聚丙烯高速纺丝的研究

研究了分子量、分子量分布及纺丝工艺条件对聚丙烯高速纺得卷绕丝的结构及力学性质的影响。结果表明:改变聚丙烯树脂和调节纺丝工艺条件(如绕丝速度、纺丝温度和泵供量等)可以获得各种织构的聚丙烯纤维。适当选择上述参数以控制或改变卷绕丝的织构可提高高速纺出聚丙烯纤维的质量。     

分子量分布对等规聚丙烯卷绕丝织构形成的影响

本文研究了分子量分布对聚丙烯卷绕丝结构和性能的影响。结果表明,聚丙烯树脂中的高分子量尾端对卷绕丝的结构有明显影响。在通常的纺丝条件下,用控制降解的聚丙烯树脂纺得的卷绕丝具有低取向的次晶结构;而在相同的粘均分子量和纺丝条件下,高分子量尾端的存在使聚丙烯易于在纺丝线上生成结晶性较高的α-晶型,卷绕丝的取向也随高分子量尾端而显著增大。高分子量尾端对卷绕丝结构的影响,导致卷绕丝牵伸性能和成品纤维力学性能变差。     

聚丙烯纺丝成型与结构性能的关系第一报降低纺丝温度的研究

由于聚丙烯纺织温度太高,使防老助剂的分解、流失以及由此造成污染环境等缺陷。本文通过分析熔融纺丝过程中,造成熔体挤出膨化的原因,认为采用在喷丝板下方增添加热套筒,可减少或消除熔体挤出膨化,从而达到降低纺丝温度30～40℃的目的,也可提高纤维的均匀性并有刊十提高纺丝速度。与此同时也进行了加与不加热套筒和不同热套筒温度对初生纤维晶态结构、密度和双折射的影响;不同分子量的聚丙烯对纺丝温度的影响,以及与此有关的成型与纤维结构性能的关系的研究。     

海藻酸钠-羧甲基纤维素钠共混纤维的制备及其吸湿性能

以海藻酸钠(ALG)和羧甲基纤维素钠(CMC)两种天然高分子材料为纺丝原料,氯化钙水溶液为凝固浴,制得了吸湿性能优异、力学性能良好的海藻酸钠-羧甲基纤维素钠共混纤维。采用离心脱水法,系统研究了纺丝工艺条件、吸收环境对共混纤维吸湿性的影响,并在此基础上获得了海藻酸钠-羧甲基纤维素钠共混纤维的吸湿动力学模型。     

二氧化碳-环氧丙烷共聚物电纺纤维形貌研究

利用电纺丝技术制备了二氧化碳环氧丙烷共聚物超细纤维,研究了喷丝口电势、纺丝距离、浓度、溶剂等因素对纤维形貌、直径及均一性的影响.实验结果表明,利用电纺丝法可以制备直径在小于200nm到7μm二氧化碳环氧丙烷共聚物纤维;喷丝口电势和浓度对于共聚物电纺丝纤维是否形成串珠结构有重要影响;电势、距离和纺丝液浓度都对纤维直径及分散系数有较大影响,在一定范围内,随着喷丝口电势增加,纤维平均直径变大而分散系数变小;纺丝距离增大使得纤维平均直径变小,分散系数变大;浓度的增大使得纤维平均直径变大,分散系数变小;不同溶剂配制的溶液体系制备的电纺丝纤维形貌有很大差异,在二氯甲烷和丁酮的体系中,分别观察到了两组较为集中的直径分布.     

核-壳结构壳聚糖/聚乙烯醇-聚碳酸亚丙酯超细纤维的制备

利用同轴电纺丝技术制备出具有核-壳结构的壳聚糖/聚乙烯醇-聚碳酸亚丙酯电纺丝纤维,考察了溶剂复配对成纤的影响,采用扫描电镜和透射电镜对纤维的形貌、结构、直径分布等进行了探索,并在优化的工艺条件下,将羟基磷灰石负载在内层结构中.研究表明,采用氯仿/N,N-二甲基甲酰胺(1/1)复配溶剂可有效避免聚合物溶液在喷丝口处的凝结现象.同单纺纤维相比,核壳结构的纤维直径分布较宽,纤维壳层和核层界限清晰;红外谱图分析证明羟基磷灰石可负载在纤维的核结构中.     

聚丙烯-麦饭石功能纤维的性能

应用冷场发射扫描电镜(FE-SEM)、声速法、蠕变测试、苯胺吸附和振荡烧瓶法对聚丙烯-麦饭石功能纤维的形貌、取向因子、蠕变性、吸附性和抗茵率进行了测试与表征.研究表明:聚丙烯纤维和麦饭石添加剂呈镶嵌结构,聚丙烯-麦饭石功能纤维表面存在一些微细褶皱,其杨氏模量和取向因子相对较低,蠕变现象明显;苯胺的吸附率在30%左右;抗菌率在90%以上,而且水洗50次后抗茵率基本不变,具有很好的吸附和抑菌作用.     

β-环糊精功能化聚丙烯腈纳米纤维的制备及对亚甲基蓝的吸附性能

以N,N-二甲基甲酰胺(DMF)为溶剂,利用静电纺丝法制备了聚丙烯腈(PAN)/β-环糊精(β-CD)纳米纤维.通过场发射扫描电镜、红外光谱和粉末XRD对纳米纤维进行了表征,并检测了纺丝溶液的电导率和黏度.结果表明,β-CD的添加量可以改善纳米纤维的形貌,固定在纤维上的β-CD保留了空腔结构,为其在纳米纤维中发挥超分子...     

聚(3-羟基丁酸酯-co-3-羟基戊酸酯)改性及纤维成形北大核心CSCD

聚(3-羟基丁酸酯-co-3-羟基戊酸酯)(PHBV)是一种微生物发酵生产的热塑性聚合物。从物理、化学改性及其纤维成形两个方面综述了PHBV的研究进展。PHBV的物理改性主要有无机纳米粒子共混体系(PHBV/iNPs)、有机纳米晶共混体系(PHBV/oNPs)、高聚物共混体系(PHBV/Polymer)和绿色全降解共混体系;化学结构构筑主要包括接枝共聚改性、嵌段共聚改性、端基扩链改性等。从改性的手段及介质,分析了改性方法的优缺点。PHBV纤维的成形方法主要有熔融纺丝法、干法纺丝法及静电纺丝法。从PHBV纤维应用领域看,熔融纺纤维应用目标在于替代现有石油基相关产品,而静电纺纤维主要应用于开拓组织工程再生医学领域。最后,对PHBV今后的研究及发展提出了展望。     

过冷等规聚丙烯熔体的流变学行为

采用毛细管流变仪研究低于表观熔点的过冷聚丙烯熔体的流变学行为.过冷聚丙烯熔体先经过一段诱导期后,熔体发生凝胶化,剪切黏度在短时间内大幅度升高,最终固化结晶.在诱导期中,过冷聚丙烯熔体的流变行为与高于聚丙烯熔点的常规熔体的流变行为相仿.诱导期的长度与温度有关.在160℃下,诱导期的长度足够长,于是使用过冷聚丙烯熔体进行纺丝加工成为可能.实验结果表明,由过冷熔体制备的初生纤维各项性能与由高温熔体制备的初生纤维亦相似,因此,通过降低喷丝头温度的方法发展一种节能降耗的聚丙烯纤维制造技术有潜在的可能性.     

DISPERSITY OF THE COPOLYMER OF STYRENE AND 2, 2, 6, 6-TETRAMETHYL-4-PIPERIDINYL-METHACRYLATE (PDS) IN POLYPROPYLENE AND ITS INFLUENCE ON PHOTOSTABILIZING ACTION OF PDS

The morphology of films of PDS/PP blends with various contents of PDS and with PDS of dif-ferent molecular weights was examined by scanning electron microscopy and the photostability ofthese films was studied by infrared spectrometry. Experimental results show that PDS is dispersedin PP matris as spherical globules being in size of the order of 10~(-1)μm when content of PDS is in therange of 0.1 % to 1%. The phase separation of PDS from PP results in decrease in photostabilizingaction of PDS to some extent. It is found that films of PP blended with PDS of different molecularweights show similar morphology and photostabilizing action if the content of PDS is kept constant.     

ENHANCEMENT OF COMPATIBILITY OF POLYPROPYLENE AND NYLON-66 BY MALEATED POLYPROPYLENE

The compatibility of PP/N-66 blending system modified with maleated polypropylene was studied by means of SEM, DMA and other mechanical testing. It was found that when proper amount of modifier was applied, the compatibility was greatly enhanced and the impact toughness was significantly improved. An important direct evidence of the formation of the interfacial copolymer was also found. However, when excessive amount of modifier was used, the modification effect was not conspicuous. The phenomena were interpreted from a view of molecular motion that the interfacial block copolymer forced the two components to 'compatibilize' and many flexible PP molecules were set free from the restraint of the crystallites of plain PP so as to absorb much more impact energy.     

尼龙6/多单体接枝聚丙烯共混物的形态结构及力学性能的研究

用多组分熔融接枝的方法将甲基丙烯酸缩水甘油酯（ Ｇ Ｍ Ａ） 和苯乙烯（ Ｓｔ） 共同接枝于聚丙烯（ Ｐ Ｐ） 上,制得多单体接枝聚丙烯 Ｐ Ｐ ｇ （ Ｇ Ｍ Ａ ｃｏ Ｓｔ） ．该接枝物具有高的 Ｇ Ｍ Ａ 接枝率．本研究利用 Ｆ Ｔ Ｉ Ｒ、 Ｓ Ｅ Ｍ、 Ｔ Ｅ Ｍ、 Ｄ Ｓ Ｃ 和力学性能测试等分析方法,研究了多组分熔融接枝聚丙烯（ Ｐ Ｐ ｇ （ Ｇ Ｍ Ａ ｃｏ Ｓｔ）） 对尼龙６／ Ｐ Ｐ 共混物的形态结构, Ｔｇ 和力学性能的影响．结果表明, Ｐ Ｐ ｇ （ Ｇ Ｍ Ａ ｃｏ Ｓｔ） 中的环氧基团与尼龙６（ Ｐ Ａ６） 末端的胺基发生化学反应,原位形成的 Ｐ Ｐ Ｐ Ａ６ 共聚物能有效的改善 Ｐ Ａ６ 与 Ｐ Ｐ 的相容性,可以使 Ｐ Ｐ 均匀的分散在 Ｐ Ａ６ 基体中,相区尺寸明显减小,提高了拉伸强度．由于两相的相容性较好,从而共混物的 Ｔｇ 有明显的变化．此外,通过透射电镜观察,发现 Ｐ Ａ６／ Ｐ Ｐ ｇ （ Ｇ Ｍ Ａ ｃｏ Ｓｔ）（７０／３０） 合金中存在着特殊的微相分离结构．     

聚丙烯与马来酸酐在超临界CO2中的接枝聚合

聚丙烯(PP)以其强度高、耐热性好、密度小、易加工和价廉等特点成为重要的通用塑料。但由于非极性的分子结构,其亲水性、染色性、抗静电性、粘接性和印刷性并不理想,难以与极性聚合物和填料共混、复合。PP通过接枝引入极性基团是最常用的化学改性方法。常用的接枝单体有马来     

SALS AND MORPHOLOGY OF POLYPROPYLENE SPHERULITES

Spherulites of different morphological features have been obtained by varying the cooling rateof polypropylene melts through the crystallization temperature range from 120℃to 90℃. It wasfound that SALS is very sensitive to the changes of internal structure of the spherulites, and information about their morphological difference can be obtained according to the model theories and statisticaltheories of SALS.     

聚丙烯表面光接枝及染色

用UV光照法将两种亲水性单体(甲基丙烯酸和丙烯酰胺)分别接枝到非亲水性的聚丙烯板表面上。以二苯酮为光敏剂,丙酮为溶剂,在不断通入氮气的条件下,采用汽-固相接枝法,可以一次完成双面接枝。电子能谱(ESCA)的结果证实了光接枝的成功。水接触角测试结果表明,接枝后的聚丙烯表面具有良好的亲水性。利用水溶性的染料(结晶紫和罗丹明B)对接枝后的聚丙烯板进行了染色,并测定了吸收光谱和荧光光谱。     

添加型聚丙烯大分子表面改性剂PP-g-PEG的制备及其应用

以马来酸酐为桥联剂,通过其与单端羟基聚乙二醇的反应,合成了大分子表面改性剂聚丙烯-聚乙二醇接枝共聚物,探索了反应条件对接枝反应的影响,用IR、NMR、TGA、DSC对接枝物的结构及性能进行研究,并通过共混研究了接枝物对聚丙烯的表面改性效果.结果表明,提高马来酸酐接枝聚丙烯或聚乙二醇的分子量,会阻碍接枝反应的进行,接枝率明显下降;接枝聚乙二醇降低了接枝物的结晶能力;聚丙烯-聚乙二醇接枝共聚物的热稳定性随着聚乙二醇的含量增加及侧链聚乙二醇长度的增加略有下降;聚丙烯-聚乙二醇接枝共聚物组分在共混物中具有明显的向外择优迁移特性,可以作为聚丙烯的添加型表面改性剂使用.     

MORPHOLOGY AND MECHANICAL PROPERTIES OF POLYPROPYLENE WITH in situ FORMED POLYAMIDE-6 FIBRILS

in situ Fibril formation of polyamide-6(PA6)in isotropic polypropylene(iPP)was first fabricated using a slit die extrusion and hot stretching process.Then the prepared materials were subjected to injection molding in the temperature range higher than the melting temperature of iPP but lower than that of PA6.The obtained injection-molded samples were characterized via scanning electron microscopy(SEM),differential scanning calorimetry(DSC)and two-dimensional wide- angle X-ray scattering(2D-WAXS).Mechanical properties were also investigated.The SEM result shows that the optimum fibril formation could be only achieved in the range of 20 wt% to 30 wt% of PA6 content for the studied system.The fibril morphology changes along the sample thickness in the injection-molded bars.The fibril morphology in the skin layer was better than that in the core layer.2D-WAXS results showed that the orientation of PP decreased with the increase of PA6 content,which indicated that the orientation of PP was confined by PA6 fibrils.Combined consideration of mechanical properties and morphology indicates that only PP/PA6 composites with 20 wt% of PA6 content show better properties because of the better fibril morphology and PP chain orientation.     

多组份聚丙烯共混物的微观结构及共混纤维的染色性能

研究了PP GPET、PP GPET EVA、PP GPET EVA PS共混物的结构和性能 .研究表明 ,PP GPET体系属于非相容共混体系 ,共混物呈典型海岛型两相结构 ,EVA的加入可以改善体系相容性 ;共混物的结晶度比纯聚丙烯低 ,PS有增大共混物晶粒尺寸的作用 ;改性聚丙烯纤维的染色性有明显提高 ,用分散染料E EX可染成深蓝色     

CRYSTALLIZATION AND MECHANICAL PROPERTIES OF POLYPROPYLENE FILLED WITH SiO2 NANOPARTICLES

Oleic acid （OA）-modified SiO2 （OA-m-SiO2） nanoparticles were prepared using surface modification method. Infrared spectroscopy （IR） was used to investigate the structure of the OA-m-SiO2 nanoparticles, and the result showed that OA attached onto the surface of SiO2 nanoparticles through esterification. Effect of OA concentration on the dispersion stability of OA-m-SiO2 in heptane was also studied, and the result indicated that OA-m-SiO2 nanoparticles were dispersed in heptane more stably than the unmodified ones. OA-m-SiO2 nanoparticles can also be dispersed in polypropylene （PP） matrix in nano-scale. The effect of OA-m-SiO2 on crystallization of PP was studied by means of DSC. It was found that the introduction of OA-m-SiO2 resulted in significant increase in the crystallization temperature, crystallization degree and crystallization rate of PP, and OA-m-SiO2 could effectively induce the formation of β-crystal PP. Effect of OA-m-SiO2 content on mechanical properties of PP/OA-m-SiO2 nanocomposites was also studied. The results show that OA-m-SiO2 can significantly improve the mechanical properties of PP.