performed using Flynn–Wall–Ozawa, Vyazovkin, and Friedman methods. Activation energies (E_a) for the polymerization of the synthesized monomers varied and are dependent on the nature of the functional group present in HPMI. The propargyl functionalized monomer shows the highest E_a values whereas the methacryloyl functionalized monomer shows the lowest E_a values. In the case of thermal degradation of the polymerized materials, the apparent E_a values for acryloyl, methacryloyl and cyanate functionalized materials are slightly higher than that of poly‐HPMI (PHPMI). The thermally cured allyl and propargyl functionalized materials show a different trend and may be attributed to the complications arising due to Claisen rearrangement reaction during the thermal curing. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39935.     

Synthesis and characterization of novel photo‐crosslinkable fluorinated poly(phthalazinone ether)s for optical waveguides

A series of novel photo‐crosslinkable fluorinated poly(phthalazinone ether)s containing 1,1‐diphenylethylene segments in the polymer main chain, used for optical waveguide materials, were synthesized by polycondensation reaction of decafluorobiphenyl with a mixture of 4‐(4‐hydroxylphenyl)(2H)‐phthalazin‐1‐one (DHPZ), 4,4‐(hexafluoroisopropylidene)diphenol and 1,1‐bis(4‐hydroxyphenyl)ethylene (BHPE) as co‐reactant. The feed ratio of DHPZ to total bisphenols varied from 0 to 80 mol%, while that of BHPE remained at 20 mol% for all polymers. The obtained copolymers show good solubility in some common polar organic solvents. The resulting polymers were photo‐crosslinked after UV irradiation for 10 min in the presence of a photoinitiator. The cured polymers show good chemical resistance, high thermal stability (temperatures of 1% mass loss after curing of 472–496 °C under nitrogen) and high glass transition temperatures (160–249 °C) which could be further increased by about 10 °C after photochemical crosslinking. By adjusting the copolymerizing bisphenol content, the refractive indices of transverse electric and transverse magnetic modes (at 1550 nm) of films of the polymers were exactly tuned in the range 1.5029–1.5661 and 1.4950–1.5502, respectively. The propagation losses of the cured films were measured and found to be less than 0.3 dB cm^?1 at 1550 nm, indicating the promise of these materials for passive optical waveguide devices. Copyright © 2011 Society of Chemical Industry     

Thermal stability of end‐capped and linear sulfonated polyimides,sulfonated polystyrene,and Nafion 117

The thermal stability of end‐caped and linear sulfonated polyimides (SPIs), sulfonated polystyrene (SPS), and a sulfonated perfluorinated hydrocarbon, Nafion 117, and the corresponding triethylammonium sulfonate salts was investigated by dynamic and isothermal thermogravimetric analysis (TGA). Gas chromatographic‐mass spectrographic analysis (GC/MS) of the sulfonated polymers and the salts to determine the volatiles released from acid and salt groups over a temperature range 200–275 °C was also investigated. GC/MS analysis reveals that water and sulfur dioxide volatiles are released from the sulfonic acids and water, sulfur dioxide and triethyl amine are released from the sulfonate salts. Dynamic and isothermal TGA studies based on weight loss revealed that the SPIs exhibited superior thermal stability than SPS and Nafion 117 sulfonic acids. However, dynamic TGA curves to determine the onset decomposition temperature of the sulfonic acid group reveal that Nafion 117 and SPS sulfonic acids exhibited greater thermal stabilities than the SPIs. The mechanisms of sulfonic acid and triethylammonium sulfonate salt decompositions based on GC/MS, ¹³C‐NMR, and dynamic TGA curves are proposed. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45694.     

Graded‐index plastic optical fiber with high mechanical properties enabling easy network installations. II

It was shown how high mechanical strength should be provided in the high numerical aperture (NA) graded‐index plastic optical fiber (GI POF). In this newly developed GI POF, a copolymer of methyl methacrylate (MMA) and 2,2,2‐trifluoroethyl methacrylate (3FMA) was used to increase the NA. The GI POF we proposed previously was composed of a PMMA homopolymer cladding and a doped PMMA core. It was previously shown that substituting the copolymer P(MMA–3FMA) for the PMMA as the cladding material made little change in the fiber's light‐transmission characteristics. This study focused on mechanical flexibility, which is one of the most important advantages of the POF. It was found that the P(MMA–3FMA)‐clad GI POF had almost the same or superior mechanical strength in addition to the excellent light‐propagation characteristics. It was also found that such excellent mechanical properties were achieved using a small dopant concentration and optimum heat‐drawing conditions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 410–416, 2004     

Fabrication of a graded‐index polymer optical fiber preform without cavity via the automatic refilling process

When two monomers with different densities and refractive indices are polymerized under a centrifugal force field, a cavity is generated in the rotational axis as a result of inherent volume shrinkage. Accordingly, an additional monomer‐refilling process is necessary to compensate for the undesirable cavity. In this study, we modified the stepwise refilling process to an automatic process and have successfully fabricated a graded‐index polymer optical fiber preform without a cavity. The process could also reduce the processing time and enhance the transmission speed of a polymer optical fiber compared with the stepwise process. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Organosoluble and light‐colored fluorinated polyimides based on 1,1‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]‐1‐phenylethane and various aromatic dianhydrides

To investigate the CF₃ group affecting the coloration and solubility of polyimides (PI), a novel fluorinated diamine 1,1‐bis[4‐(4‐amino‐2‐ trifluoromethylphenoxy)phenyl]‐1‐phenylethane (2) was prepared from 1,1‐ bis(4‐hydrophenyl)‐1‐phenylethan and 2‐chloro‐5‐nitrobenzotrifluoride. A series of light‐colored and soluble PI 5 were synthesized from 2 and various aromatic dianhydrides 3a–f using a standard two‐stage process with thermal 5a– f(H) and chemical 5a–f(C) imidization of poly(amic acid). The 5 series had inherent viscosities ranging from 0.55 to 0.98 dL/g. Most of 5a–f(H) were soluble in amide‐type solvents, such as N‐methyl‐2‐pyrrolidone (NMP), N,N‐ dimethylacetamide (DMAc), and N,N‐dimethylformamide (DMF), and even soluble in less polar solvents, such as m‐Cresol, Py, Dioxane, THF, and CH₂Cl₂, and the 5(C) series was soluble in all solvents. The GPC data of the 5a–f(C) indicated that the Mn and Mw values were in the range of 5.5–8.7 × 10⁴ and 8.5–10.6 × 10⁴, respectively, and the polydispersity index (PDI) Mw /Mn values were 1.2–1.5. The PI 5 series had excellent mechanical properties. The glass transition temperatures of the 5 series were in the range of 232–276°C, and the 10% weight loss temperatures were at 505–548 °C in nitrogen and 508–532 °C in air, respectively. They left more than 56% char yield at 800°C in nitrogen. These films had cutoff wavelengths between 356.5–411.5 nm, the b* values ranged from 5.0–71.1, the dielectric constants, were 3.11–3.43 (1MHz) and the moisture absorptions were in the range of 011–0.40%. Comparing 5 containing the analogous PI 6 series based on 1,1‐bis[4‐(4‐aminophenoxy)phenyl]‐1‐ phenylethane (BAPPE), the 5 series with the CF₃ group showed lower color intensity, dielectric constants, and better solubility. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2399–2412, 2005     

Chemical modification of 3,3′,4,4′‐biphenyltetracarboxylic dianhydride polyimides by a catechol‐derived bis(ether amine)

Having previously demonstrated that the polyimide derived from 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA) and 1,2‐bis(4‐aminophenoxy)benzene [termed triphenyl ether catechol diamine (TPEC)] exhibited superior tensile properties in addition to good thermal properties, we now provide a preliminary assessment of the properties of the copolyimides prepared from BPDA, TPEC, and another aromatic diamine. The homopolyimides derived from BPDA and many aromatic diamines generally possessed good mechanical properties and thermal properties; however, they were insoluble in available organic solvents. In several cases, organosoluble BPDA copolyimides could be prepared from BPDA and equimolar mixtures of TPEC and another aromatic diamine. All the copolyimides could be formed into tough films with high moduli and strengths and, in most cases, high extensions to break. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 351–358, 2002; DOI 10.1002/app.10342     

Development of halogen‐free flame‐retardant thermoplastic elastomer polymer blend

Ethylene‐propylene diene rubber (EPDM) and isotactic polypropylene (iPP) blends have widest industrial applications that require a degree of flame retardancy. Halogen‐free intumescent technology based on phosphorous salt is a significantly advanced approach to make the polymer flame‐retardant. Both ammonium polyphosphate and ethylenediamine phosphate are important intumescent compounds. Their combination with carbonific and spumific agents were studied in binary blends of EPDM/PP. The polymer system was vulcanized online during melt mixing. Intumescent flame‐retardant polymer systems exhibit good flame‐retardancy with optimum comparable physiomechanical, electrical, and fluid resistance properties, including lower smoke emission, which is essential to protect people because the visibility remains unaffected in the event of fire. Pronounced charring and intumescent effect appear to enhance the flame‐retardancy of the polymers. Possible expected intumescent mechanism is proposed based on the nonpyrolysis mechanism for the flame‐retarded polymer and the intumescent components. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 407–415, 2004     

Graded‐index plastic optical fiber with high mechanical properties enabling easy network installations. I

A doped poly(methyl methacrylate) (PMMA)–based graded‐index plastic optical fiber (GI POF) with high mechanical strength is reported for the first time. Although the POF is generally believed to have a good mechanical flexibility even if it has a large‐core diameter, such a high mechanical strength has been provided by making the polymer chains in the POF highly oriented in its axial direction. If such an orientation of polymer chains is eliminated, the POF becomes brittle, which is similar to silica‐based fibers. On the other hand, too high an orientation of the polymer chains induces fiber deformation in a high‐temperature atmosphere resulting from orientation relaxation. This study reports how high mechanical strengths such as the tensile strength and the large elongation are provided to the GI POF. By selecting the optimum heat‐drawing conditions, the GI POF has a mechanical strength comparable to that of the commercially available step index (SI) POF. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 404–409, 2004     

Low‐temperature synthesis of Mg(OH)2 nanoparticles from MgO as halogen‐free flame retardant for polypropylene

Mg(OH)₂ (MH) nanoparticles were synthesized by hydration of the light‐burned MgO at low temperature (70°C). Effects of additives, such as magnesium nitrate and magnesium acetate, on the size, morphology and agglomeration of MH particles were investigated. MH nanoparticles have platelet‐like structure and approximately 20–40 nm in thicknesses. The supersaturation degree plays an important role in magnesia hydration and is defined. When magnesium acetate was used as the additive, the hydroxyl ion can be homogeneously introduced into the solution. The size and morphology of MH nanoparticles are more homogeneous. Modified by titanate coupling agent, MH nanoparticles were used as the flame retardant for polypropylene (PP). The combustibility, mechanical properties and thermal behaviors of the PP/MH composites were characterized. The mechanical properties of PP/MH composites are not seriously deteriorated with increasing MH content. When the amount of MH fraction reached 65, the limiting oxygen index (LOI) value and UL 94 testing result of MH65 are 33.8 and V‐0 grading, respectively. The onset temperature (T_10%) and the maximum thermal decomposition temperature (T_max) of MH65 separately increased by approximately 100°C and 77°C than those of neat PP. Copyright © 2012 John Wiley & Sons, Ltd.