Effect of stoichiometric imbalances on the melt condensation polymerization of poly(dodecamethylene terephthalamide) studied by intrinsic viscosity and 13C‐NMR

Poly(dodecamethylene terephthalamide) (PA‐12,T) was synthesized by melt condensation polymerization of 12,T salt with 0, 1, 3, 5, or 10% molar excess of 1,12‐diaminododecane (DA), terephthalic acid (TA), or benzoic acid (BA). Intrinsic viscosities (IV) (0.5 g/dL in 96% H₂SO₄ at 25°C) were measured to determine relative molecular weight differences. IV was highest for reactions containing 1 and 3 mol % excess DA (1.36 and 1.31 dL/g, respectively), followed by the product of pure 1 : 1 salt (1.25 dL/g). For all concentrations of excess TA and BA, IV was decreased. ¹³C‐NMR chemical shifts for DA, TA, and BA end groups were identified and their concentrations determined by comparison with the intensity of main chain polymer peaks. A log–log plot of IV versus number average molecular weight calculated from ¹³C‐NMR data shows a linear trend with Mark‐Houwink constants of K = 55.8 × 10^?5 dL/g and α = 0.81. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Poly(decamethylene terephthalamide) copolymerized with long‐chain alkyl dodecanedioic acid: Toward bio‐based polymer and improved performances

Poly(decamethylene terephthalamide) (PA10T), a bio‐based high‐performance semi‐aromatic polyamide, has been commercialized in recent years. However, there still are some weaknesses restricting its application range, such as narrow melt processing window and low ductility. In this study, we chose dodecanedioic acid (a potential bio‐based raw material) as the comonomer to prepare copolyamides [poly(decamethylene terephthalamide/decamethylene dodecanediamide), PA10T/1012] for solving these problems. The basic properties of these copolyamides were characterized by viscosity measurement, Fourier transform infrared spectrometer, proton nuclear magnetic resonance, wide‐angle X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis, and tensile measurement. Results show that, compared to PA10T, PA10T/1012 exhibits wider melt processing window and more outstanding elongation at break. Meanwhile, PA10T/1012 is still qualified for high temperature resistant material. Furthermore, T_g, T_d,5%, T_d,10%, and T_d,max of PA10T/1012 show a linear dependence on 1012 content, which is helpful to design new bio‐based copolyamides for meeting the needs of various occasions. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46531.     

Synthesis,properties, and biodegradability of three-branched copolyamide (4/6)

Previous studies on polyamide 4, excellent properties, functionalities, and biodegradation in natural condition have been shown. In this study, three-branched (star-shaped) copolyamides constituted of polyamide 4 and polyamide 6 constitutional unit were synthesized by anionic ring-opening copolymerization of 2-pyrrolidone with ε-caprolactam. The thermal and mechanical properties and the biodegradability of the obtained copolyamides have been systematically investigated. The weight-average molecular weight of the copolyamides was as high as tens of thousands (M_w 10–80 × 10³ g/mol). The composition of the copolyamides was approximately in accord with the monomer feed ratio, thereby being controllable. The thermal and mechanical properties changed readily as the composition was varied (T_m 146–266°C, ΔH_m 10–70 J/g, T_d 278–369°C, tensile strength 28–64 MPa, elongation at break 80–750%). The copolyamide having 2-pyrrolidone unit of 96–51 mol% exhibited biodegradability by an activated sludge. The biodegradation of the copolyamide proceeded uniformly without disproportion in constitutional unit.     

Preparation and properties of three novel poly(phosphazene‐aryl amide)s containing cyclotriphosphazene structures

1,1,3,5‐tetraphenoxy‐3,5‐bis(4‐aminoanilino)cyclotriphosphazene, 1,1,3,5‐tetraphenoxy‐3,5‐bis[4‐(4‐aminophenysulfone)anilino)]cyclotriphosphazene, and 1,1,3,5‐tetraphenoxy‐3,5‐bis(N,N′‐ethanediamine)cyclotriphosphazene were synthesized in two steps from the p‐Phenylenediamine, 4,4′‐diaminodiphenylsulfone, and ethylenediamine via nucleophilic substitution and catalytic reduction with hexachlorocyclotriphosphazene. Three novel aromatic polyamides such as poly(cyclotriphosphazene‐p‐phenylene amide), poly(cyclotriphosphazene‐p‐sulfuryl amide), and poly(cyclotriphosphazene‐ethyl amide) were synthesized from these diamines by direct polycondensation reaction with terephthaloyl chloride and pyridine in N‐methyl pyrrolidone, respectively. The chemical structures of the diamine monomers and three novel poly(cyclotriphosphazene‐aryl amide)s were characterized by Fourier Transform Infrared, (¹H and ³¹P) Nuclear Magnetic Resonance, and Elemental Analysis. The thermal properties of the polyamides were determined by Differential Scanning Calorimetry and Thermogravimetric Analysis (TGA). The crystallization behaviors of the polyamides were studied by Wide‐ray X‐ray diffraction, and the morphology of the pyrolysis residues were observed by Scanning Electron Microscope. The three poly(cyclotriphosphazene‐aryl amide)s with amorphous structure would exhibit an enhanced solubility in polar aprotic solvents and a superior thermal stability with initial decomposition temperature being at about 198–259°C. TGA curves of the poly(cyclotriphosphazene‐aryl amide)s exhibit mainly three thermal decomposition steps, and the poly(cyclotriphosphazene‐p‐phenylene amide) presents the highest solid residue rate 62.6% heated to 600°C. In the morphology analysis of the poly(cyclotriphosphazene‐aryl amide) solid residues, organophosphorus gelatum forms in the surface layer were observed. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis of polyundecamethylene 2,6‐naphthalamide as semiaromatic polyamide‐containing naphthalene ring

A novel engineering plastic polyundecamethylene 2,6‐naphthalamide (PA11N) was prepared via a reaction of 2,6‐naphthalene dicarboxylic acid and 1,11‐undecanediamine through a three‐step procedure. The structure of synthesized PA11N was characterized by elemental analysis, Fourier transform infrared spectroscopy, and proton nuclear magnetic resonance (¹H‐NMR). The thermal behaviors were determined by differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analysis. The solubility, water‐absorbing capacity, and mechanical properties of PA11N have also been investigated. Melting temperature (T_m), glass transition temperature (T_g), and decomposition temperature (T_d) of PA11N are 294, 139, and 493°C, respectively. The results show that the heat resistance and mechanical properties of PA11N are near to those of polynonamethylene terephthalamide, and PA11N is a promising heat‐resistant and processable engineering plastic. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Thermal decomposition of poly(tetramethyloxydisilaethylene)

Thermal decomposition of poly[oxybis(dimethylsilylene)] having chains terminated with trimethylsiloxy groups was studied by thermogravimetry, pyrolysis-mass spectrometry, and infrared spectroscopy. The polymer is thermally less stable than poly(dimethylsiloxane). Depolymerization occurs at temperatures of 250–350°C, although this process also takes place at lower temperatures. The depolymerization produces cyclic oligomers of general formula [(Me₂Si)₂O] _n , with predominant formation of the oligomern=2. The depolymerization is accompanied by processes which are referred to as restructurization because they change the structure of the polymer backbone. Decomposition may lead also to the formation of branching points. The shape of the thermograms taken under isothermal conditions is in agreement with an unzipping mechanism for depolymerization involving random initiation. Excluding the short initial period of the process, the unzipping is terminated at a restructurization point. A low activation energy points to initiation induced by electron transfer, presumably involving traces of contaminant. At higher temperatures, 350–600°C, loss of organic parts of the polymer takes place along with further restructurization. At higher temperatures the polymer was also found to undergo easily oxygenation of its backbone with atmospheric oxygen, which leads to the formation of siloxane groups.     

Dynamic mechanical and thermal properties of plasticized poly(lactic acid)

The blends of low molecular weight triacetin (TAC) and oligomeric poly(1,3‐butylene glycol adipate) (PBGA) were used as multiple plasticizers to lubricate poly(lactic acid) (PLA) in this study. The thermal and mechanical properties of plasticized polymers were investigated by means of dynamic mechanical analysis and differential scanning calorimetry. Atomic force microscopy (AFM) was used to analyze the morphologies of the blends. Multiple plasticizers were effective in lowering the glass transition temperature (T_g) and the melting temperature (T_m) of PLA. Moreover, crystallinity of PLA increased with increasing the content of multiple plasticizers. Tensile strength of the blends decreased following the increasing of the plasticizers, but increased in elongation at break. AFM topographic images showed that the multiple plasticizers dispersed between interfibrillar regions. Moreover, the fibrillar crystallite formed the quasicrosslinkings, which is another cause for the increase in elongation at break. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1583–1590, 2006     

Synthesis of soluble and thermally stable polyamides from diamine containing (quinolin‐8‐yloxy) aniline pendant group

A novel diamine monomer having pendant 4‐(quinolin‐8‐yloxy) aniline group was successfully synthesized via aromatic substitution reaction of 8‐quinolinol with p‐fluoronitrobenzene followed by Pd/C catalyzed hydrazine reduction, amidation reaction between 4‐(quinolin‐8‐yloxy) aniline and 3,5‐dinitrobenzoylcholoride followed by Pd/C catalyzed hydrazine reduction. The diamine monomer was fully characterized by using FTIR, ¹H‐NMR, ¹³C‐NMR, and elemental analysis. The diamine monomer was polymerized with various aromatic and aliphatic dicarboxylic acids to obtain the corresponding polyamides. The polyamides had inherent viscosity in the range of 0.30–0.41 dL/g and exhibited excellent solubility in the polar aprotic solvents such as DMAc, NMP, N,N‐dimethylformamide, Pyridine, and DMSO. The glass transition temperatures (T_g) of the polymers are high (up to 313°C) and the decomposition temperatures (T_i) range between 200 and 370°C, depending on the diacids residue in the polymers backbone. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and crosslinking behavior of a soluble,crosslinkable, and high young modulus poly(arylene ether nitriles) with pendant phthalonitriles

Poly(arylene ether nitriles) (PEN) with pendant phthalonitrile groups (PEN? CN) were obtained via the Yamazaki‐Higashi phosphorylation route of 4‐(4‐aminophenoxy)phthalonitrile (APN) with acid‐contained PEN (PEN? COOH) in the presence of CaCl₂. The chemical structure and molecular weight of PEN? CN were characterized by ¹H‐NMR, Fourier transform infrared spectroscopy, and Gel permeation chromatography. The synthesized PEN? CN had superior solubility in polar organic solvent and can be easily processed into thin films from the solutions of N‐methylpyrrolidone, dimethylsulfoxide, N,N′‐dimethylformamide, dimethylacetamide, and tetrahydrofuran. Compared with PEN? COOH, PEN? CN showed higher thermal stability with 5% weight loss temperatures (T_5%) up to 430°C. The glass transition temperature of PEN? CN was improved from 211 to 235°C measured by differential scanning calorimetry (DSC). In addition, it also exhibited excellent mechanical properties that Young's modulus reached to 3.5 GPa. Meanwhile, the effects of different aromatic amines and Lewis acid on the crosslinking behavior of PEN? CN were investigated by DSC. The results indicated that anhydrous Zinc chloride (ZnCl₂) was the best catalyst to lower the curing temperature among 2,6‐bis(4‐diaminobenzoxy) benzonitrile, 4,4‐diaminediphenyl sulfone, APN and ZnCl₂. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis,structure, and physical properties of poly(trimethylene terephthalate)-block-poly(caprolactone) copolymers

The series of poly(trimethylene terephthalate)-block-PCLT (PTT-block-PCLT) copolymers with different contents of PTT as rigid, and poly(caprolactone) (PCL) as flexible segments have been synthesized from dimethyl terephthalate (DMT), 1,3-bio-propanediol, and PCL diol) in a two-step process involving transesterification and polycondensation in the melt. The weight amount of flexible PCLT segments varied from 0 (homopolymer PTT), 25, 35 to 45%. The molecular structure of the synthesized copolymers was confirmed by nuclear magnetic resonance and Fourier transform infrared spectroscopy analyses. According to Hoy's method, one confirmed that PTT and PCL are likely miscible, as the difference of the solubility parameters of PTT and PCL block pairs, equals to 3.15 MPa^1/2. Moreover, the phase structure and mutual miscibility for the series of PTT-block-PCLT copolymers was characterized by differential scanning calorimetry, dynamic mechanical thermal analysis, and wide-angle X-ray scattering measurements. In copolymers with 35 and 45 wt % of flexible segments, the crystalline phase is formed during annealing above glass-transition temperature of copolymer. These copolymers during cooling at the standard rate do not crystallize. It was also found that incorporation of PCLT flexible segments, due to the macrophase separated structure, cause the decrease of the melting point and glass-transition temperature, along with the tensile modulus and tensile strength of PTT-block-PCLT copolymers, and at the same time cause an increase in the value of the elongation at break. As a result of copolymerization of PTT with PCLT, one obtained multiblock copolymers with a heterophase structure. By changing the PTT/PCLT ratio, one obtained copolymers that differ in hardness and tensile strength. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47341.     

Mechanical and thermal properties of dimer acid based nylon 636/Nylon 66 copolymers

Dimer acid (DA)‐based nylon 636/nylon 66 copolymers were synthesized by in situ polymerization. The effects of incorporating nylon 66 on the mechanical and thermal properties were characterized by means of intrinsic viscosity determination, attenuated total reflection (ATR)–Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), differential scanning calorimetry, thermogravimetric analysis, and mechanical testing. The results show that the intrinsic viscosity of the copolymers ranged from 1.0 to 2.1 dL/g, depending on the content of nylon 66. The incorporation of nylon 66 into DA‐based nylon 636 had no significant effect on the values of the glass‐transition temperature, melting temperature, temperature at 50% weight loss, or temperature at the maximum rate of decomposition, but the crystallization temperature, crystallinity degree, and extrapolated onset temperature increased. ATR–FTIR spectroscopy and XRD demonstrated that with increasing nylon 66 mass, the content of α‐ and β‐crystal forms would increase accordingly. The mechanical test data revealed that with increasing nylon 66 concentration, the tensile strength of the copolymers increased, and the flexural strength and flexural modulus first increased and then decreased. However, the notched Izod impact strength decreased. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39845.     

嵌段聚醚酯弹性纤维的老化及热分解

通过测定以PBT为硬段 ,聚乙二醇 (PEG)和聚丁二醇 (PTMG)为软段的嵌段聚醚酯弹性纤维在老化前后的特性粘数、断裂强度、断裂伸长率和弹性回复率的变化 ,发现添加抗氧剂能明显改善该弹性纤维的抗老化性能并提高纤维的力学性能和回弹性能 ;采用热失重测定了PBT -PTMG2嵌段聚醚酯弹性纤维的热分解性能 ,热分解动力学计算表明其热分解活化能较低 ,为 69.6kJ ,容易热分解 ,热分解为 1级反应     

Semiaromatic polyamide poly(hexamethylene terephthalamide)‐co‐polycaprolactam: Thermal and flame‐retardant properties

The poly(hexamethylene terephthalamide)‐co‐polycaprolactam (PA6T/6; 50:50) copolymer was synthesized with a reactive extrusion method and subsequently mixed with a certain content of glass fibers (GFs) and different ratios of flame‐retardant aluminum diethyl phosphinate (AlPi) to fabricate a series of composites. These resulting composites were found to have excellent mechanical (tensile strength = 119–154 MPa) and thermal properties (heat‐deflection temperature = 263–293 °C). It is particularly worth mentioning that the value of the limiting oxygen index reached 29.5% and a UL‐94 V‐0 rating (1.6 mm) was achieved with the addition of 20 portions of AlPi. Also, the values of the peak heat‐release rate and total heat release in cone calorimetry were found to decrease with the addition of the flame‐retardant AlPi, which acted mainly as a flame inhibitor in the gas phase. Through visual observation, scanning electron microscopy after cone calorimetry testing, and thermogravimetric analysis, the condensed‐phase flame‐retardant mechanism of the PA6T/6–GF–AlPi system was confirmed to have a synergetic role. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46451.     

Morphology,thermal and mechanical properties of glass fiber‐reinforced crosslinkable poly(arylene ether nitrile)

Crosslinkable poly(arylene ether nitrile)/glass fiber (PEN/GF) composites with high thermal stabilities and mechanical properties were prepared by a economically and environmentally viable method of melt extrusion and injection molding. The feasibility of using PEN/GF composites was investigated by evaluating its morphological, rheological, thermal, and mechanical properties. The morphology shows a good dispersion and strong interfacial interaction between PEN and GF. Thermal studies reveal that the thermal stabilities of PEN/GF are improved significantly with increase of GF content. Mechanical investigation manifested that GFs have strengthening effect (increase in flexural, tensile, and impact strength) on the mechanical performance of PEN composites. Most importantly, crosslinking reaction of PEN/GF composites can further improve their mechanical performances, because a couple of GFs are agglomerated by thermal motion and strong interfacial adhesion and the local agglomeration does not break the global uniform distribution. This work shows that both the enhancement of GF content and the crosslinking reaction of PEN/GF composites are two key factors influencing the thermal and mechanical properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and characterisation of branched and partially crosslinked poly(ethylene terephthalate)

In the present study, a series of branched and partially crosslinked poly(ethylene terephthalate) (PET) samples were prepared by the two‐stage melt polycondensation method, using different amounts of trimethyl trimellitate (TMT) as polyfunctional monomer. The samples were characterised with respect to intrinsic viscosity, density and gel content as well as thermal and mechanical properties. The intrinsic viscosity of the polymers ranged between 0.7 and 1.6 dl g^?1 depending on the concentration of the TMT comonomer. When TMT was used at a concentration 0.625 wt% or higher, gel formation was observed. For the sample containing 1.25 wt% TMT, almost half of the polymer was insoluble in phenol–tetrachloroethane mixture, due to extensive crosslinking. The increase of TMT content resulted in a small decrease of crystallinity attributed to branching and crosslinking, both of which restrict the organisation of the polymer chains in the crystal structure. This was reflected directly in the thermal properties of the polymers prepared. Increasing the TMT content decreased the melting point and the heat of fusion. In contrast, cold crystallization and glass transition temperatures were shifted to higher temperatures. Mechanical properties like tensile strength and elongation at break increased with increasing the content in branching agent. However, crosslinking had a negative effect on elongation at break. Copyright © 2003 Society of Chemical Industry     

Solid state polymerization in a micro‐reactor: The case of poly(tetramethylene terephthalamide)

The aim of this work was to develop and optimize a direct solid state polymerization (DSSP) process on a micro scale for alkyldiammonium‐terephthalate salts. This was successfully demonstrated for the first time by the case of tetramethylenediammonium‐terepththalate salt (4T salt). The derived polymer (PA4T) presents interesting properties, but the temperature‐favored acid catalyzed cyclization of tetramethylenediamine (TMD) to mono‐functional pyrrolidine and ammonia inhibits a high polymerization conversion. DSSP was performed in a thermogravimetrical analysis (TGA) chamber, and the continuously monitored weight loss was correlated to polymerization conversion via the release of water, excluding any mass and heat transfer limitations. It was found that the conditions under which the DSSP is performed and the morphology of the starting material affect both the reaction rate and the product quality. The effect of the critical process parameters, namely vent size, heating rate to reach SSP temperature, and reaction temperature were quantified by the observed mass loss and by ¹H NMR analysis. It was noticed that, besides the water formed by amidation, other volatile compounds were also released during the DSSP reaction, with main component, the TMD. In particular, it was observed that conditions favoring the evaporation of TMD also favored a higher reaction rate. The TMD loss was minimized by optimization of the aforementioned process conditions, leading to a more thermally stable and a higher molecular weight final product. The thermal stability of the PA4T was found to be inversely correlated to the concentration of carboxylic end groups present in the formed polymer. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43271.     

Characterization of the mechanical and thermal properties and morphological behavior of biodegradable poly(L‐lactide)/poly(ε‐caprolactone) and poly(L‐lactide)/poly(butylene succinate‐co‐L‐lactate) polymeric blends

Two series of biodegradable polymer blends were prepared from combinations of poly(L ‐lactide) (PLLA) with poly(?‐caprolactone) (PCL) and poly(butylene succinate‐co‐L ‐lactate) (PBSL) in proportions of 100/0, 90/10, 80/20, and 70/30 (based on the weight percentage). Their mechanical properties were investigated and related to their morphologies. The thermal properties, Fourier transform infrared spectroscopy, and melt flow index analysis of the binary blends and virgin polymers were then evaluated. The addition of PCL and PBSL to PLLA reduced the tensile strength and Young's modulus, whereas the elongation at break and melt flow index increased. The stress–strain curve showed that the blending of PLLA with ductile PCL and PBSL improved the toughness and increased the thermal stability of the blended polymers. A morphological analysis of the PLLA and the PLLA blends revealed that all the PLLA/PCL and PLLA/PBSL blends were immiscible with the PCL and PBSL phases finely dispersed in the PLLA‐rich phase. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of poly(siloxane-urethane)s

A series of polyurethane block copolymers based on hydroxy-terminated polydimethylsiloxane and poly(propylene glycol) soft segments of molecular weights 1818 and 2000, respectively, were synthesized. The hard segments consisted of 4,4′-diphenylnethane diisocyanate and 1,4-butanediol as the chain extender. Samples with different molar ratios were prepared. We tried to synthesize polydimethylsiloxane-based polyurethanes (PDMS-PU) containing a hard block as major fraction and a soft block as minor fraction for preparing toughened rigid systems. After a study of the pure polydimethylsiloxane-based polyurethane and poly(propylene glycol)-based polyurethane (PPG-PU), (mixed polyol)-based block copolymers and blends of PDMS-PU and PPG-PU were synthesized, and characterized by means of differential scanning calorimetry, tensile testing and scanning electron microscopy. In (mixed polyol)-based copolymers and lower hard-segment content blends, macro-phase separation occurred, but blends with higher hard-segment contents showed significant reduction in amounts of phase separation.     

Preparation and properties of poly(benzyl glutamate)–poloxamer–poly(benzyl glutamate) and poly(glutamic acid)–poloxamer–poly(glutamic acid) triblock polymers

The novel block copolymer poly(benzyl glutamate) (PBLG)–polomamer–PBLG were synthesized from glutamic acid and poloxamer in six steps with three different molecular weights, and another new block copolymer, poly(glutamic acid) (PGA)–poloxamer–PGA, was obtained by the benzyl deprotection of PBLG–poloxamer–PBLG. The obtained compounds were characterized by IR spectroscopy, gel permeation chromatography, and ¹H‐NMR. The in vitro biological degradation and water absorption of PBLG showed that a greater proportion of PBLG in the copolymer led to a slower degradation and weaker water absorption, so the speed of degradation and water absorption could be adjusted through adjustment of the ratio of poloxamer. Both PBLG–poloxamer–PBLG and PGA–poloxamer–PGA exhibited lower cytotoxicity and good biocompatibility in the methyl thiazolyl tetrazolium (MTT) assay. The results show that both block polymers are promising as drug‐carrier materials. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Improving the thermal and mechanical properties of poly(arylene ether nitrile) films through blending high- and low-molecular-weight polymers

In present work, novel phthalonitrile end-capping poly(arylene ether nitrile)-phenyl (PEN-Ph) films with excellent mechanical properties as well as high glass transition temperature were prepared through blending high-molecular-weight PEN-Ph (HMW PEN-Ph) and low-molecular-weight PEN-Ph (LMW PEN-Ph). Then, the thermal and mechanical properties of the samples with different mass ratio of HMW PEN-Ph and LMW PEN-Ph were studied, and the effect of heat-treatment temperature on the performance of films was also investigated. The analysis results indicate that the crosslinking density as well as film formation can be controlled by adjusting the mass ratio of HMW PEN-Ph to LMW PEN-Ph. Besides, when the mass ratio of HMW PEN-Ph to LMW PEN-Ph is 5:2, the film treated at 340 °C possesses the best thermal and mechanical properties, with T_g of 218.9 °C and tensile strength of 104.8 MPa, increased by 10.9 °C and 16.6 MPa than pure HMW PEN-Ph film, respectively. Thus, the presence of LMW PEN-Ph makes the thermal and mechanical properties of the films improve dramatically, providing the possibility for the application in the electronics and high-temperature resistant fields. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48457.