功能化纳米纤维素复合PLA/PBAT薄膜的制备及性能

以γ-氨丙基三乙氧基硅烷(KH550)为改性剂对纤维素纳米纤维(CNF)进行功能化改性，并用聚丙二醇(PPG)对改性后的CNF进行包覆，制备了CNF-PPG纳米粒子。将其作为填料加到聚乳酸(PLA)/聚己二酸/对苯二甲酸丁二醇酯(PBAT)聚合物基体中，用溶液浇铸法制备了PLA/PBAT/CNF-PPG复合薄膜。通过FTIR、XPS、SEM、DSC、TG对薄膜进行了表征，探讨了PLA与PBAT的质量比及CNF-PPG纳米粒子的添加量对复合薄膜机械强度、热稳定性、阻隔性能的影响。结果表明，PLA/PBAT薄膜比纯PLA薄膜具有更高的韧性和热稳定性；当m(PLA)∶m(PBAT)=90∶10、CNF-PPG纳米粒子用量(以PLA和PBAT的质量为基准，下同)为10%时，PLA/PBAT/CNF-PPG(90/10/10)复合薄膜的拉伸强度达到(33.38±0.64) MPa，断裂伸长率为39.97%±0.67%；复合薄膜最终降解温度从纯PLA膜的394℃提高到435℃；复合薄膜的水蒸气和氧气透过系数分别为4.98×10^–14 g·cm/(cm²·...     

抗菌母料中Nano-ZnO/CCA配比对PLA/AMB/TBC纳米复合材料性能的影响

以聚乳酸(PLA)为基体树脂,nano-ZnO和叶绿素酮酸(CCA)为复合抗菌剂,通过溶液共混制得抗菌母料(AMB),用PLA与AMB、柠檬酸三丁酯(TBC)热机械共混制得PLA/AMB/TBC纳米复合材料。研究了母料中nano-ZnO/CCA质量配比对纳米复合材料抗菌性能和力学性能的影响。结果表明,少量CCA的加入使纳米复合材料对大肠杆菌的抗菌性能大幅度提高;当纳米复合材料中TBC和nano-ZnO质量分数分别为10%和0.9%,AMB中nano-ZnO/CCA质量配比为18/8时,纳米复合材料的抗菌性能最好,其抗菌率达到99.6%,断裂伸长率是纯PLA的2.17倍,拉伸强度、弯曲强度和冲击强度保留率分别为75%,65%,70%。     

非共价功能化石墨烯改性PLA薄膜的制备

以双十二烷基二甲基溴化胺非共价修饰还原石墨烯(DDAB–RGO)为纳米填料,通过溶液铸膜法制备了聚乳酸/功能化石墨烯(PLA/DDAB–RGO)纳米薄膜。用傅立叶变换红外光谱和扫描电子显微镜对DDAB–RGO及纳米复合薄膜的化学结构及形貌进行了表征,并对纳米薄膜的结晶性能、力学性能、热稳定性等进行了测试分析。结果表明,DDAB–RGO与PLA具有良好的相容性,均匀分散于PLA基体中,在较低DDAB–RGO含量时对PLA膜起到了纳米增强的作用,当其含量为0.2%时,PLA/DDAB–RGO纳米薄膜的拉伸强度、拉伸弹性模量比纯PLA膜分别提高了21%和36%。同时DDAB–RGO的加入还改善了PLA的结晶性、热稳定性。     

PP/PLA/CaCO_3复合材料的制备与性能研究

以聚丙烯(PP)为基体,聚乳酸(PLA)和纳米碳酸钙(CaCO_3)为增韧、增强组分,利用熔融共混制得PP/PLA/CaCO_3复合材料,通过对复合材料力学性能、耐热性能、流变性能与结晶形态的表征,研究了PLA和纳米CaCO_3对复合材料性能的影响及其机理。结果表明,当PP与PLA共混时,形成连续空间网络结构PLA有助于改善PP的性能,PLA质量分数为20%时综合力学性能最佳,与纯PP相比,PP/PLA复合材料的拉伸强度和缺口冲击强度分别提高5. 14%和54. 35%,断裂伸长率降低62. 47%。向PP基体中引入的纳米CaCO_3通过"滚珠增韧"和"异相成核"作用明显改善复合材料力学性能,纳米CaCO_3质量分数为15%时,在PP/PLA中均匀分散产生的晶粒细化作用效果最为显著,PP/PLA/CaCO_3复合材料的综合力学性能达到最佳,拉伸强度、断裂伸长率和缺口冲击强度分别比未添加CaCO_3时提高了15. 23%、2. 67%和5. 63%。     

PBAT/PLA/TPS生物降解薄膜的制备及性能研究

聚对苯二甲酸-己二酸-丁二醇酯(PBAT),聚乳酸(PLA)和热塑性淀粉(TPS)通过熔融共混并挤出吹膜。固定PBAT的质量分数为50%,改变PLA和TPS的比例。对PBAT/PLA/TPS薄膜的力学性能、热性能、结晶行为、撕裂断面形态、阻水性和氧气渗透性进行了研究。结果表明,PBAT/PLA/TPS薄膜中PLA的冷结晶温度降低了约40℃,PLA的冷结晶能力增强。随着TPS含量的增加,PBAT/PLA/TPS薄膜的拉伸强度降低、断裂伸长率增加。通过扫描电子显微镜观察,PBAT/PLA/TPS薄膜表现为明显的韧性断裂。水接触角和氧气渗透性测试表明薄膜具有良好的应用性能。     

静电纺PLA微/纳米纤维膜的浸润性能研究

采用静电纺丝技术制备聚乳酸(PLA)微/纳米纤维膜,研究了其可纺性、浸润性能及结构。结果表明:以二氯甲烷为溶剂的PLA电纺丝溶液,当PLA质量分数为7%时,可纺出纤维直径为280～690 nm的PLA微/纳米纤维膜。PLA微/纳米纤维膜与水的接触角为127.6°,高于PLA流延膜与水的接触角107.7°;红外光谱分析表明,PLA微/纳米纤维膜的分子组成没有发生变化;X光电子能谱测试表明PLA微/纳米纤维膜的表面碳氧含量比高于PLA流延膜,PLA微/纳米纤维膜的疏水性得到提高。     

近红外光响应聚乳酸薄膜的制备及其性能研究

采用了层层自主装沉积技术制备了具有近红外光响应的聚乳酸/硫酸软骨素/金(PLA/CS/Au)薄膜,并研究了纳米金在PLA/CS表面的分布情况及激光功率对PLA/CS/Au薄膜的影响。FTIR光谱证实了PLA/CS的成功合成。TG分析中,PLA/CS/Au薄膜中纳米金的含量大致在5%,验证了PLA/CS/Au薄膜的成功合成。TEM表明纳米金仅存在于PLA/CS薄膜表面,而且纳米金对PLA/CS薄膜具有稳定的附着性。近红外光响应测试表明,可以通过调节激光功率对PLA/CS/Au薄膜进行激光活化以释放或去除薄膜的上涂层,并且随着激光功率的升高,纳米金对薄膜的破坏程度也随之提高。     

PLA协同纳米CaCO3增韧PP的研究

通过熔融共混制得聚丙烯/聚乳酸/纳米碳酸钙（PP/PLA/CaCO3）复合材料,考察了PLA和纳米CaCO3对复合材料力学性能、热性能、流变性能与结晶形态的影响及其作用机理。结果表明,复合材料中形成连续空间网络结构的PLA有助于改善PP的性能,PLA含量为20 %（质量分数,下同）时复合材料综合力学性能最佳;与纯PP相比,加入PLA后的复合材料拉伸强度和冲击强度分别提高5.1 %和54.4 %,断裂伸长率降低62.5 %;纳米CaCO3通过“滚珠增韧”和“异相成核”作用明显改善复合材料力学性能,纳米CaCO3含量15 %时产生的晶粒细化作用效果最为显著,复合材料综合力学性能达到最佳,拉伸强度、断裂伸长率和冲击强度分别比未添加CaCO3时提升了15.2 %、2.7 %和5.6 %。     

PLA微纳米纤维复合过滤非织造布的制备与性能

通过液喷侧吹纺丝方法制备了聚乳酸(PLA)微纳米纤维和PLA/聚丙烯(PP)熔喷复合过滤非织造材料,探讨了液喷工艺参数对PLA微纳米纤维直径和分布的影响,并对不同制备条件下的PLA/PP复合过滤非织造布的力学性能、透气性及过滤性能进行了测试。结果表明,在PLA溶液质量分数为7%,风压为0.3 MPa,接收距离为35 cm,挤出速率分别为15,20,25 m L/h的条件下,可获得直径分别为0.98,1.02,1.12μm的PLA微纳米纤维。当液喷侧吹时间为30 min、挤出速率为20 m L/h时,PLA/PP复合过滤非织造布的透气性下降了52.48%,而过滤阻力、断裂强度和过滤效率分别提高了22.79%,94.51%和46.84%,其综合性能得到明显改善。     

聚乳酸/玻璃纸（PLA/CP）复合膜的制备及性能研究

以玻璃纸(Cellophane, CP)为基材,通过硅烷偶联剂KH550改性CP膜,将CP浸泡于聚乳酸(PLA)二氯甲烷溶液中制备PLA/CP复合膜,实现其力学性能及防水性能的改良。研究了KH550的质量分数、PLA的质量分数以及复合时间对PLA/CP复合膜的力学性能和防水性能的影响。研究表明,相比于未复合改性的CP膜,PLA/CP复合膜具有较强的力学性能及防水性能。当KH550的质量分数为0.2%时,PLA的质量分数为0.6%,复合时间为30min时,PLA/CP复合膜的力学性能最佳,杨氏模量与最大应力值分别为5 131.7 MPa和113.2 MPa;PLA的复合可以大幅度提高PLA/CP防水性能,水接触角最大可达87.8°,但其防水性能与PLA的质量分数以及时间无关。     

纳米氧化镁在丙二醇中的分散及稳定性研究*

通过吸光度和沉降实验研究了超声时间对纳米氧化镁在丙二醇中分散性能的影响,并用偶联剂对纳米氧化镁进行表面改性。结果表明：当分散剂聚乙二醇用量为1%（质量分数）、超声时间为10 min时,纳米氧化镁在丙二醇中的分散效果最佳。纳米氧化镁表面改性最佳工艺条件：铝酸酯偶联剂用量为8%（质量分数）,改性时间为2 h,球磨转速为900 r/min。改性后纳米氧化镁较未改性纳米氧化镁在丙二醇中的分散性及稳定性更好。     

Morphological and thermal properties of photodegradable biocomposite films

Biocomposites containing ultraviolet (UV) radiation absorbing inorganic nanofillers are of great interest in food packaging applications. The biodegradable polylactide (PLA) composite films were prepared by solvent casting method by incorporating 1 wt % of titanium dioxide (TiO₂) and Ag‐TiO₂ (silver nanoparticles decorated TiO₂) nanoparticles to impart the photodegradable properties. The films were exposed to UV radiation for different time periods and morphology of the composite films before and after UV exposure were investigated. The results showed that homogenous filler distribution was achieved in the case of Ag‐TiO₂ nanoparticles. The thermal properties and thermomechanical stability of the composite film containing Ag‐TiO₂ nanoparticles were found to be much higher than those of neat PLA and PLA/TiO₂ composite films. The scanning electron microscopy and X‐ray diffraction studies revealed that the photodegradability of PLA matrix was significantly improved in the presence of Ag‐TiO₂ nanoparticles. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

聚乳酸纳米颗粒的制备与表征

采用改良沉淀法制备了聚乳酸(PLA)纳米颗粒,采用响应面分析法建立数学模型对工艺条件进行优化. 结果表明,影响PLA颗粒制备的主要因素有PLA质量、油相中乙醇含量和油相体积,以平均粒径最小为目标,得到最优工艺条件为：聚乳酸质量76.82 mg,油相中乙醇含量40%(j),油相体积19.49 mL. 按最优工艺条件所制PLA颗粒的粒径为109.1 nm,多分散系数PDI值为0.084,与预测值偏差较小. PLA纳米颗粒为球形实心颗粒,分散性良好且粒径均一. PLA纳米颗粒能被巨噬细胞摄取,有望作为免疫佐剂.     

Gamma radiation induced property modification of poly(lactic acid)/hydroxyapatite bio‐nanocomposites

Poly(lactic acid)/hydroxyapatite (PLA/HAP) nanocomposite films with various compositions, 2 ? 70 parts HAP per 100 of the PLA polymer (pph), were made via the solution casting method. Transmission electron microscopy images of the PLA/HAP films exhibited spherical particles in the size range from nearly 10 nm to 100 nm dispersed within the polymeric matrix. Fourier transform infrared spectra of the nanocomposites revealed an interaction between PLA and HAP nanoparticles by carbonyl group peak shift. Incorporation of HAP nanoparticles in the PLA matrix stimulated crystal growth verified by differential scanning calorimetry. The films irradiated with γ‐rays at a dose of 30 kGy also showed an increase in crystallinity. The X‐ray diffraction patterns of the irradiated PLA exhibited two new peaks at around 16° and 19°, assigned to the α crystalline phase of PLA; these were absent in the unirradiated nanocomposites. Significant ductile behavior was observed in both irradiated and unirradiated PLA nanocomposites containing 2 and 10 pph of HAP. However, the irradiated nanocomposites had higher tensile strength. © 2013 Society of Chemical Industry     

不同分子量PCL增韧PLA的结构与性能

采用两种不同分子量的聚(ε-己内酯)(PCL)(粘均分子量60 000和3 000)与聚乳酸(PLA)在175℃下共混10 min制备PLA/PCL共混物。通过动态流变、扫描电子显微镜(SEM)和力学性能等研究了PLA/PCL共混物的结构和性能。动态流变显示,在PCL低含量(质量分数小于15%)时,PCL与PLA是相容的,质量分数为15%时PCL与PLA表现出明显的相分离行为。SEM显示,随着PCL含量的增加,PCL相的尺寸变大;低分子量PCL(L-PCL)的相尺寸明显大于高分子量PCL(H-PCL),而且相形态不是规则的球状。随着PCL含量的增加,共混物的拉伸强度下降,而断裂伸长率增加。当H-PCL质量分数为8.3%时,PLA/H-PCL共混物的断裂伸长率为137.32%。当H-PCL质量分数为15%时,其断裂伸长率高达232.76%。在添加相同含量PCL时,PLA/H-PCL共混物的拉伸强度高于PLA/L-PCL;而PCL质量分数8%时,共混物的断裂伸长率相差不多,当PCL质量分数大于8%时,PLA/H-PCL共混物的断裂伸长率明显比PLA/L-PCL共混物的高。     

PLA/metal oxide biocomposites for antimicrobial packaging application

ABSTRACT

The effects of metal oxide addition in polylactic acid (PLA) film were investigated in this study. PLA/Metal Oxide biocomposites were prepared by solvent casting method. The incorporation of metal oxide resulted in no chemical structure change of neat PLA. PLA/ZnO and PLA/MgO exhibited the widest inhibition while PLA/TiO₂ resulted in the smallest inhibition zone. The addition of metal oxides caused fracture and void on the surface of PLA. The addition of metal oxide into PLA films decreased the tensile strength at the concentration higher than 0.1 per hundred resin (phr). Incorporation of metal oxides accelerated the thermal degradation of PLA and tends to increase the biodegradability of PLA.     

Photoactivity of Poly(lactic acid) nanocomposites modulated by TiO2 nanofillers

Photoactivity of poly(lactic acid) (PLA) nanocomposites is of great interest for rational design of products for either short‐term/single‐use or long‐term/durable applications. We prepared PLA/TiO₂ nanocomposite films through a solution mixing/film casting method. Results showed that photodegradability/photostability of PLA could be well modulated by selecting appropriate TiO₂ nanofillers. TiO₂ nanoparticles and nanowires were characterized using X‐ray diffraction, UV–Vis–NIR spectrophotometer, and scanning electron microscopy. Changes in color, weight, structure, thermal stability, and phase transitions of PLA and nanocomposite films before and after UV irradiation were evaluated to study photoactivity characteristics. Pure PLA exhibited moderate photodegradability, but the photodegradability and photostability of PLA nanocomposites (PNA) were significantly enhanced by NanoActive (NA) TiO₂ nanoparticles and A type TiO₂ nanowires, respectively. Pure PLA had a weight loss of 27% after 38 days of UV irradiation. The weight loss of photodegradable (PD) PNA (PNA = PLA with 1% NA TiO₂) reached 38%, whereas that of photostable (PS) nanocomposites (P3AW) (P3AW = PLA with 3% A type TiO₂ nanowire) was only 5%. PD PLA exhibited characteristic peaks of carboxylic acid OH stretching and C?C double bond after UV irradiation in Fourier‐transform infrared spectra, whereas spectra of PS PLA remained almost the same. Thermal decomposition temperatures, glass transition temperatures, and melting temperatures of PD PLAs decreased dramatically after UV irradiation, but no obvious changes were observed for those of PS PLAs. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40241.     

添加纳米MgO和SiO2颗粒对二元碳酸盐(Li2CO3-K2CO3)比热容的影响

熔盐作为一种新型传热工质,由于其液体使用范围宽,比热容相对较高,蓄热能力强,已被广泛应用于聚热太阳能电站的储热传热介质,而通过增强熔盐的比热容可以显著提高其储热密度。将纳米SiO₂和MgO颗粒分别均匀分散到二元共晶碳酸盐（Li₂CO₃-K₂CO₃）中,制备出两种稳定的纳米流体,采用差式扫描量热法（DSC）分析纳米颗粒对熔盐比热容的影响。实验结果显示,添加20 nm的纳米颗粒对碳酸盐的比热容有显著影响：通过添加纳米MgO和SiO₂颗粒,纳米熔盐比热容相比基盐分别平均提高了27.5%～34.1%,11%～20.7%。经过多个固-液循环后,测得两种纳米流体的比热容变化率均低于4.31%,且具有良好的热稳定性。采用电子扫描显微镜表征纳米流体的微观结构,纳米流体在固态时的SEM图像显示在熔盐表面形成了特殊的纳米结构。     

水菱镁矿制备高分散六角片状纳米氢氧化镁的新工艺条件探究

以水菱镁矿为原料,通过“煅烧-水化-煅烧-水热”的简单合成路线制备了高分散六角片状的阻燃型纳米氢氧化镁。确定初步工艺后,探究了氧化镁用量、水热温度和水热时间对氢氧化镁结晶度和形貌的影响,确定最佳工艺水热条件：氧化镁用量为10%~25%（质量分数）、水热温度为150 ℃、水热时间为3 h。在水热过程中,分别向反应体系中加入聚乙烯吡咯烷酮（PVP）、十六烷基三甲基溴化铵（CTAB）、聚乙二醇6000（PEG6000）和聚乙二醇200（PEG200）,考察了不同改性剂及改性剂用量对氢氧化镁颗粒结晶度和分散性的影响。结果表明在4%（质量分数）PVP的条件下,能很好地改善纳米氢氧化镁的分散性,并得到了分散性好、晶形完整、粒径均匀、直径为300~400 nm、厚度为40~60 nm的六角片状纳米氢氧化镁。     

MgO/C-CoPcS催化剂的制备及其催化氧化脱硫醇性能

以碳酸镁、活性炭为原料，采用浸渍法制备了一系列MgO/C-CoPcS脱硫醇催化剂。研究了活性组分磺化酞菁钴（CoPcS）负载量和n(Mg)∶n(C)对催化剂活性的影响。通过XRD和BET对催化剂进行表征。实验结果表明， n(Mg)∶n(C)=0.2，CoPcS负载质量分数为1％时，催化剂活性最高。CoPcS的加入对催化剂的晶型没有影响；随着n(Mg)∶n(C)增加，MgO特征峰加强，比表面积降低。制备了n(Mg)∶n(C)=0.2，磺化酞菁钴负载质量分数为1％的MgO/C-CoPcS催化剂，进行了微型固定床反应实验。空速为2 h-1条件下，反应超过750 h，转化率保持在99％以上。