Effect of Adhesion, Film Thickness, and Substrate Hardness on the Scratch Behavior of Poly(carbonate) Films

The effect of adhesion, film thickness, and substrate hardness on the scratch behavior of poly(carbonate) (PC) films was investigated. Films of various thickness were prepared by spin-coating solutions of PC in chloroform onto glass, ferroplate, Al 1100, Al 6022, and Al 6111 substrates. Adhesion between the films and the substrates was controlled by pretreatment of the substrates and the thickness of the films was controlled by the concentration of the PC solutions. Adhesion of the films to the glass substrates was measured by a blister test. Scratch tests were performed using a custom-built, progressive-load scratch tester with interchangeable diamond indenters; the resulting scratches were observed by optical microscopy, atomic force microscopy (AFM), and environmental scanning electron microscopy (ESEM). The critical normal load (i.e., the smallest applied normal load for which delamination of the film from the substrate was observed) was used as a criterion to determine the scratch resistance of the films. It was found that better film/substrate adhesion resulted in a higher critical load for delamination. As film thickness increased, the critical load and, thus, scratch resistance also increased. Substrate hardness had a strong influence on the scratch behavior of the PC films. For a low-hardness substrate (i.e., Al 1100), the work from scratching was mainly consumed by deforming the substrate. In the case of substrates with intermediate hardness (i.e., Al 6022, Al 6111, and ferroplate), the substrates were more resistant to the stresses that were generated in the films; hence, the deformation of the substrates was less severe. A high-hardness substrate (i.e., glass) resisted the applied load and resulted in higher stress concentrations in the films and at the interface. Consequently, a rougher surface inside the scratch track was observed.     

二异氰酸酯对聚碳酸亚丙酯熔体流变性能的影响

以4,4-二苯基甲烷二异氰酸酯（MDI）为扩链剂,在转矩流变仪上通过一步法对聚碳酸亚丙酯（PPC）进行了熔融扩链改性。结果表明,随着MDI用量的增加,扩链反应峰和平衡扭矩逐渐增大、平衡时间不断延长;红外光谱分析表明,扩链改性后的PPC在1600 、1535 cm-1处分别出现了苯环的骨架振动吸收峰和-NH的特征吸收峰;旋转流变分析表明,扩链改性后PPC的储能模量、损耗模量和复数黏度均随MDI用量的增加而增加;从Cole-Cole曲线可以看出,随着MDI用量的增加,扩链改性后PPC的相对分子质量逐渐增加,相对分子质量分布变宽,支化度提高;应力松弛测试结果表明,随着MDI用量的增加,松弛时间逐渐增加。     

Study on Thermal Properties and Crystallization Behavior of Blends of Poly(phenylene sulfide)/Poly(ether imide)

The thermal behavior of poly(phenylene sulfide) (PPS) blends with poly(ether imide) (PEI) was studied by differential scanning calorimeter (DSC). The crystallization temperature of PPS in blends shifted from 216.8°C to 226.4°C upon addition of 20–70% PEI contents. The heat of crystallization remained unchanged with less than 50% PEI in blends, whereas the heat of fusion decreased with increasing PEI content. The isothermal crystallization indicated that incorporating PEI would accelerate the crystallization rate of PPS. The activation energy of crystallization increased with addition of PEI. The equilibrium melting point of PPS/PEI blends was not changed with compositions.     

Controllable preparation of poly(alkylene carbonate)s and observation on their structure-related odd-even effect

The primary aim of this paper is to explore the influence of the number of CH₂ groups per -(CH₂)_nOCOO- repeat unit (Num_c) on the properties of poly(alkylene carbonate)s. A series of poly(alkylene carbonate)s with different Num_c, including PTMC (Num_c = 3), PTeMC (Num_c = 4), PPMC (Num_c = 5), PHMC (Num_c = 6) and PDMC (Num_c = 10) were investigated for that purpose by DSC and XRD techniques. The method of Sn(Oct)₂-catalyzed ring-opening polymerization was developed to prepare poly(pentamethylene carbonate)s (PPMC), which presented a controllable feature. Regarding crystallization rate and Tm of poly(alkylene carbonate)s, an interesting odd-even effect was first reported related to the Num_c. The order of crystallizing ability of poly(alkylene carbonate) was: PTMC (Num_c = 3) < PPMC(Num_c = 5) < PTeMC (Num_c = 4) < PHMC (Num_c = 6) < PDMC (Num_c = 10). Poly(alkylene carbonate)s characterized with even Num_c appeared to readily crystallize relative to that with odd Num_c.     

碳酸钙改性聚碳酸亚丙酯研究

利用双螺杆挤出机研究了分别填充不同表面改性的碳酸钙后对聚碳酸亚丙酯片材专用料(PPC101)性能的影响。结果表明:随着碳酸钙(CaCO3)用量的增加,试样的维卡软化温度皆呈上升趋势,未进行表面处理的碳酸钙填料对PPC101维卡软化温度的提高更明显;填料是否进行表面处理对PPC101材料的拉伸性能影响不大,随着填料用量的增加,未进行表面处理和硬脂酸处理的碳酸钙填充PPC101材料的拉伸强度均呈先上升后基本稳定的趋势,而使用铝酸酯的碳酸钙填充PPC101材料的拉伸强度几乎不变;随着填料用量的增加,无论填料是否进行表面改性,试样的冲击强度和熔体质量流动速率均呈下降趋势;而且密度均呈线性上升趋势。     

Poly(lactide-co-trimethylene carbonate) and Polylactide/Polytrimethylene Carbonate Blown Films

In this work, poly(lactide-co-trimethylene carbonate) and polylactide/polytrimethylene carbonate films are prepared using a film blowing method. The process parameters, including temperature and screw speed, are studied, and the structures and properties of the P(LA-TMC) and PLA/PTMC films are investigated. The scanning electron microscope (SEM) images show that upon improving the content of TMC and PTMC, the lamellar structures of the films are obviously changed. With increasing TMC monomer or PTMC contents, the elongation at the break is improved, and the maximum is up to 525%. The water vapor permeability (WVP) results demonstrate that the WVP of the PLA/PTMC film increased with the increase in the PTMC content, whereas the WVP of the P(LA-TMC) film decreased. Thermogravimetric (TG) measurements reveal that the decomposition temperatures of the P(LA-TMC) and PLA/PTMC films decrease with increases in the TMC and PTMC contents, respectively, but the processing temperature is significantly lower than the initial decomposition temperature. P(LA-TMC) or PLA/PTMC film can extend the shelf life of apples, for instance, like commercial LDPE film used in fruit packaging in supermarkets.     

Adhesion and Scratch Resistance of Polycarbonate Films on Ferroplate Substrates: Effect of γ-APS Primers

The influence of γ-aminopropyltriethoxysilane (γ-APS) primers on the adhesion and scratch resistance of polycarbonate (PC) films on ferroplate substrates was determined from the critical normal loads at which debonding of the films from the substrates occurred during scratch testing. The critical load was a strong function of the concentration of the aqueous solutions from which the γ-APS primers were adsorbed and of the thickness of the primer films. Thus, the critical normal load increased from 0.09 ± 0.02 N to 0.31 ± 0.07 N as the concentration of the γ-APS solutions increased from 0.05% to 0.2%, respectively. However, the critical load increased only slightly as the solution concentration increased beyond 0.2%. The increase in critical load as concentration of γ-APS solutions increased was related to the formation of an interphase involving chemical reaction and physical entanglement of PC and γ-APS molecules. The critical load for debonding of PC films from the substrates also depended strongly on the temperature at which the γ-APS films were dried before application of the PC films. Thus, the critical normal loads for debonding were 0.31 ± 0.07, 0.20 ± 0.02, and 0.05 ± 0.01 N for γ-APS films that were dried for 15 min at room temperature, 60°C, or 110°C, respectively. The decrease in critical load with increasing drying temperature was attributed to the greater cross-link density in γ-APS films that were dried at elevated temperatures, which limited interdiffusion and physical entanglement of PC and γ-APS molecules. High reaction temperature of γ-APS and PC induced a fragmentation of amine. However, it also increased the probability of amines to react with carbonate because of increasing mobility of PC chains. Optimization of these two factors was required to obtain the greatest adhesion and scratch resistance. Chemical reactions occurring between PC films and γ-APS primers were investigated by reflection-absorption infrared spectroscopy (RAIR) and X-ray photoelectron spectroscopy (XPS) using diphenyl carbonate (DPC) as a model compound. The carbonyl absorption band of neat DPC was observed at 1780 cm^-1. However, two carbonyl bands were observed at 1738 and 1652 cm^-1 in RAIR spectra of γ-APS films that were reacted with DPC and were assigned to urethane and urea groups, respectively. XPS results revealed that urethane was the main reaction product between DPC and γ-APS. It was concluded that urethane groups formed by the reaction of PC with γ-APS were responsible for adhesion and scratch resistance of PC to ferroplate substrates that were primed with γ-APS.     

聚对苯硫醚、聚间苯硫醚及其共聚物的合成与表征

用硫磺、对二氯苯和间二氯苯为原料,在极性有机溶剂六甲基磷酰三胺中合成了聚对苯硫醚(p-PPS)、聚间苯硫醚(m-PPS)及其共聚物.用裂解气相色谱、红外光谱、X-射线衍射及热分析对所得聚合物的结构和热性能进行了初步研究.结果表明:p—PPS和m—PPS都是结晶性聚合物,间位结构引入到p-PSS的结构中明显地破坏了p-PPS的高度结晶性,降低了耐热性,但最大失重速率处温度却无多大变化.这一共聚改性途径可望用于改进p—PPS的刚性,提高其韧性.     

Adhesion of Pure and CaCO3 Filled Latex Films on Poly(ethylene terephthalate)

Adhesion to poly(ethylene terephthalate) of carboxylated styrene-butadiene latex films, filled with calcium carbonate particles, was studied in this work. The acid content (2, 4 or 6 wt%) the degree of crosslinking (25, 50 or 75 wt% of insoluble polymer) of the latex particles, and the percentage of filler (0, 20, 40, 60, 80 or 90wt%) were varied. A peel test at 180° was used.

It was shown that, for the lowest filler percentages (up to 60 wt%), the films were non-porous and adhesion decreased when the peel rate, the percentage of filler, the degree of crosslinking and the acid content increased. Failure was always localized at the film-support interface (except at very low peel rate). At low peel rate, stick-slip was observed. The adhesion lowering can be explained by a decrease of the energy dissipation during peeling due to a reduced mobility of the polymeric chains. At high filler percentage (80 or 90 wt%), the films became porous and the level of adhesion very low. Failure occurred in the bulk of the latex film. The peel rate dependence was reversed; adhesion increased at higher speed. Owing to its marked importance in this system, the mechanism of the stick-slip phenomenon is especially discussed.     

Double propagation based on diepoxide, a facile route to high molecular weight poly(propylene carbonate)

Poly(propylene carbonate) (PPC) with number average molecular weight (M_n) higher than 200 kg/mol was prepared via the terpolymerization of carbon dioxide, propylene oxide and diepoxide using Y(CCl₃OO)₃-ZnEt₂-glycerine coordination catalyst. When equimolar ZnEt₂ and diepoxide were used, double propagation active species were generated in situ by nucleophilic attack of metal alkoxide on diepoxide, leading to PPC of doubled M_n value. The molecular weight of PPC has dramatic influence on its thermal and mechanical performances. PPC with M_n of 227 kg/mol showed modulus of 6900 MPa, while the modulus of PPC with M_n of 109 kg/mol was only 4300 MPa. Moreover, when M_n increased from 109 to 227 kg/mol, a 37 °C increase of the onset degradation temperature was observed.     

聚丙烯酸钠吸水性树脂的粘附性能测试及表征

为探讨聚丙烯酸钠吸水性树脂的粘附性能,设计了一种对其粘附性能的测定方法并进行了测试及表征,讨论了不同实验条件对树脂粘附性能的影响.结果表明,该吸水树脂的粘附性能随吸水量、初始压力和分离速率的增加具有一定的变化规律,并根据高分子结构理论、粘接的机械互锁理论和应力松弛等理论进行了解释.     

二(三氯甲基)碳酸酯的分析与检测

指出了建立适用于二(三氯甲基)碳酸酯(BTC)的简便、快速、准确的分析方法的重要性。讨论了BTC的定性分析、定量分析和检测方法。     

Effect of Inorganic Filler on the Crystallization,Mechanical Properties and Rheological Behavior of Poly(trimethylene terephthalate)

Poly(trimethylene terephthalate) filled with nano-CaCO₃ and ultra-fine talc was prepared by melt blending using a co-rotating twin screw extruder. The effect of these two inorganic filler on the crystallization and melting behavior, mechanical properties and rheological behavior of PTT were characterized. The DSC results indicated that both nano-CaCO₃ and ultra-fine talc exhibited heterogeneous nucleation effect on the crystallization of PTT, and more significant nucleation effect were observed in PTT/nano-CaCO₃ composite due to the smaller size and better dispersion of nano-CaCO₃ in PTT matrix. Mechanical properties study suggested that the incorporation of nano-CaCO₃ and ultra-fine talc greatly improved the tensile and flexural properties of PTT. Ultra-fine talc tends to lower the impact properties, while nano-CaCO₃ tend to increase the impact strength of the PTT/nano-CaCO₃ composite. When 2 wt.% of nano-CaCO₃ was added, the impact strength increased by one time. Rheological behavior study indicated nano-CaCO₃ exhibited plasticization effect on PTT melt and decreased the viscosity of PTT, while ultra-fine talc increased the viscosity of PTT due to the hindrance of the layer structure of talc.     

增塑剂对生物降解塑料聚乳酸结晶形态的影响

采用熔融共混方法制备了聚乙二醇(PEG)和聚乳(酸PLA)的共混物,并借助差示扫描量热仪和广角X射线衍射仪研究了在80~140℃等温结晶时PEG对PLA结晶形态和熔融行为的影响。结果表明:100℃以上时PLA的结晶度随结晶温度的升高逐渐增加;100℃以下时PLA的结晶度随PEG含量的增加逐渐增大。110℃以下时,晶面间距随结晶温度的升高和PEG含量的增加而逐渐减小;110℃以上时,晶面间距保持不变;当加入15%的PEG时PLA的晶面间距不受结晶温度的影响结,晶生成的是稳定的α晶。     

聚甲基乙撑碳酸酯/乙烯-乙烯醇共聚物/黏土复合材料的流变性能与阻透性能

采用熔融共混的方法制备了聚甲基乙撑碳酸酯(PPC)/黏土和PPC/乙烯-乙烯醇共聚物(EVOH)/黏土纳米复合材料,测试了复合材料的流变性能和阻氧性能,并对其微观形态进行了分析。结果表明,当基材PPC相对分子质量较高时,PPC/黏土复合材料的复数黏度、储能模量和耗能模量也较高;随着黏土和相容剂马来酸酐接枝聚乙烯（PE-g-MAH）的添加, PPC/EVOH复合材料的复数黏度和模量明显增加,PE-g-MAH的加入使PPC、EVOH和黏土之间的界面作用力增强,改善了PPC与EVOH的相容性,同时提高了PPC/EVOH复合材料的阻氧性能。     

Disparate polymerization facilitates the synthesis of versatile block copolymers from poly(trimethylene carbonate)

A disparate polymerization technique is utilized for preparing versatile block copolymers from poly(trimethylene carbonate) (poly(TMC)). In this study, 4-(chloromethyl)benzyl alcohol (CBA) is used for the disparate polymerization. The hydroxyl group of CBA is involved in ring-opening polymerization and the benzyl chloride group is involved in incorporating dithiocarbamate for pseudo-living radical polymerization. First, TMC is polymerized from the hydroxyl group of CBA by using an organocatalyst. The benzyl chloride group in CBA is modified using a dithiocarbamate, and then vinyl and methacrylate monomers are polymerized by photo-driven pseudo-living radical polymerization. The resulting block copolymers are versatile and the molecular weight distribution is reasonably narrow. In the present study, N-isopropylacrylamide, acrylamide glycolic acid, and 2-hydroxyethyl methacrylate are used for the disparate polymerization. The resulting block copolymers could be well dissolved in water by incorporation of hydrophilic segment into hydrophobic poly(TMC). The solution property is characterized in terms of hydrophobic domain formation and phase transition under ambient conditions. Moreover, enzymatic degradation is evaluated by using a copolymer-coated substrate. The block copolymer synthesis technique is considerably versatile, and the resulting polymer function can be freely designed. The disparate polymerization technique is a promising approach that provides universal materials for integrating biodegradable polyesters and functional polymers.     

Study on the Crystallization Kinetic and Characterization of Poly(lactic acid) and Poly(vinyl alcohol) Blends

In this study, poly(lactic acid) (PLA) and poly(vinyl alcohol) (PVA) blends, with PLA/PVA mass ratios of 100/0, 90/10, 80/20, 70/30, 60/40, 50/50, and 40/60, were prepared by means of the melt blending method. The result of torque measurements and thermal gravimtric analysis tests showed that the addition of PLA can decrease the melt viscosity of PVA and that the second degradation step of PVA nearly disappeared for the PLA₈₀/PVA₂₀ blend. The absorbance peaks of the carbonyl group and the hydroxyl group in the Fourier transform infrared spectra of PLA/PVA blends had significant shifts to lower wave numbers, indicating that there were interactions between these two groups. Combined with the result of the differential scanning calorimetry curves, this interaction would be favorable for improving miscibility. The X-ray diffraction patterns and the polarized light microscope (PLM) micrographs showed that PVA can serve as a nucleating agent to promote the crystallization of PLA in PLA/PVA blends. Moreover, the PLA₈₀/PVA₂₀ blend gave the highest growth rate of PLA spherulite.     

碳酸二（4-甲基苯）酯合成及工艺研究

研究了三光气（BTC）与对甲酚反应合成碳酸二（4-甲基苯）酯的新方法,并对温度、酚钠盐浓度、三光气用量等因素进行考察。得到合成碳酸二（4-甲基苯）酯的优化工艺条件为温度26℃,酚钠盐浓度为2．90mol／L,n（三光气）：n（对甲酚）=1：0．51,收率96．4％,含量达98％以上。     

聚乙基醚碳酸酯二醇增韧环氧树脂

八成以羟基封端的脂肪族聚碳酸酯－聚惭基醚碳酸酯二醇（ＰＥＥＣＤ）,并用于环氧（ＥＰ）树脂的增韧。探讨了ＰＥＥＣＤ的相对分子质量、加入量等因素对增韧效果的影响。通过红外光谱分析、扫描电镜、差示扫描最热分析以及力学性能测试等方法研究了增韧ＥＰ的结构与性能的关系。     

Viscoelastic Behavior and Deformation Mechanism of Soft Poly(vinyl chloride)

Effect of plasticizer, filler (CaCO₃, carbons), and nitrile-butadiene rubber on the elastic network structure of plasticized PVC was studied by step-cycle and stress relaxation measurements. It is proposed that the network of plasticized PVC comprise the main network (the true Gaussian network) formed by the entanglement of molecular chains and the secondary network formed by the interaction of chains (van der Waals force). The critical true strain at turning point on curves of recovery strain (?_c), residual strain (?_S), and viscous stress (Δσ) versus the true strain (?_H), respectively only depends on the entanglement density of main network. While, the recovery strain, the residual strain and the viscous stress relate to the secondary network. Plasticizer, CaCO₃, and carbons don't influence the main network structure, but can change the secondary network structure of PVC material. Nitrile-butadiene rubber, however, can change both the main and the secondary network structure of PVC material.