PE/PP混杂纤维应变硬化碱激发复合材料力学性能研究

应变硬化碱激发复合材料(SHAAC)兼具低碳环保和高韧性的优点,但高昂的成本限制了其工程应用。为降低成本,研究采用PP纤维替代PE纤维,开发了一种混杂PE/PP纤维SHAAC,并通过轴压与轴拉试验及成本分析,探讨了不同PP纤维替代率(0%、25%、50%、75%和100%,体积分数)对混杂PE/PP纤维SHAAC的轴压、轴拉性能和成本的影响。结果表明:采用PP纤维替代PE纤维时,SHAAC的轴压、轴拉强度及裂缝控制能力随着纤维替代率的增加而降低,但在PP纤维替代率低于75%时,SHAAC仍可呈现伪应变硬化和多缝开裂现象;当PP纤维替代率为50%时,SHAAC极限拉伸应变最高(8.40%),且能保持较高的轴压和轴拉性能,同时成本可降低29.00%,且综合性能与成本比值最高。

高温熔融ICP-AES测定PE、PP中的Si含量

依据标准T/CPCIF 0096-2021,采用高温熔融—电感耦合等离子体原子发射光谱法(ICP-AES)测定聚乙烯(PE)、聚丙烯(PP)中的硅(Si)含量。四硼酸锂(Li_(2)B_(4)O_(7))作熔融试剂,975℃对PE、PP灰化后样品进行高温熔融处理,酒石酸—盐酸(HCl)于低温下对熔融后的玻璃液进行溶解,获得待测溶液。选择261.611 nm为Si元素最佳分析谱线,利用基体匹配的方法制备Si标准溶液系列,曲线范围在1.00~10.00 mg/L,Si检出限为0.25 mg/kg。选取5个样品开展精密度试验,RSD结果均为1.0%~3.0%;采用熔融法处理,获得加标回收率在95%~105%之间,精密度好、准确度高。对比了高温熔融和微波消解法,此2种方法均能较好的将样品完全溶解,其中微波消解法过程存在少量SiF4挥发损失,因此Si元素的处理上使用高温熔融法更有优势。

POM/PP/PE高刚耐热复合材料的制备及性能研究

为获得高刚耐热聚乙烯基复合材料用于工程结构的改善和优化,本文制备了聚甲醛(POM)/聚丙烯(PP)/聚乙烯(PE)三元复合材料。采用PE-g-MAH作相容剂改善POM/PP/PE三元体系的相容性,研究PE-g-MAH对POM/PP/PE复合材料性能的影响。当PE-g-MAH添加量达到7.5份时,复合材料屈服强度达到最大值24.76MPa,提升了15.4%;冲击强度达到最大值25.78kJ·m^(-2),提升了50.7%;屈服伸长率达到最小值13.96%,降低了29.3%。结果表明,PE-g-MAH的加入提高了POM/PP/PE复合材料的综合力学性能,既改善了材料的相容性,同时也大幅提高了复合材料的储能模量,材料的刚性和耐热性能均得到了改善。

PP&PE杂化材料用水性抗静电涂料的研制

以自制烯烃改性磺酸盐型水性聚氨酯为主体树脂,引入高Tg值水性氯化聚丙烯树脂作为改性树脂,通过添加复合导电颜填料和单壁碳纳米管,制备了PP&PE杂化材料用功能型水性抗静电涂料。该产品以水分为散介质,施工工艺简单,常温即可固化,是节能环保型产品;固化后形成的涂层在PP&PE杂化材料上附着力突出,机械强度高,具有持久、稳定的低电阻(≤105Ω)特性,可有效增加基材表面硬度和抗划伤能力,增强其耐候性,能够及时有效地消除材料表面的静电积累,防止静电火灾和静电爆炸的发生,保障生产经营安全。

Barrier, Adsorptive, and Mechanical Properties of Containers Molded from PET/PP Blends for Use in Pharmaceutical Solutions

In this study, the adsorptive properties of L-menthol, moisture vapor transmission rate, and mechanical properties of poly (ethylene terephthalate) (PET), polypropylene (PP), and their blends were evaluated in containers fabricated by injection molding without a compatibilizing agent. These containers intended to hold pharmaceutical solutions containing lipophilic chemicals such as L-menthol. By the addition of a small amount of PP, the moisture barrier properties of PET were effectively improved, but its anti-adsorptive property was reduced. The strength of the PET/PP blends was reduced, but some PET/PP blends were still able to bear the experimental load required for application in eye-drop containers. PET/PP = 9/1 and PET/PP = 8/2 were found to be most applicable for using in the fabrication of containers for medicinal solutions.

Rheological and mechanical properties of wood fiber-PP/PE blend composites

For evaluation of the rheological and mechanical properties of highly filled wood plastic composites （WPCs）, polypropylene/polyethylene （PP/PE） blends were grafted with maleic anhydride （MAH） to enhance the interfacial adhesion between wood fiber and matrix. WPCs were prepared from wood fiber up to 60 wt.% and modified PP/PE was blended by extrusion. The rheological properties were studied by using dynamic measurement. According to the strain sweep test, the linear viscoelastic region of composites in the melt was determined. The result showed that the storage modulus was independent of the strain at low strain region （〈0.1%）. The frequency sweep resuits indicated that all composites exhibited shear thinning behavior, and both the storage modulus and complex viscosity of MAH modified composites were decreased comparing to those unmodified. Flexural properties and impact strength of the prepared WPCs were measured according to the relevant standard specifications. The flexural and impact strength of the manufactured composites significantly increased and reached a maximum when MAH dosage was 1.0 wt%, whereas the flexural modulus after an initial decreased, also increased with MAH dosage. The increase in mechanical properties indicated that the presence of anhydride groups enhanced the interracial adhesion between wood fiber and PP/PE blends.

IMPROVED PROPERTIES OF METALLOCENE-CATALYZED LINEAR LOW-DENSITY POLYETHYLENE/POLYPROPYLENE BLENDS DURING ULTRASONIC EXTRUSION

Metallocene-catalyzed linear low-density polyethylene/polypropylene （mLLDPE/PP） blends were prepared by ultrasonic extrusion in this work. Their extrusion processing behaviors were estimated by online measured data, such as the die pressure and flow rate. Crystallization and mechanical properties of the blends were also investigated. The results show that the addition of PP improves the processing behaviors of mLLDPE, but has little effect on its mechanical properties. On the other hand, the addition of mLLDPE improves the impact strength of PP, but has little effect on its processing behavior. The processing behaviors and mechanical properties of mLLDPE/PP blends get further improved due to the presence of ultrasonic oscillation during extrusion. Compared with PP-rich blends, the apparent viscosity drop of mLLDPE-rich blends is more sensitive to ultrasonic oscillation. The ultrasonic oscillation affects the crystal nucleation, while barely the other crystalline behaviors of the blends.

GRAFTING OF PEROXIDE-INITIATED MALEIC ANHYDRIDE ON SPHERICAL PE/PPIN-REACTOR BLEND GRANULES

Spherical polyethylene/polypropylene (PE/PP) in-reactor blend granules with various ethylene/propylene molar ratios and high porosity were synthesized using a high yield TiCVMgCl2 supported catalyst. A solution of benzoyl peroxide (BPO)/maleic anhydride (MAH)/xylene (interfacial reagent) or BPO/MAH/St (comonomer) was absorbed onto the PE/PP in- reactor blend granules, and solid phase graft polymerization of MAH on PE/PP was conducted. The amount of grafted MAH on PE/PP was measured through chemical titration. The results showed that solid phase graft polymerization of MAH in PE/PP in-reactor blend granules produced graft copolymer with high amount of grafted MAH, and the amount of grafted MAH was raised slightly when St was introduced as comonomer. The graft in-reactor blend was fractionated into five fractions through temperature-gradient extraction fractionation (TGEF), and the fractions were analyzed by FTIR. The results revealed that MAH is mainly grafted on the PE segments, whereas MAH was predominantly grafted on the PP segments when St was present in the graft polymerization system. In addition, the final product is still in the form of regular spherical granules, which is beneficial for industrial processing.

Dynamic Mechanical Behavior and Prediction for PP/POE Blends

Polypropylene（PP）/ethylene-octene copolymer（POE） blends were prepared with a twin-screw extruder.Their dynamic mechanical behavior were systematically investigated.The results show that PP/POE blends are heterogeneities with a partial compatible two-phase structure,the glass transition temperature of PP phases in the blends tends to shift towards high temperature with increasing the POE content,and the glass transition temperature of POE phases shifts towards the low temperature with increasing the PP content.The Kerner＇s dispersed phase model and co-continuous phase model can reasonably predict the visco-elasticity of PP/POE blends with different compositions.Additionally,the morphological structure of the blends can be estimated via comparing the predicted DMA behavior with the experimental data.

Alkaline Hydrolysis of PP/EHDPET Blend Fibers

Polypropylene superfine fibers or cell porous fibers were prepared from the bi-component blend fibers of polypropylene/easlly hydro-degraded polyester(PP/EHDPET)by alkaline hydrolysis process. EHDPET is a kind of copolyester that can be rapidly hydro-degraded in the hot alkaline solution. This paper discussed the kinetics of alkaline hydrolysis of EHDPET, and the effect of catalyst, bulk ratio and the content of polypropylene grafted maleic anhydride (PP-g-MAH) on the alkaline hydrolysis process. Meanwhile, the morphological change of the outer surface of blend fibers during this process was also investigated by the technology of scanning electron microscope (SEM).

SPHERULITIC STRUCTURE AND MORPHOLOGY OF POLY(ETHYLENE SUCCINATE)/POLY(ETHYLENE OXIDE) (PES/PEO) BLENDS WITH ONE-STEP CRYSTALLIZATION

The spherulitic structure and morphology development of poly(ethylene succinate)/poly(ethylene oxide) (PES/PEO) blends with one-step crystallization behavior were observed by means of polarizing optical microscope.It was found that the pure PES spherulite in which the adequate quantity of PEO melt existed in the interlamellar regions,and the blending spherulite formed by both PES and PEO lamellae could form simultaneously.When the two types of spherulites contacted with each other the front of the blending ...

Thermal, Mechanical and Rheological Properties of Low Density/Linear Low Density Polyethylene Blend for Packing Application

Packaging is the subject of considerable commercial development by a variety of organizations around the world. In this study the mechanical, thermal and rheological properties were investigated for different blend ratios of low density polyethylene (LDPE) and linear low density polyethylene (LLDPE). The weight percent of the LDPEs used in the blends were 50, 60, 70, 80 and 90. The polymer blends were prepared in a twin screw extruder to produce a thin sheet (1-mm thickness) similar to the packaging grade. Tensile results showed that the 50/50 composition exhibited the highest stress at break, where the differential scanning calorimetry results indicated a co-crystalline phase in some blends. The results produced by the rheometer revealed the LLDPE effect over the complex viscosity and consequently blend easy processing. The present study conclusively demonstrates that at low weight percent of linear low density polyethylene in the blend displays better properties for packaging application.

Effect of CaCO3 on the Mechanical Properties of Polyethylene Terephthalate/Polypropylene Blends

The aim of this work was to study the influence of CaCO3 in both tensile and flexural mechanical properties of a PET(polyethylene terephthalate)/PP(polypropylene).Four compositions of PET/PP/CaCO3 blend were prepared by injection molding with CaCO3 content of 0,2,4 and 6 wt%.The samples were cut according to the ASTM(American Society for Testing and Materials)standard and tested by using universal testing equipment.The results show that the mechanical properties of the PET/PP/CaCO3 composites with 2%and 4 wt%of CaCO3 composition were better than that of the PET/PP composites.While the content of CaCO3 is 6 wt%,the serious phase separation between PET and PP resulted in poor mechanical properties of the PET/PP/CaCO3 samples.This study shows that CaCO3 has played a role to improve the tensile and flexural properties of the mixing product if it is present only in a small amount.

PPS+PTFE混纺针刺滤袋在燃煤电厂的应用分析

针对某燃煤电厂使用聚苯硫醚(PPS)滤袋不足一年时间即发生大面积破损的问题,制备面层不同PPS和聚四氟乙烯(PTFE)纤维质量比的PPS+PTFE混纺针刺滤袋,对其进行挂袋试验,并从面密度、透气性、拉伸性能、粉尘渗透情况、材质变化及微观形貌等方面分析使用前后PPS+PTFE混纺针刺滤袋的性能。根据试验数据进行PPS+PTFE混纺针刺滤袋使用寿命的预估分析,推算其剩余使用寿命。研究结果显示,制备的PPS+PTFE混纺针刺滤袋满足粉尘排放质量浓度长期低于10 mg/m3的要求;面层PPS和PTFE纤维质量比为50∶50时,制备的PPS+PTFE混纺针刺滤袋的整体使用寿命可达74个月。研究为燃煤电厂滤袋除尘器的超低排放及滤袋选型提供参考。

马来酸酐接枝PP/PE共混物及其木塑复合材料

通过聚丙烯(PP)与聚乙烯(PE)机械混合来模拟废旧塑料混合物,利用马来酸酐(MAH)对PP/PE混合物进行接枝改性,然后以接枝共混物作为基体与木纤维复合制备木塑复合材料。通过对比接枝前后的红外光谱图,证明MAH已成功接枝在PP/PE共混物上。力学测试结果显示:基体经过接枝改性后,复合材料的弯曲强度和无缺口冲击强度均大幅度升高,当MAH用量为1%时,弯曲强度提高了50.4%,无缺口冲击强度提高了90.8%,而以废旧塑料为原料制备的复合材料的弯曲强度和无缺口冲击强度分别提高40.2%和53.4%。微观相形态分析表明:通过接枝改性不仅改善了PP/PE共混体系的相容性,同时也显著改善了木纤维与PP/PE共混物之间的界面结合状况,因而宏观上表现为力学性能提高。这表明,共混接枝改性方法可能是利用混合废旧塑料制备高性能木塑复合材料的一条可行途径。

利用红外光谱成像技术研究PP/PE共混物

利用红外光谱对不同比例条件下制备的PP PE共混物进行了研究 ,通过对PP ,PE的特征吸收峰的分析 ,发现聚丙烯 (PP)特征峰峰面积与聚乙烯 (PE)特征峰峰面积的比值与PP/PE共混物的质量比之间存在较好的对应关系。利用特征吸收峰面积之比 ,借助红外成像技术对PP纤维热压在PE薄膜上制备的样品的研究得到了复合共混物的分布信息 ,发现其成像结果与偏光显微镜的结果有很好的吻合。实验研究结果表明采用红外成像技术 ,利用特征吸收峰面积之比可以进行对聚合物共混物的分相行为的研究。

PP/LLDPE共混体系的相容性及结晶行为

运用差示扫描量热法(DSC)研究了聚丙烯(PP)/线性低密度聚乙烯(LLDPE)共混物的相容性和结晶行为。实验结果表明,PP/LLDPE共混物为典型的具有机械相容性的共混体系;PP/LLDPE共混体系中,PP相结晶度的变化与LLDPE相的结晶度的变化相比较小;不论PP还是LLDPE,均随另一组分含量的增加,熔化开始温度都显著推迟,而熔化结束温度几乎不变。

PE/PP共混物卷绕丝微观结构的研究

用透射和扫描电子显微镜研究PP/PE共混物在熔融纺丝时 ,PE掺入对PP结构的影响。研究结果表明 :PE与PP存在一定程度的相互作用 ,PP中加入PE能改变卷绕丝中PP结晶结构 ;PP中加入质量分数低于 10 %的PE时可以顺利纺丝 ,所得的卷绕丝断裂伸长率较大 。

PP/PE熔体流动速率比与共混体系力学性能的关系

选择不同熔体流动速率(MFR)的乙-丙共聚型聚丙烯(PP)和聚乙烯(PE),分别配混出一系列不同熔体流动速率比(R_M=MFR_(PP)/MFR_(PE))的共混体系。深入探讨了共聚PP/PE共混体系的力学性能与PP和PE间R_M的关系。结果表明,在适宜的R_M范围內,PE能对乙-丙共聚型PP具有良好增韧增强效果。在0<R_M<25范围内,共混体系表现出脆-韧转变特征。大多数共混体系在5.0<R_M<15范围內的拉伸屈服强度、冲击强度、断裂伸长率和弯曲强度均有明显提高,体系综合力学性能最优。R_M>25后,体系性能劣化。

PPS/PES共混物及其碳纤维复合材料内耗行为的研究

本工作利用内耗测量方法研究了PPS/PES共混物及其碳纤维复合材料的相容性以及多重转变和松弛行为,结果表明:(1)PPS与PES存在分子运动水平上的相互作用,共混组份比是决定其相互作用程度的重要因素;(2)PPS/PES共混物及其碳纤维复合材料中的PES相的β转变与松弛的时间存在较宽的连续分布,其分布宽度随共混组份比变化而变化,当PES相对含量为80％时,松弛时间分布宽度出现最大值;(3)PPS/PES共混物及其碳纤维复合材料处于热力学亚稳态,热处理增大了PPS与PES的相分离程度,减弱了它们之间的相互作用;(4)低温区热历史对PPS玻璃化转变有较大影响,内耗峰高及峰温随起始测量温度的升高而下降。