Rate-dependent large deformation behavior of PC/ABS

Rate-dependent large deformation behavior of the alloy of polycarbonate and acrylonitrile-butadiene-styrene (PC/ABS) is experimentally investigated over a crosshead speed range of 1-3000 mm/min. Three-dimensional non-contact digital image correlation (DIC) method is used to measure the large deformation of polymer specimens. Numerical simulation of geometry effect on the necking process of specimens is done for the specimen with two section sizes. It is found that the width contracts less than the thickness due to its larger size than the thickness for specimens with rectangular sections, and the relations between two lateral contraction ratios and engineering strains are geometry dependent, but independent of loading speeds. The influence of strain rates on local volume ratios of PC/ABS is also discussed. Based on the experimental results, a simple phenomenological constitutive model with six parameters is proposed for the glassy polymer, in which the effect of strain rate and its variation during constant crosshead speed loading tests is considered, and can be used in constant true strain rate or constant principal stretch rate loading condition.     

成分因素对PC/ABS合金暴露在烷基苯中力学性能的影响研究

通过万能拉伸试验机检测聚碳酸酯/丙烯腈?丁二烯?苯乙烯共聚物（PC/ABS）合金置于烷基苯后拉伸应变和拉伸强度的变化,研究了烷基苯对其力学性能的影响规律。结果表明,经过60 ℃烷基苯浸渍处理30 d后,分别添加了马来酸酐接枝低密度聚乙烯（PE?g?MAH）、马来酸酐接枝ABS（ABS?g?MAH）、甲基丙烯酸缩水甘油酯接枝乙烯?1?辛烯共聚物（POE?g?GMA）的PC/ABS的断裂拉伸应变变化率下降了58.8 %、25.4 %和41.3 %;相比于ABS,PC组分是导致断裂拉伸应变下降的一个关键因素;有效的相容剂能延长PC/ABS合金在类烷基苯溶剂中保持力学性能稳定性的时间;阻燃剂分散在PC/ABS体系中,在烷基苯渗透作用下更容易发生韧?脆行为转变。     

ABS树脂中胶含量对PC/ABS合金性能及微观结构的影响

采用胶含量(质量分数,下同)为60％的丙烯腈-丁二烯-苯乙烯接枝共聚物(ABS)接枝粉料与苯乙烯-丙烯腈共聚物(SAN)以不同比例进行共混,制备了胶含量范围为10％～55％的ABS树脂.将胶含量不同的ABS树脂与聚碳酸酯(PC)以30/70、50/50、70/30的质量比利用熔融共混技术,制备了组成不同的PC/ABS共混物,考察了ABS树脂胶含量对不同组成的PC/ABS合金性能的影响.研究结果表明:随着ABS树脂中胶含量的增加,ABS树脂的冲击强度不断提高,屈服强度、模量及熔体流动速率逐渐降低.随着PC/ABS合金中ABS胶含量的增加,合金的冲击强度显著提高,ABS树脂中胶含量大于30％以后,合金的冲击强度变化不大,且3种组成的PC/ABS合金的冲击强度相差不大.合金的屈服强度、模量及熔体流动速率却随着ABS中胶含量的增加不断降低,其中组成为30/70的PC/ABS合金最低.利用扫描电镜观察了PC/ABS组成为70/30合金的微观结构,研究表明,ABS树脂形成连续相,PC为分散相,随ABS树脂胶含量的增加,合金的相形态变得更精细.     

PC/ABS合金的力学性能研究

应用双螺杆挤出机，将聚碳酸酯(PC)分别与2种具有不同粘度的ABS(丙烯腈／丁二烯／苯乙烯共聚物)树脂(ABS 747和ABS 757)进行熔融共混，制备出二元合金体系。在室温下测量了2种合金的拉伸性能和Izod冲击性能。结果表明，2种合金的拉伸性能对PC含量的依赖性截然不同，而冲击性能则较为相似。在相同条件下，PC／ABS 757的拉伸性能和冲击性能均优于PC／ABS 747，且前者在拉伸性能方面显示出一定的协同效应。     

SAM树脂对PC/ABS合金的改性研究

采用苯乙烯-丙烯腈-马来酸酐三元共聚物(SAM树脂)代替PC/ABS合金中的部分SAN树脂,研究了SAM树脂在SAN树脂中的含量对不同胶含量的PC/ABS合金性能的影响。结果发现,用SAM树脂代替一部分SAN树脂后,PC/ABS合金的冲击强度和断裂伸长率随SAM树脂用量的增加略有增加,合金的拉伸屈服强度基本不变,熔体流动速率降低。SAM树脂引入后,PC/ABS合金的综合性能变化不大,共聚马来酸酐的引入并没有起到增容作用,部分性能的提高是由于SAM树脂与SAN树脂的分子特性不同引起的。     

Cavitational Strain Contribution to Tensile Creep in Vitreous Bonded Ceramics

Analysis of the role of cavitation during uniaxial creep deformation in vitreous bonded ceramics reveals that the cavity volume contributes only to the strain in the direction parallel to the tensile stress regardless of the shape and orientation of cavities. Creep asymmetry results from the fact that cavitation preferentially contributes to axial tensile strain while the strain observed under the same conditions in compression is produced only by volume-conserving mechanisms. The contribution of cavitational strain in the axial tensile strain is equal to the volume fraction of cavities and proportional to the difference between tensile and compressive strains in the axial direction. The density change method and a newly proposed method based on the difference in the axial strains were used for separating the cavitational from the true tensile strain in self-reinforced silicon nitride. Both methods consistently revealed more than 90% contribution of cavitation to the total tensile strain. Cavitation is concluded to be the dominant mechanism of tensile creep deformation in vitreous bonded ceramics because the reported volume fractions of cavities during their deformation are usually in the range of 70–90% of tensile strain.     

PC/ABS/聚硼硅氧烷阻燃合金的性能

采用X射线能谱分析(EDX)研究了PC/ABS/聚硼硅氧烷阻燃合金的燃烧行为,同时考察了阻燃PC/ABS合金的力学性能和加工性能。结果表明,聚硼硅氧烷(PB)中的Si元素会随着燃烧过程的进行逐渐在合金表面进行富集,形成富含Si的绝缘炭层覆盖在基体表面,阻止合金继续燃烧,从而有效提高了PC/ABS合金的阻燃性能。聚硼硅氧烷使PC/ABS合金体系的力学性能有所下降,但拉伸强度下降较少,PB对PC/ABS合金的冲击强度影响较大。在阻燃PC/ABS合金体系中加入相容剂马来酸酐接枝ABS,可使合金体系的力学性能得到明显提高。适量的PB可以改善PC/ABS合金的加工性能。     

硫酸钙晶须改性PC/ABS合金材料的性能研究

以硫酸钙晶须、硅烷偶联剂为改性剂,通过熔融挤出法制备了聚碳酸酯/丙烯腈-丁二烯-苯乙烯共聚物/硫酸钙晶须(PC/ABS/CSW)合金材料,研究了CSW和偶联剂用量对合金材料的力学性能、耐应力开裂性能及熔体流动性能的影响。结果表明:改性后的CSW在PC/ABS基体中分散均匀,PC/ABS基体的拉伸强度提高了17.3%,冲击强度提高了10.3%,同时,其耐应力开裂性能也有很大提高。     

Preparation and properties of PC/SAN alloy modified with styrene‐ethylene‐butylene‐styrene block copolymer

A polycarbonate (PC)/ poly (styrene‐co‐acrylonitrile) (SAN) alloy modified with styrene‐ethylene‐butylene‐styrene (SEBS) block copolymer was prepared and the influence of SEBS content, PC content, and types of modifier on Izod notched impact strength, tensile strength, flexural strength, and Vicat softening temperature was studied. The results showed that the addition of SEBS could obviously increase the Izod notched impact strength and the elongation at break and decrease the tensile and flexural strength and Vicat softening temperature. PC/SAN alloy modified with SEBS had better mechanical properties than the PC/SAN alloy modified with ABS. DSC analysis and SEM photographs revealed that the SEBS was not only distributed in the SAN phase but also distributed in PC phase in a PC/SAN/SEBS alloy while the ABS was mainly distributed in SAN phase in a PC/SAN/ABS alloy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

马来酸酐接枝ABS的增容改性研究

研究了增容剂马来酸酐接枝ABS对PC／ABS合金、PA6／ABS合金及ABS／GF复合材料力学性能的影响。结果表明，该增容剂的加入明显提高了PC／ABS合金的冲击强度和断裂伸长率，使PA6／ABS合金的各项力学性能均明显提高，使ABS／GF复合材料的拉伸强度和断裂伸长率也有较大提高。     

光盘回收PC改性ABS树脂研究

用光盘回收的聚碳酸酯（PC）树脂制备了丙烯腈-丁二烯-苯乙烯共聚物（ABS）/PC合金,探讨了回收PC含量、增容剂种类对合金力学性能的影响。结果表明,ABS/PC合金的拉伸强度随回收PC含量的增加而逐渐增大,冲击强度则呈先增长后下降的趋势,在回收PC含量为10 %（质量分数,下同）时达到最大值;增容剂甲基丙烯酸甲脂-丁二烯-苯乙烯共聚物（MBS）比甲基丙烯酸环氧丙酯接枝乙烯-辛烯共聚物（POE-g-GMA）更能改善ABS和PC的相容性,显著提高合金冲击强度,当回收PC含量为5 %时,用MBS增容的ABS/PC合金的冲击强度比纯ABS提高了42.8 %。     

Polycarbonate and co-continuous polycarbonate/ABS blends: influence of notch radius

The influence of notch tip radius in the range of 1-0.002 mm was studied on polycarbonate (PC) and co-continuous PC/acrylonitrile-butadiene-styrene (ABS). Co-continuous PC/ABS blend was obtained by mixing PC and ABS containing 15% polybutadiene (PB) in a twin screw extruder. PC and PC/ABS specimens were injection moulded into test bars. A notch was milled-in, with notch tip radius of 1, 0.5, 0.25 and 0.1 mm. Very sharp notches with a radius of 0.015-0.002 mm were obtained with an Excimer LAZER. The specimens were tested by single edge notch tensile tests at 1 m/s (apparent strain rate 28.5 s⁻¹) and at different temperatures (−60 to 130 °C). Initiation and propagation phases of the fracture process were monitored and the brittle-ductile transition temperature (T_bd) determined. It appeared that the amount of deformation in the initiation phase of fracture was extremely sensitive to notch tip radius. Temperature measurements of the deformation zone showed that the size of the deformation zone decreased with decreasing notch radius. The T_bd of PC increased rapidly with decreasing notch radius, until the glass transition temperature was approached. Remarkably, for PC the notch sensitivity was strongest around the standard notch tip radius of 0.25 mm. This means that a small deviation of this standard notch leads to large deviations in the results. The PC/ABS blend was much less sensitive to notch tip radius and the T_bd was almost constant. Thus the sensitivity of PC to sharp defects can be neutralised by adding ABS.     

相容剂及其在PC/ABS合金中的应用

采用水相悬浮聚合法合成了SAN-g-MAH、SAN-g-MMA、SAN-g-GMA3种相容剂,比较了3种相容剂对PC/ABS合金的增容效果,着重研究了工艺条件对接枝率的影响及相容剂用量对合金力学性能的影响。结果表明,相容剂的最大接枝率可达5.76%,添加相容剂后,PC/ABS合金的力学性能有明显提高,拉伸强度和缺口冲击强度分别可达61.91MPa和10.12kJ/m2。     

MBS改性PC/ABS合金的研究

研究了PC/ABS合金的相容性及适宜的合金比例,探讨了MBS对PC/ABS合金的增容和增韧作用,MBS对PC/ABS合金的力学性能和形态结构的影响。结果表明:在PC/ABS合金(70/30)体系中,加入6份MBS形成的复合材料与没有加入MBS相比,其相畴分布更加均一,冲击强度提高了40kJ/m2,拉伸强度、弯曲强度和热变形温度得到了较好的保持。     

无卤阻燃PC/ABS合金

通过阻燃性能、力学性能测试及场发射扫描电镜(FE-SEM)分析,研究相容剂、增韧剂、磷酸酯阻燃剂对PC/ABS合金阻燃及力学性能的影响,结果表明:相容剂A使ABS在PC中的颗粒尺寸减少,对PC/ABS体系相容性最好,但对合金的冲击性能提高有限.丙烯酸酯类增韧剂B的加入显著提高了PC/ABS合金的韧性.磷酸酯类阻燃剂虽然对PC/ABS合金具有很好的阻燃效果,但极大降低了合金的冲击性能,不同的加工工艺对合金的力学性能影响很大.     

Impact behavior and modeling of engineering polymers

Because of their many unique and desirable properties, engineering polymers have increasingly been applied in applications where impact behavior is of primary concern. In this paper, the impact behavior of a glassy polymer acrylonitrile‐butadiene‐styrene (ABS) and a semicrystalline polymer alloy of polycarbonate and polybutylene‐terephthalates (PBT) are obtained as a function of impact velocity and temperature from the standard ASTM D3763 multiaxial impact test. As computer simulation of destructive impact events requires two material models, a constitutive model and a failure model, uniaxial mechanical tests of the two polymers are carried out to obtain true stress vs, true strain curves at various temperatures and strain rates. The generalized DSGZ constitutive model, previously developed by the authors to uniformly describe the entire range of deformation behavior of glassy and semicrystalline polymers for any monotonic loading modes, is calibrated and applied. The thermomechanical coupling phenomenon of polymers during high strain rate plastic deformation is considered and modeled. A failure criterion based on maximum plastic strain is proposed. Finally, the generalized DSGZ model, the thermomechanical coupling model, and the failure criterion are integrated into the commercial finite element analysis package ABAQUS/Explicit through a user material subroutine to simulate the multiaxial impact behavior of the two polymers ABS and PBT. Impact load vs. striker displacement curves and impact energy vs. striker displacement curves from computer simulation are compared with multiaxial impact test data and were found to be in good agreement.     

反应型相容剂对PC/ABS合金改性研究

对MAH、相容剂C官能化聚合物的作用机理以及作为反应型相容剂,对PC/ABS合金的相容改性和拉伸冲击性能进行了研究。结果表明,实验中应用的相容剂马来酸酐接枝聚丙烯、马来酸酐接枝ABS和新型反应性相容剂均可以提高PC/ABS共混体系的相容性,但是马来酸酐接枝聚丙烯和马来酸酐接枝ABS的加入都不同程度地降低了合金的拉伸强度,而新型反应性相容剂不仅具有更好的增韧效果,同时还有增强作用。这种新型增容剂用量少,成本可以接受,为PC/ABS合金的性能提高提供一个较好的选择。     

Effects of ABS‐g‐MAH on mechanical properties and compatibility of ABS/PC alloy

The effects of a compatibilizer, namely, an acrylonitrile–butadiene–styrene copolymer (ABS) grafted with maleic anhydrade (MAH) (ABS‐g‐MAH), on the mechanical properties and morphology of an ABS/polycarbonate (PC) alloy were studied The results showed that a small quantity of ABS‐g‐MAH has a very good influence on the notched Izod impact strength of the ABS/PC alloy without compromising other properties such as the tensile strength, flexural strength, and Vicat softening temperature (VST). The impact strength of the ABS/PC alloy, to a great extent, depends on the loading of ABS‐g‐MAH and the degree of grafting (DG) of MAH in the ABS‐g‐MAH. DSC analysis and SEM observation confirmed that ABS‐g‐MAH could significantly improve the compatibility of the ABS/PC alloy. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 831–836, 2001     

Plastic deformation of low‐density polyethylene reinforced with biodegradable polylactide,Part 2: Creep characterization and modeling

The behavior of low‐density polyethylene (LDPE) and two blends prepared with polylactide (PLA) was determined by means of a novel video‐controlled testing method under stretching at constant true strain rate, under creep at constant true stress, and under creep at constant nominal stress. Most tests were performed at 23°C and 50°C. In this second part, the experimental data are modeled with the G'Sell‐Jonas phenomenological law expressing the axial true stress versus axial true strain and axial true strain rate. This model describes correctly the various deformation stages: (i) initial viscoelasticity, (ii) plastic yielding, and (iii) strain hardening up to rupture. It shows clearly the reinforcing effect of the PLA particles that increases the yield stress in stretching experiments and slows down the deformation kinetics under creep. It is shown how the local stress/strain behavior is related to the standard force/extension curves. Consequently, it is proposed that tensile tests at constant true strain rates should be systematically preferred to creep tests for the characterization of constitutive relations because they take much less time to be performed. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers.     

PC/ABS合金的力学性能的研究

利用双螺杆挤出机对PC／ABS进行共混,并探讨了PC的质量分数、三种相容剂以及阻燃剂对PC／ABS合金性能的影响。结果表明,拉伸强度随PC含量增加而升高,弯曲强度与弯曲模量则下降,冲击强度则呈现先降后升的趋势;不同相容剂的加入对PC／ABS合金的力学性能均有不同程度的提高;三种阻燃剂中氮磷复合阻燃合金的效果最好。