【正文】 是：沖擊強(qiáng)度高，即使在 20~30 ℃下也不呈現(xiàn)脆性破壞；剛性隨溫度變化無(wú)明顯下降，抗蠕變性、尺寸穩(wěn)定性、耐藥性優(yōu)良并且吸濕性低。 尼龍 66 是結(jié)晶性 聚合物，如不加阻燃劑，其阻燃性較差。目前對(duì)尼龍 66 阻燃改性的研究越來(lái)越受到人們的關(guān)注 [9]。常用增塑劑甲醇、乙醇、丙醇、磺酰胺等對(duì)尼龍 66 進(jìn)行增塑改性。為了進(jìn)一步提高其性能，通常對(duì)尼龍進(jìn)行潤(rùn)滑改性 [ 910 ]。 納米改性尼龍 采用無(wú)機(jī)填料填充改性可降低成本 但研究結(jié)果表明：在 PA66 中加入剛性粒子時(shí) ,通 常在提高材料剛性的同時(shí) ,降低了材料的韌性填充量越高 ,其作用越顯著 , 近年來(lái)聚合物基有機(jī) /無(wú)機(jī)納米復(fù)合材料作為材料科學(xué)的一支新秀，已引起人們的 廣泛關(guān)注這類材料具有有機(jī)和無(wú)機(jī)材料的特點(diǎn)，并通過(guò)兩者之間的耦合作用產(chǎn)生出許多優(yōu)異的性質(zhì)，有著廣闊的發(fā)展前景，是探索高性能復(fù)合材料的一條重要途徑。 【 13】 洛陽(yáng)理工學(xué)院畢業(yè)設(shè)計(jì)（論文） 12 研究展望 從以上綜述可以看出，國(guó)內(nèi)外在該聚酰胺改性技術(shù)領(lǐng)域的研究有了較大的發(fā) 展，但大都停留在試驗(yàn)階段，其中納米填充以及納米 和晶須復(fù)合填充的方法得到綜合性能優(yōu)異的合金材料具有較好的工業(yè)化前景，但合金制備和改性的加工工藝還有待進(jìn)一步研究。 在共混過(guò)程中熔體粘度增大，流動(dòng)性降低使加工難度加大在獲得高韌性材料的同時(shí)不損失流動(dòng)性的問(wèn)題還有待于解決。 【 14】 洛陽(yáng)理工學(xué)院畢業(yè)設(shè)計(jì)（論文） 13 第 4 章 PA66 應(yīng)用現(xiàn)狀與前景 PA66 應(yīng)用現(xiàn)狀 國(guó)外現(xiàn)狀 １９３５年美國(guó)杜邦公司的卡羅瑟斯等人在實(shí)驗(yàn)室中用己二酸和己二胺制成了尼龍６６，發(fā)現(xiàn)這是一種具有重大意義的工業(yè)原料。在第二次世界大戰(zhàn)中，這些材料在軍事方面的應(yīng)用也得到了很大發(fā)展。 國(guó)內(nèi)狀況 我國(guó)尼龍６６的發(fā)展是從７０年代后期才開(kāi)始的，先是遼陽(yáng)石油化纖公司從法國(guó)羅地亞引進(jìn)了己二腈、 己二胺、６６鹽以及聚合等技術(shù)，開(kāi)始了中國(guó)式的尼龍６６產(chǎn)業(yè)化生產(chǎn)。目前已擁有尼龍６６鹽２０萬(wàn)噸，尼龍６６樹(shù)脂１２ .５萬(wàn)噸，工業(yè)絲和簾子布１０萬(wàn)噸的 生產(chǎn)能力，在規(guī)模上位居亞洲第一、世界第五的水平?！?15】 市場(chǎng)預(yù)測(cè) 為了提高 PA 同其它材料 (包括工程塑料 )的競(jìng)爭(zhēng)力擴(kuò)大應(yīng)用范圍 ,提高市場(chǎng)占有份額 ,通常從提高制品性能、降低成本和有利于環(huán)境這三個(gè)方面改進(jìn)產(chǎn)品品級(jí)和性能 ,如 DuPoni、 D S M、 Rhodia、東麗公司等 PA 樹(shù)脂生產(chǎn)廠家都先后推出了快速成型品級(jí) ,縮短了成型周 期 ,降低了生產(chǎn)成本 。 工業(yè)家和咨詢家普遍對(duì)以工程塑料的未來(lái)市場(chǎng)持樂(lè)觀態(tài)度 ,有的認(rèn)為 2020 一2020 年其用量將以年均 7% 的速率遞增 ,也有報(bào)道預(yù)計(jì) 2020 一 20 06 年間世界PA 工程 塑料市場(chǎng)的年均增長(zhǎng)率為 5%一 6 %。目前歐洲汽車廠應(yīng)用 PA 吸氣歧管走在前列 ,預(yù)計(jì)美國(guó)和其它地區(qū)會(huì)很快跟上。目前已見(jiàn)報(bào)的樹(shù)脂品種已超過(guò)萬(wàn)余種，而且已實(shí)現(xiàn)工業(yè)化生產(chǎn)并投入實(shí)際應(yīng)用的樹(shù)脂最少也有 300 余種。再次感謝幫助過(guò)我的老師和師父?jìng)儭?Paul Sabatier, 31062 Toulouse cedex 09, France ARTICLE I NFO Article history: Received 13 November 20 09 Received in revised form 7 July 2020 Accepted 25 July 2020 Available online 30 July 2020 Keywords: Dielectric Relaxations Piezoelectric abstract ABSTRACT Therm o Stim ulated Current (TSC) bined with Dyn amic Diel ectric Spec troscopy (DDS) have been applied to the investigation of dielectric relaxation modes of an evenodd Polyamide PA 6,9. The correlation between results obta ined by both meth ods allows us to describe precisely the molecu larmobility. At high temperature, the various dielectric relaxation phen omena are separated by applying t he dielectric modulus formalism. The parison between the activation enth alpy values obtained by DDS and TSC leads to the assignment of the socalled a mode to 20 cooperative movements of polymeric sequences. Molecular mobility of PA 6,9 is pared with the one of PA 11. The piezoelectri cactivity of PA 6,9 is shown and analyzed. 2020 Elsev ier Ltd. All rights reserved. 1. Introduction Piezoelectric polymers have been the subject of a lot of work sincethe discovery of the piezoelectric behaviour of poly(vinylidene fluo ride) PVDF by Kawai in 1969 [1].The understanding of the molecularorigin of the ferroelectricity of PVDF [24] initiates the developmentof its vinylidene fluoride etrifluoroethylene copolymers[5,6](P(VDFTrFE )) and v inyl id en e fluoride etrifluoroethylene echloro fluoroethylene terpolymers [7, 8] (P(VDFTrFECFE)).Scheinbeim etal. [9].discovered the ferroelectric behaviour of odd numbered polyamidesand showed that the remanent polarization is linearly dependentupon the dipolar density of amide groups. More recently, a new class of evene odd polyamide PA 6,9 has been elaborated. Franco that the room temperature crystalline structure of PA 6,9 differs from the classic hydrogen bonded sheet structure of PA 6, a structural point of view, PA 6,9 might have analogies with oddeven polyamides but the corresponding studies are mostly concentrated on the crystalline structures and mechanical properties[11] . As far as we know, the dielectric and the ferroelectric behaviourof evene odd polyamides have not yet b een shown. In this work,molecular mobility of dipolar entities of polyamide 6,9 has been characterized using a bination of thermo stimulated current (TSC) and dynamic dielectric spectroscopy (DDS). For the first time,polarization and piezo/pyroelectric coef ficients have been measured showing the ferroelectric behaviour of polyamide 6, 9. 2. Experimental section . Dielectric analyses The polyamide 6,9 films were elaborated by melting the polymer powder at 240℃ in a hot press. The cristallinity rationc χ℃ of PA6,9 obtained by DSC was measured near 16%. DDS was performed on unstretchedfi lms of about 100μm. In 21 this case, a humidity content of 1% has been determined by thermogravimetry analyses[12] . A Novocontrol Broadband Dielectric Spectrometer system BDS400 was used to measure the dielectric permittivity on extended temperature and frequency scales. Isothermal measurements were carried out in the frequency range of 101to 106 Hz for temperature varying from 150 to 150℃ by steps of 5℃ . The plex dielectric permittivity ε*extracted from dynamic dielectric spectroscopy(DDS) was recorded as a function of angular frequency u and fitted by the HavriliakeNegami function [13] : (1) where εs is the static permittivity, ?? is the permittivity at high frequency, and β HN,γHN are the Havriliak Negami parameters. But for symmetric mode (Cole Cole) as b relaxation for example, the γHN parameter is equal to 1. The dielectric loss modulus M39。39。39。2) (2) In the modulus formalism, Maxwelle Wagnere Sillars (MWS) polarization which usually occurs in heterogeneous systems like semicrystalline polymers [14, 15]is observed as a mode. In the ε39。are presented in Fig. 1. This formalism allows a better resolution of high temperature modes that could be partially hidden by the MWS contribution. Six relaxation modes are pointed out on the 3D dielectric relaxation map. The low temperature g mode is attributed to the molecular mobility of aliphatic sequences of PA 6,9. It is now generally accepted in polyamides that the g relaxation involves a mobility of the methylene groups between amide linkages [16] . The β 2and β 1submodes are related to the