JOURNAL OF APPLIED POLYMER SCIENCE
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2020
·Vol. 138
·期 1
·49640
·
IF 2.52
Chunyan Qu,Yao Tang,Dezhi Wang,XuPeng Fan,Hongfeng Li,Changwei Liu,Kai Su,Daoxiang Zhao,Jiaqi Jing,Xiao Zhang
Limitations in the properties of polyamide PA66, such as low glass transition temperature and high water absorptivity, limit its applications. Introduction of amorphous polyimide segments into the PA66 main chain lowers the glass transition temperature and melting temperature and also improves its processability. PA66-polyimide (PA-PI) copolymers with different weight ratios of PI are prepared by high temperature and high-pressure solution polymerization. The degree of crystallization of PA-PI copolymers decreases with increasing PI content. The melting point decreases from 261°C for PA66 to 223°C for PA-PI-4. Dynamic mechanical analysis shows that the T g increases from 70 to 90°C, and the storage modulus can be well maintained. Rheological studies show that the temperature for processing can reach 70°C. Copolymers with different PI contents show different processing viscosities. In addition, water absorptivity (about 1.8%) and dielectric constant values of PA-PI and PA6/6T are similar.
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2020
·Vol. 138
·期 6
·49792
·
IF 2.52
Rui Yang,Boran Hao,Lin Sun,Kan Zhang
In this study, an amide functionalized bis-benzoxazine (AI-al) has been synthesized using allylamine, ortho -amide functional bis-phenol and paraformaldehyde as raw materials via Mannich condensation. This newly obtained benzoxazine has been used to react with polydimethylsiloxane (PDMS) through hydrosilylation to form poly(benzoxazine- co -amide- co -siloxane) (AI-al-PDMS) featuring siloxane, amide and benzoxazine as repeating units. The chemical structures of both oxazine ring-containing monomer and copolymer are confirmed by NMR and FT-IR spectroscopies. Besides, the thermally activated polymerization behaviors of AI-al and AI-al-PDMS are investigated by DSC, and the subsequent conversion of benzoxazole formation is studied by in situ FT-IR. Moreover, dynamic mechanical analysis and thermogravimetric analysis are used to determine the thermal properties of the cross-linked polymers. The resulting cross-linked poly(benzoxazole- co -siloxane) derived from AI-al-PDMS shows excellent thermal stability (no T g can be observed before 400°C; Td5 of 393°C) and low dielectric constants (2.52–2.13 in the frequency range of 1 Hz to 1 MHz), evidencing its great potential applications in electronic packing, aerospace, and other high-performance fields.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 138
·期 2
·49667
·
IF 2.52
Mengting Li,Changgui Li,You Zhou,Hua Tian,Qiaoyuan Deng,Haifang Liu,Li Zhu,Xueqiong Yin
Microencapsulation is a widely-investigated technique used for the unstable material preservation since the wall materials prevent the core materials from loss and deterioration. To improve the stability of cinnamaldehyde (CAL), different microcapsule wall systems are fabricated by spray-drying, and then characterized by experimental methods to determine the most suitable wall materials. Surface morphology, encapsulation efficiency, effective loading capacity, as well as moisture absorption property are evaluated, and the results suggest that a three-matrix system of methyl cellulose (MC)/sodium alginate (SA)/MC or MC/carboxymethyl chitosan (CMC)/SA wall formulation is more suitable for CAL microencapsulation. Moreover, a novel quantitative method is also proposed to verify the most stable wall material microencapsulation. The quantitative results show that the highest activation energy (53.00 ± 2.24 kJ/mol) is observed for the MC/CMC/SA-encapsulated CAL microcapsule. Taken together, the results suggest that MC/CMC/SA wall formulation shows excellent barrier properties and is superior to other wall materials in preventing microencapsulated CAL deterioration. This study will be efficient in designing an ideal capsule for CAL microencapsulation.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 138
·期 4
·49730
·
IF 2.52
Kunxiang Shi,Yucai Shen,Yunxu Yang,Tingwei Wang
A series of latent curing agents were developed by replacing the hydrogen atom on secondary amine in imidazole with methoxy polyethylene glycol maleate diesters via Michael addition reaction. Methoxy polyethylene glycol maleate diesters with different molecular weight also restrained the reactivity of tertiary amine in imidazole ring. The curing properties and pot-life of the modified imidazole/epoxy systems were measured by differential scanning calorimeter and rotational rheometer. The modified imidazole/epoxy system could be cured quickly at 175°C. The modified imidazole shows good latency. After stored for more than 1 month, viscosity of modified imidazole/epoxy system remains unchanged. The longer chain polyether had the better thermal latency these curing agents had. Compared with unmodified imidazole, the novel latent curing agents led to better impact strength for cured epoxy. However, the compatibility between epoxy and latent curing agent will get worse if the molecular weight of polyether unite is over 750.
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 138
·期 2
·49678
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IF 2.52
Jiabao Guo,Haijie Li,Bingfeng Xue,Donghui Zhu,Xiaomeng Zhang,Haitao Zhao,Xiaoguang Qiao,Zhe Cui,Peng Fu,Qingxiang Zhao,Xinchang Pang,Minying Liu
To fabricate the low-cost transparent polyamide with high heat resistance and good melt flowing property simultaneously is a huge challenge in many high-end fields due to the contradiction between these two properties. In order to balance this contradiction, in this paper, by using isophthalic acid (IPA, aromatic monomer), 4,4′-methylenebis(cyclohexylamine) (PACM, alicyclic monomer) as rigid stereoscopic monomers, 1,6-hexanediamine (HMD, aliphatic monomer) as the flexible monomer, a series of transparent poly(hexamethylene isophthalamide/poly(m-benzoyl4,4′-methylenebis(cyclohexylamine)) (PA6I/PACMI) with rigid and stereoscopic structure (corresponding to the large distance between adjacent molecular chains) were successfully synthesized. The results indicated that the newly synthesized PA6I/PACMI copolymer has an intrinsically amorphous structure and high optical transparency, which could reach as high as 90%. Furthermore, the highest glass transition temperature ( T g ) of the copolymer is over 153.9°C, at the same time, the copolymer also possesses excellent melt flowing property, which can be melt processed easily. Therefore, the newly synthesized copolymer has great advantages in many fields, and it can also shed light on the design and fabrication of high-performance materials.
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 138
·期 1
·49622
·
IF 2.52
Feifei Lu,Peiyu Tan,Yuge Han
Polyaniline (PANI) films and its electrochromic devices based on various porous substrates were obtained by electrochemical deposition. The pore size distribution of the porous substrate has shown important influence on the infrared emissivity variation (∆ ε ) of the device. Morphology and structure of PANI were characterized by scan electronic microscopy (SEM) images and Fourier transform infrared spectra (FTIR). SEM images present the morphology difference of PANI on different substrates, which suggest that large pores will prevent PANI particles from forming orderly and compactly films. FTIR spectrum indicates that pore size of substrates affects the orientation of PANI chains. Furthermore, electrochemical properties and stability of PANI films were analyzed by cyclic voltammetry (CV) curves. And the CV curve revealed that the generation of irreversible degradation products is the reason for poor stability of PANI films. Finally, greatly improved ∆ ε of 0.559 in 3–5 μm waveband and 0.39 in 8–14 μm waveband is achieved by choosing a small pore substrate.
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 137
·期 38
·49148
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IF 2.52
Wei Gao,Yuan Yu,Tingting Chen,Qingwu Zhang,Zhongwei Chen,Zhiquan Chen,Juncheng Jiang
Three metal oxides (MOs) (Fe 2 O 3 , Sb 2 O 3 , Al 2 O 3 ) were incorporated into blends of unsaturated polyester resin (UPR)/ammonium polyphosphate (APP) composites with the aim of studying and comparing their synergistic effect on flame retardancy with APP. The UPR-APP/MOs composites were prepared, then the thermal stability and flame-retardant properties of the UPR composites were evaluated by thermogravimetric analysis (TGA), limiting oxygen index (LOI), vertical burning test (UL-94), and cone calorimetry test (CCT). Besides, residues after CCT were characterized by scanning electron microscopy and laser Raman spectroscopy. The LOI values of the UPR composites with 0.5 wt% MOs increased to around 40%. However, the CCT results indicated that the incorporation of Sb 2 O 3 brought an increase in the total heat release. Moreover, these three MOs had different effects on the process of thermal degradation of UPR composites from the TGA results. Based on the above results, Al 2 O 3 provided a best promotion on flame retardancy among three MOs.
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 137
·期 39
·49167
·
IF 2.52
Jiaqi Shang,Song Mei,Danyu Zhao,Jianping Deng
Optically active hybrid particles consisting of chiral organic component and inorganic component integrate the individual advantages of the components in one entity. This article reports a new type of optically active hybrid particles constructed by helical substituted polyacetylene and octavinyl polyhedral oligomeric silsesquioxane (OvPOSS). The hybrid particles were prepared in a two-step process. First, helical substituted polyacetylene with pendent vinyl groups was synthesized and named as macromonomer (MM). Then, hybrid particles were prepared from MM and OvPOSS by free radical suspension polymerization, in which OvPOSS acted simultaneously as comonomer and crosslinking agent. OvPOSS and MM together constituted a crosslinked network and formed spherical, porous hybrid particles. The resulting hybrid particles exhibited the desired optical activity, according to circular dichroism spectroscopy measurement. As an organic/inorganic hybrid molecule itself, OvPOSS moderately improved the thermostability of the organic component and meanwhile increased the porosity of the hybrid particles. It also helped to tune the surface morphology of the hybrid particles. The present study provides a novel class of optically active hybrid particles, and the preparation strategy may further work as a versatile platform for developing novel chiral hybrid materials.
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 137
·期 38
·49143
·
IF 2.52
Qian Zhang,Guokang Chen,Kun Wu,Jun Shi,Liyan Liang,Mangeng Lu
A biphenyl type liquid crystal epoxy (LCE) monomer 4,4′-di(2,3-epoxyhexyloxy)biphenyl (LCBP4) containing flexible chain was synthesized and the curing behavior was investigated using 4,4′-diaminodiphenylmethane (DDM) as the curing agent. The effect of curing condition on the formation of the liquid crystalline phase was examined. The cured samples show good mechanical properties and thermal stabilities. Moreover, the relationship between thermal conductivity and structure of liquid crystalline domain was also discussed. The samples show high thermal conductivity up to 0.28–0.31 W/(m*K), which is 1.5 times as high as that of conventional epoxy systems. In addition, thermal conductive filler, Al 2 O 3 , was introduced into LCBP4/DDM to obtain higher thermal conductive composites. When the content of Al 2 O 3 was 80 wt%, the thermal conductivity of the composite reached to 1.86 W/(m*K), while that of diglycidyl ether of bisphenol A (Bis-A) epoxy resin/DDM/Al 2 O 3 was 1.15 W/(m*K). Compared with Bis-A epoxy resin, the formation of liquid crystal domains in the cured LCE resin enhanced the thermal conductivity synergistically with the presence of Al 2 O 3 . Furthermore, the introduction of Al 2 O 3 also slightly increased the thermal stabilities of the cured LCE.
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 137
·期 36
·49066
·
IF 2.52
Yigane Wang,Xiaoan Nie,Guigan Fang,Laihui Xiao
Epoxy bisphenol acid isooctyl ester (EBAIE) was synthesized and characterized by FTIR and H-NMR. EBAIE was used as poly(vinyl chloride) (PVC) plasticizer for the first time, and its addition amount was 30 wt% of PVC. The mechanical properties, thermal stability, compatibility, and decomposition activation energy of PVC blends were systematically studied. Compared to the commercial plasticizer-dioctyl phthalate (DOP), the tensile strength had been significantly increased from 30.64 to 45.07 MPa, while the elongation at break had little difference. The thermal stability analysis showed that the static stability time at 180°C had been extended from 40 to 300 min. The decomposition activation energy indicated that the EBAIE plasticized PVC was with a higher thermal stability. The extraction and volatility resistance of the novel plasticizer were superior to those of DOP.
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 137
·期 38
·49127
·
IF 2.52
Yue Tang,Han-Qing Wang,De-Fa Hou,Huang Tan,Ming-Bo Yang
This article focuses on controlling the morphology of regenerated cellulose aerogel (RCA) and its application as a template for the preparation of functional cellulose nanoparticles (FCNPs). RCA is prepared by lyophilizing cellulose hydrogel which is fabricated through a sol–gel method in sodium hydroxide (NaOH)/urea aqueous solution. The morphology of RCA is adjusted by varying the gelation temperature and time. With the gelation temperature and time increasing, lamellar RCA transforms into strings of cellulose nanoparticles. Subsequently, RCA with the morphology of "strings of nanoparticles" is modified through the bulk condensation of l -lactic acid and RCA. Eventually, the prepared functionalized RCA (FRCA) is dispersed in an organic solvent to obtain purified FCNPs. The results demonstrate that single FCNP can be obtained by dispersing FRCA in dimethyl sulfoxide. Moreover, the prepared FCNPs have uniform size, good thermal-stability, and increasing hydrophobicity, which are ideal candidates for polymer composites in terms of fillers.
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 137
·期 35
·49016
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IF 2.52
Guancheng Jiang,Kai Wang,Yinbo He,Lili Yang,Xinliang Li,Yu Deng
To meet the increasing requirement of stabilizing shale under high-temperature situation with the use of water-based drilling fluids (WBDFs), the high-performance shale stabilizer is an urgent need. In this study, an amphoteric copolymer of AM/DMDAAC/NVP (APC) was synthesized by acrylamide (AM), dimethyl diallyl ammonium chloride (DMDAAC), and N -vinylpyrrolidone (NVP) and used as a high temperature-resistant shale stabilizer. The Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy confirmed the successful synthesis of APC. The inhibitive performance of APC was systematically evaluated and compared with three other commonly used shale stabilizers, including the anionic potassium polyacrylamide (KPAM), cationic poly dimethyl diallyl ammonium chloride (PD), and amphoteric polymer FA367. The results demonstrated that APC displayed excellent performance on the linear swelling test, hot-rolling recovery experiment, and shale immersion test. Furthermore, APC combined the advantages of high shale recovery percentages of PD and maintaining shale pellet integrity of KPAM, avoiding the drawbacks of enormous filtration volume of PD and low shale recovery percentages of KPAM. These great properties indicated that APC would be suitable as a shale stabilizer in WBDF to drill high-temperature shale formation.
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高影响因子
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