医用iPP混合二次料的多重结晶行为对制品脆裂的影响
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摘要
针对医用等规聚丙烯(i PP)二次料的添加对医用制品容易产生脆裂的问题,制备了混合不同比例的二次料的系列i PP样品,利用旋转流变测试、广角X射线衍射(XRD)以及万能力学试验等方法研究了混合不同比例二次料对i PP样品的流变特性、结晶行为以及力学性能的影响。结果表明,二次料的比例会明显影响体系的黏度和剪切应力变化;二次料的加入会改变聚合物结晶行为,导致样品内部存在α和γ多重结晶结构,γ晶产生影响制品性能,其含量与二次料比例存在正相关的关系;体系结晶度随二次料比例增加而上升,晶粒取向度变化规律则与之正好相反,所有这些在宏观上表现出拉伸强度随二次料比例增加稍有上升,弹性模量则随二次料增加呈下降趋势。
For the problem that the addition of medical isotactic polypropylene( i PP) secondary material could generate brittle cracking of medical products,a series of i PP samples mixed with different proportions of secondary materials were prepared. The effects of mixing different proportions of secondary materials on the rheological properties,crystallization behavior and mechanical properties of i PP samples were studied by rotational rheological test,wide-angle X-ray diffraction( XRD) and mechanical test. The results show that the ratio of secondary material could obviously affect the viscosity and shear stress of the system. The addition of secondary material could change the crystallization behavior of the polymer,lead to the formation of multiple crystal structures α and γ inside the sample. The γ crystal could affect the performance of the product. There is a positive correlation between the contents and the ratio of secondary materials. The crystallinity of the system increases with the increase of the proportion of secondary materials,and the law of grain orientation changes is exactly the opposite. All of them macroscopically show that the tensile strength increases slightly with the increase of secondary materials,and the elastic modulus decreases with the increase of secondary materials.
For the problem that the addition of medical isotactic polypropylene( i PP) secondary material could generate brittle cracking of medical products,a series of i PP samples mixed with different proportions of secondary materials were prepared. The effects of mixing different proportions of secondary materials on the rheological properties,crystallization behavior and mechanical properties of i PP samples were studied by rotational rheological test,wide-angle X-ray diffraction( XRD) and mechanical test. The results show that the ratio of secondary material could obviously affect the viscosity and shear stress of the system. The addition of secondary material could change the crystallization behavior of the polymer,lead to the formation of multiple crystal structures α and γ inside the sample. The γ crystal could affect the performance of the product. There is a positive correlation between the contents and the ratio of secondary materials. The crystallinity of the system increases with the increase of the proportion of secondary materials,and the law of grain orientation changes is exactly the opposite. All of them macroscopically show that the tensile strength increases slightly with the increase of secondary materials,and the elastic modulus decreases with the increase of secondary materials.
引文
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[2]唐毓婧,门永锋.剪切速率对等规聚丙烯的结晶和形貌的影响[J].高等学校化学学报,2016,37(2):367-372.
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[14] VARGA J,KARGER-KOCSIS J. Rules of supermolecular structure formation in sheared isotactic polypropylene melts[J]. J Polym Sci Part B Polym Phys,2015,34(4):657-670.
[15] XIAO W,WU P,FENG J. Effect ofβ-nucleating agents on crystallization and melting behavior of isotactic polypropylene[J]. J Appl Polym Sci,2010,108(5):3370-3379.
[16] LUO B,LI H,ZHOU C,etal. Mechanisticinsights into the shear-inducedβ-form crystal formation of i PP[J].Macromol Chem Phys,2016,217(12):1354-1360.
[17]CERMK R,OBADAL M,PONIL P,et al. Injectionmouldedα-andβ-polypropylenes:II. Tensile properties vs.processing parameters[J]. Eur Polym J,2006,42(9):2185-2191.
[18]罗宝晶.等规聚丙烯结晶机理研究[D].天津:天津大学,2017.
[19]李文东,杨桂生.分子量及其分布对聚丙烯力学性能和结晶行为的影响[J].高分子材料科学与工程,1996(1):41-46.
[20]雷华,徐涛,于杰.分子量及其分布对聚丙烯材料结晶形态的影响[J].高分子材料科学与工程,2004,20(5):166-168.
[21]张典.分子量和热处理对i PP挤出拉伸薄膜聚集态结构的影响[D].郑州:郑州大学,2014.
[22]李素云.分子量对制品微观结构的影响[J].合成树脂及塑料,1987(4):27-32.
[23]谢安准.高温熔融对PP/EPR/PE-UHMW分子链扩散作用以及流变和结晶性能的影响[J].中国塑料,2016,30(3):16-21.
[2]唐毓婧,门永锋.剪切速率对等规聚丙烯的结晶和形貌的影响[J].高等学校化学学报,2016,37(2):367-372.
[3] KITADE S,ASUKA K,AKIBA I,et al. Shear-induced pre-crystallization structures of long chain branched polypropylene under steady shear flow near the melting temperature[J]. Polymer,2013,54(1):246-257.
[4] CHEN Y H,FANG D F,LEI J,et al. Shear-induced precursor relaxation-dependent growth dynamics and lamellar orientation ofβ-crystals inβ-nucleated isotactic polypropylene[J]. J Phys Chem B,2015,119(17):5716-5727.
[5] LI Y,SHEN K. Theβ-andγ-form distributions of isotactic polypropylene injection molding controlled via melt vibration[J]. J Macromol Sci Part B,2008,47(5):1000-1007.
[6] VALDO MEILLE S,BRüCKNER S. Non-parallel chains in crystallineγ-isotactic polypropylene[J]. Nature,1989,340(6233):455-457.
[7] ANGELLOZ C,FULCHIRON R,DOUILLARD A,et al.Crystallization of isotactic polypropylene under high pressure(gamma phase)[J]. Macromolecules,2000,33(33):4138-4145.
[8] ADDINK MISS E J,BEINTEMA J. Polymorphism of crystalline polypropylene[J]. Polymer,1961(2):185-193.
[9]王艳,潘吉林,钟淦基,等.振动剪切诱导茂金属全同立构聚丙烯生长γ晶[J].高分子材料科学与工程,2010,26(6):111-113.
[10] MORROW D R,NEWMAN B A. Crystallization of low-molecular-weight polypropylene fractions[J]. J Appl Phys,1968,39(11):4944-4950.
[11] LOTZ B,GRAFF S,WITTMANN J C. Crystal morphology of theγ(triclinic)phase of isotactic polypropylene and its relation to theαphase[J]. J Polym Sci Part B Polym Phys,1986,24(9):2017-2032.
[12] MORROW D R. Polymorphism in isotactic polypropylene[J]. J MacromolSci,Part B,1969,3(1):53-65.
[13] ALAMO R G, KIM M H, GALANTE M J, et al.Structural and kinetic factors governing the formation of theγpolymorph of isotactic polypropylene[J]. Macromolecules,1999,32(12):4050-4064.
[14] VARGA J,KARGER-KOCSIS J. Rules of supermolecular structure formation in sheared isotactic polypropylene melts[J]. J Polym Sci Part B Polym Phys,2015,34(4):657-670.
[15] XIAO W,WU P,FENG J. Effect ofβ-nucleating agents on crystallization and melting behavior of isotactic polypropylene[J]. J Appl Polym Sci,2010,108(5):3370-3379.
[16] LUO B,LI H,ZHOU C,etal. Mechanisticinsights into the shear-inducedβ-form crystal formation of i PP[J].Macromol Chem Phys,2016,217(12):1354-1360.
[17]CERMK R,OBADAL M,PONIL P,et al. Injectionmouldedα-andβ-polypropylenes:II. Tensile properties vs.processing parameters[J]. Eur Polym J,2006,42(9):2185-2191.
[18]罗宝晶.等规聚丙烯结晶机理研究[D].天津:天津大学,2017.
[19]李文东,杨桂生.分子量及其分布对聚丙烯力学性能和结晶行为的影响[J].高分子材料科学与工程,1996(1):41-46.
[20]雷华,徐涛,于杰.分子量及其分布对聚丙烯材料结晶形态的影响[J].高分子材料科学与工程,2004,20(5):166-168.
[21]张典.分子量和热处理对i PP挤出拉伸薄膜聚集态结构的影响[D].郑州:郑州大学,2014.
[22]李素云.分子量对制品微观结构的影响[J].合成树脂及塑料,1987(4):27-32.
[23]谢安准.高温熔融对PP/EPR/PE-UHMW分子链扩散作用以及流变和结晶性能的影响[J].中国塑料,2016,30(3):16-21.