Lesson 9　Nitrile Rubber (NBR)

New Words

Notes

[1] These attributes arise from the highly polar character of acrylonitrile, the content of which determines the polymer’s particular balance of properties. 得益于丙烯腈结构的高极性，丁腈橡胶表现出的综合性能非常好。

[2] As acrylonitrile content increases, oil resistance, solvent resistance, tensile strength, hardness, abrasion resistance, heat resistance, and gas impermeability improve, but compression set resistance, resilience and low temperature flex deteriorate. 随着丙烯腈含量的提高，丁腈橡胶的耐油性、耐溶剂性、拉伸强度、硬度、耐磨性、耐热性和气密性会提高，但是抗压缩永久变形性、弹性和低温回弹性会降低。

[3] Nitrile elastomers do not crystallize when stretched and so require reinforcing fillers to develop optimum tensile strength, abrasion resistance, and tear resistance. 丙烯腈类的弹性体拉伸时不会发生结晶现象，没有自补强性，因此需要加入补强填充剂以获得理想的拉伸强度、耐磨性和抗撕裂性能。

[4] Although nitrile rubbers are broadly oil-resistant and solvent-resistant, they are susceptible to attack by certain strongly polar liquids, to which the nonpolar rubbers, such as SBR or natural rubber, are resistant. 尽管丁腈橡胶被广泛应用于制备耐油和耐溶剂制品，但是它不像天然橡胶和丁苯橡胶这样的非极性橡胶一样具有耐强极性溶剂的性能。

Exercises

1. Translate the first and second paragraphs of the text into Chinese.

2. Put the following words into English.

丁腈橡胶　　非极性橡胶　　　极性橡胶　　　三角V带　　　O形圈

丙烯腈　　　耐油性　　　　　耐溶剂性

Hydrogenated Nitrile Butadiene Rubber

Hydrogenated nitrile butadiene rubber (HNBR) is a relatively new elastomer, making its first appearance in 1984. The symbol for the generic material is HNBR, although HSN is sometimes used in literature, standing for highly saturated nitrile. It has all the attributes of NBR plus a very much higher heat resistance, dependent on the grade chosen. It also has very good weather and abrasion resistance, plus good mechanical strength. It is used in oilfields where it has resistance to amine corrosion inhibitors and better hydrogen sulfide resistance than NBR. It has established itself in automotive applications for timing belts, gaskets and O-rings, where higher temperature resistant elastomers are needed. Peroxide cured HNBR has heat aging resistance up to 150℃， based on around 1000 hours, while sulfur donor cured HNBR temperature resistance might drop to 135℃. Cost is somewhat less than conventional fluorocarbon rubber (FKM) on a weight basis, also since the density (using g/cm^3, which approximates to specific gravity) of HNBR is about half that of FKM, more products can be made for the same weight purchased.

Words and Expressions